US20100126212A1

US20100126212A1 - Binary fluid ejector and method of use

Info

Publication number: US20100126212A1
Application number: US12/541,821
Authority: US
Inventors: Wayne A. May
Original assignee: MAY-RUBEN TECHNOLOGIES Inc
Current assignee: MAY-RUBEN TECHNOLOGIES Inc
Priority date: 2008-08-14
Filing date: 2009-08-14
Publication date: 2010-05-27
Also published as: EP2324304A2; CN102187164B; WO2010019913A2; CA2691294A1; WO2010019913A3; CA2691294C; CN102187164A; EP2324304A4

Abstract

A binary-fluid oscillating-jet pressure exchange ejector and binary-fluid ejector refrigeration cycle as a method of use are disclosed. The ejector includes a high aspect ratio jet nozzle geometry, spatial domain jet modulation, serpentine jet stream morphology and distinct fluid pathway geometry capable of equilibrating or otherwise processing dissimilar fluids. As a method of use, the binary fluid ejector provides a means to substantially optimize the binary fluid set selected or otherwise formulated for employment in a binary-fluid ejector refrigeration cycle exclusively to favor refrigeration thermal performance (COP), without compromising the performance of the ejector itself.

Description

CROSS-REFERENCE

This application claims the benefit of U.S. Provisional Patent Application No. 61/088,957 filed on Aug. 14, 2008.

FIELD OF THE INVENTION

The embodiments of the present invention relate to two dissimilar operating fluids brought into contact via an exchange ejector and method of using the same.

BACKGROUND

Conventional ejector or jet type pumps may be characterized as direct energy transfer devices referring to the function where energy is transferred from a primary fluid to a secondary fluid by means of direct (intimate) contact between the two fluids. Another operating principle common to all gas-phase jet pumps is that high velocity, low static pressure, kinetic energy is used to entrain a secondary fluid, then the mixture is decelerated to a low velocity flow at higher static pressure, thus converting so called velocity head into pressure head, i.e. kinetic energy is converted into potential energy. This is the primary means for secondary fluid compression. A distinctive characterization of conventional ejector or jet pumps is that secondary fluid entrainment occurs by means of either 1) shear turbulence interaction at the interface between the primary and secondary fluids, referred to in research literature and patents as momentum exchange, turbulent shear, turbulent mixing entrainment, or 2) dynamic pressure force interaction at the interface between the primary and secondary fluids, often referred to in research literature and patents as pressure exchange.
There is a need for an ejector and method of use that handles two dissimilar fluids and includes at least one or more of the following: unique jet nozzle geometry, primary fluid jet morphology, jet modulation and ejector body geometry.

SUMMARY

The embodiments of the present invention relate to direct energy transfer between two dissimilar operating fluids brought into intimate contact by means of an unsteady-state oscillating-jet pressure exchange ejector and method of using the same. Further, the embodiments relate to the entrainment, transport and compression of a low energy working fluid by means of direct energy transfer from a higher energy motive fluid. The embodiments of the present invention also concern a new class of ejector purposefully dedicated to dissimilar fluid operation, thus the moniker binary-fluid ejector. An important distinction in this regard is that the operating fluids are not selected, formulated or otherwise optimized as a means to improve the performance of the ejector, but conversely, the ejector itself is purposefully dedicated to binary-fluid operation as a self-consistent functionality which results improved performance and efficiency. Conventional systems on the other hand teach that certain fluids and/or certain material properties of fluids can be selected or otherwise formulated as a means to improve the performance or efficiency of a jet ejector. The embodiments of the present invention teach a unique ejector tailored to the fluids, specifically dissimilar fluids, for the self-consistent purpose of creating a binary-fluid device. The embodiments of the present invention also relate to a binary-fluid ejector refrigeration cycle disclosed herein as one method of use.
In the context of this disclosure, binary fluid means a set of any two fluids that are dissimilar in chemical composition or material property except phase or state. Examples of such physical properties may include but are not limited to chemical composition, ratios of specific heat k (k=C_p/C_v, where C_pand C_vare specific heat at constant pressure and constant volume respectively), phase change enthalpy Δh_v(latent heat of vaporization), molecular mass and others. This definition specifically excludes conditions of state, such as pressure, temperature, velocity and phase (gas versus saturated vapor for example). This definition includes either or both fluids in the binary set whether they are self-consistent and homogeneous, that is, consisting of a single chemical compound or entity; inconsonant and heterogeneous, that is, consisting of a combination of two or more chemical compounds or fluid entities whether miscible or not; or hybrid and composite, that is, consisting of some carrier fluid that contains another fluid suspended as fluid particles necessarily immiscible (such as a mist or a two-liquid saturated vapor) or solid particles suspended and dispersed as colloids therein (airborne dust for example).
The term doublet fluid means a set of any two fluids differentiated by source, location or state. Examples of such differences may include but are not limited what system element a fluid is flowing from as a source, what system element a fluid is flowing towards as a supply, the location of the fluid in the system or device, or its state, such as pressure, temperature, velocity, specific volume (density), or phase, i.e. gas or vapor. The definition of doublet specifically excludes fluids that are differentiated by chemical composition or material property.
The term primary fluid shall mean the motive high-pressure supply fluid driving the ejector. The primary fluid is presented to and in communication with the jet nozzle, providing the source of fluidic energy for transfer to a secondary fluid. The term secondary fluid shall mean the reactive low-pressure working fluid entrained, compressed or otherwise pumped by jet action. The secondary fluid is presented to and in communication with the high-velocity primary fluid jet for the purpose of entrainment, motivation, transport and compression therewith, thus receiving fluidic energy from the primary fluid. The following are some examples of binary and doublet fluids. The list also demonstrates a convention used in this disclosure to indicate primary versus secondary fluids: water/pentane: a binary fluid where water is the primary fluid and pentane is the secondary fluid; pentane/water: a binary fluid where pentane is the primary fluid and water is the secondary fluid; water/water: a doublet fluid where water is the primary fluid and water is the secondary fluid; and pentane/pentane: a doublet fluid where pentane is the primary fluid and pentane is the secondary fluid.
Throughout the body of this disclosure, the term fluid shall be used and meant to include a fluid that exists in a gas or saturated vapor phase as it operates within or traverses through a binary fluid ejector; liquid phase is specifically excluded, the distinction being compressible versus incompressible. The primary and secondary fluids may exist in any of these two phases independent of each other. For example, the primary fluid may be in a gas phase, where the secondary fluid may exist in a vapor phase, or vice versa, or the primary and secondary fluids may exist in the same phase, gas or saturated vapor.
In this disclosure, the two types are differentiated by the operating principle responsible for secondary fluid entrainment, namely shear turbulence entrainment versus dynamic pressure entrainment. A second distinctive characterization applicable to gas-phase jet pumps is constant area mixing versus constant pressure mixing. Constant area mixing denotes a particular design where the ejector's mixing section downstream of the primary jet and entrainment area has a constant cross-sectional area relative to its length, thus providing a constant volume for mixing the two fluids as they progress towards the outlet end of the device. In this design, fluid volume is held constant while fluid pressure varies during the period of mixing. Conversely, constant pressure mixing denotes a mixing section within the ejector having a decreasing cross-sectional area with respect to its length, thus providing a constant pressure area in which the two fluids mix. In this design, fluid pressure is held constant while fluid volume varies during the period of mixing. A final distinctive operating principle is steady state versus unsteady state jet operation. Shear turbulence entrainment type ejectors are driven by a constant steady-state primary fluid jet, operating with an orientation and differential pressure that are fixed in space and time. Dynamic pressure entrainment type ejectors employ an unsteady-state primary jet that is pulsed in the time domain or otherwise moved, or oscillated in the spatial domain, or both. These operating principles are depicted in the form of a simple category diagram shown in FIG. 1.
As indicated in FIG. 1, by definition all jet pumps and ejectors involve intimate contact between the primary motive and secondary working fluids, hence the common category. Likewise, all jet pumps and ejectors exploit the fluid dynamic energy transform between velocity head and pressure head as a means to pump or otherwise compress one fluid with another. Foundational physics allows a high energy primary fluid jet to generate a low pressure area at high velocity, followed by a higher pressure area at some lower velocity, thereby using the energy transform and mass flow to collect, entrain, transport and compress a secondary lower energy working fluid. Persons skilled in the relevant art will understand and appreciate that notwithstanding the numerous and diverse ejector jet pump designs, geometries, and configurations, the physics of the fluid and thermal dynamics involved are the same. Hence, any conventional jet pump or ejector may be categorized by the foundational maxims depicted in FIG. 1 as operating principles thereof. The chart is pertinent to the art taught by this disclosure as will be explained below.
Since all ejectors involve the conduction of fluids at various pressures, temperatures and velocities, their design necessarily entails the geometry, sizes, cross-sectional areas, lengths and relative ratios between all parts and areas throughout the ejector's various fluid pathways. For example, it is widely known and understood by persons skilled in the art of gas-phase jet ejector design that ejector performance is related to certain non-dimensional ratios such as by example compression ratio γ (nomenclature below), expansion ratio χ, jet-nozzle to mixing throat area ratio φ, and a number of others. Ejector entrainment ratio ω=m_s/m_p, an important measure of ejector performance, increases as the area ratio φ and expansion ratio χ increase, and as the compression ratio γ decreases. Regardless of how modeled, the formulary and equations of state describing traditional ejectors contain fluid property terms for a single operating fluid as a doublet, even when the model differentiates the primary and secondary fluids by source, phase, or state (such as enthalpy, temperature, pressure, velocity, etc.). For example, consider equations (1, 2, & 3) that describe a typical ejector:
$\begin{matrix} M_{2}^{2} [1 + (1 - n_{d}) \frac{T_{2}}{T_{3}} ((\frac{\partial [\ln (\frac{T_{2}}{v_{2}})]}{\partial (\ln v_{2})}) + \frac{k}{1 - \frac{P_{4}}{P_{2}}})] = 1, & (1) \\ {(\frac{P_{3}}{P_{2}})}^{\frac{k - 1}{k}} - n_{d} M_{2}^{2} (k - 1) / 2 = 1, & (2) \\ A_{2} = \frac{m_{1} V_{1}}{(P_{2} k M_{2}^{2} + P_{2}) - P_{4}}, & (3) \end{matrix}$
where:

- M₂fluid velocity at position/state 2 in units of Mach number
- n_ddiffuser efficiency
- T_nfluid temperature at position/states 0 through 4 as indicated in FIG. 2
- v₂fluid specific volume at position/state 2 in FIG. 2
- k ratio of specific heat; k=C_p/C_v
- P_nfluid pressure, subscript n replacing position/states 0 through 4 where indicated in FIG. 2
- A₂cross sectional area at position 2 in FIG. 2
- m_nfluid mass flow rate at position/states 0 through 4 as indicated in FIG. 2
- V₁fluid velocity at position/state 1 in units of meters/second
- γ compression ratio; γ=P₃/P₄
- χ expansion ratio; χ=P₀/P₃
- φ jet-nozzle area to mixing throat area ratio; φ=A_m/A_t
- ω ejector entrainment ratio; ω=m_s/m_p
- s subscript s denoting the Secondary fluid
- p subscript p denoting the Primary fluid.

Referring to FIG. 2 for equations (1, 2, & 3) and the nomenclature above, the numerals 0 through 4 denote a position and/or a fluid state at that position (phase, pressure, temperature, velocity, etc.). The primary fluid flow, secondary fluid flow, jet nozzle, entrainment section E, mixing section M, and defusing section D are as shown. Equations (1) and (2) will yield solutions for M₂and P₂with measured or known values of n_d, k, P₀, P₃, and P₄. The optimum mixing area ratio φ, an important ejector design criteria, can then be extracted by substituting the calculated values of M₂and P₂in equation (3). Note that in all three equations above, the ratio of specific heat k and specific volume v denote a single value respectively for a single fluid, even though the fluid at that point in the ejector may be a mixture of the primary and secondary fluids. These and other equations that model the design and performance of gas-phase jet ejectors are only valid in the case where the primary and secondary flows are doublets of the same fluid. The salient distinction pertinent to this teaching is that these and other equations describing the design, geometry and performance of traditional ejectors fails to model the embodiments of the present invention unless the material property terms therein were expanded or otherwise modified to include two dissimilar fluids, instead of one fluid differentiated only by phase and/or state. Accordingly, a new class of gas-phase ejector called the binary-fluid ejector is disclosed wherein the binary-fluid ejector is differentiated by this critical principle of operation. FIG. 3 categorizes the prior art and the embodiments of the present invention by principles of operation. Note that some principles of operation are common to more than one type of ejector.
An important distinction exists between conventional ejectors that may be simply presented with dissimilar fluids and called upon to operate, and the embodiments of the present invention which are intentionally dedicated to function with dissimilar fluids. As an example, for any given mass flow rate m_s, m_p, entrainment ratio ω, and compression ratio γ, the dimensional values for E, M, D, d_t, d_n, d_m, and d_dwill be separate and distinct for a binary-fluid ejector dedicated to pentane/water versus a traditional ejector designed for water/water. The embodiments of the present invention cannot be modeled using conventional design equations or methodologies consistent with conventional systems. Further, for any given values of m_s, m_p, ω, and γ, the dimensional values for E, M, D, d_t, d_n, d_m, and d_dwould be separate and distinct for a binary-fluid ejector dedicated to water/pentane versus one dedicated to pentane/water, neither of which can be modeled using conventional equations or methodologies consistent with conventional systems.
In addition to this significant differentiation based on principle of operation, the embodiments of the present invention are unique with regard to jet nozzle geometry, primary fluid jet morphology, jet modulation technique and ejector body geometry. These and other novel design features are taught herein.
As it relates to one method of use, the embodiments of the present invention may offer certain advantages over traditional ejector refrigeration cycles. In particular, the embodiments of the present invention can be made integral with a binary-fluid ejector refrigeration cycle as one method of use, resulting in a significant improvement in performance over archetypal binary-fluid ejector refrigeration systems.
Despite over a century of research and development, modern ejector refrigeration systems are commercially viable in a limited number of special applications. Even in these extraordinary cases, traditional ejector refrigeration systems using conventional technology are energy inefficient, and thus, are only employed where extreme environmental conditions or operating circumstances outweigh their dismal coefficient of performance. This is true because shear turbulence entrainment ejectors suffer from a high level of irreversible energy loss associated with viscous turbulence at the interfacial boundary of the two fluids. While pressure exchange ejectors offer an incremental improvement in energy efficiency, they are still doublet-fluid devices, i.e. the primary and secondary fluids are differentiated by phase and/or state, and as such, operate at marginal performance if applied to a binary-fluid refrigeration cycle. This is an arresting observation in the context of the embodiments of the present invention and the method of use disclosed herein.
Ejector refrigeration cycles are necessarily thermally driven systems. This is the case because using a mechanical pump or compressor to pressurize the primary fluid used for the jet would counter the reason for using an ejector in place of the motor driven compressor a priori. Notwithstanding the poor energy efficiency of traditional ejectors, there is another equally significant reason for the meager coefficient of performance suffered by traditional doublet-fluid and binary-fluid ejection refrigeration systems: optimizing the working fluids to favor refrigeration performance versus ejector performance is counter-indicated. The converse is also true: optimizing the working fluids to favor ejector performance over refrigeration performance is counter-indicated. This conflict is subtle on its face, but significant with regard to the deleterious effect on performance and efficiency.
For example, in the case of a doublet-fluid ejector refrigeration system, namely one that employs a single working fluid, the design imperative for refrigerant selection is high phase change enthalpy Δh_v(large latent heat of vaporization). This is so because a fluid with a high value of Δh_vtransports a large quantity of heat per unit mass of fluid evaporated. This is a benefit because it limits the size of the evaporator, the size of the ejector and the mass entrainment ratio required of the ejector. However, counter to these benefits, a fluid with a high Δh_vvalue requires a large boiler as well as a large condenser (see FIG. 4). (The condenser must reject heat from both the primary and secondary fluids because the ejector mixes them.) The result is an offset of benefits that limits the system's thermal performance and efficiency; hence system coefficient of performance is held low. This counter indicating design conflict also increases system complexity and manufacturing cost.
In the case of binary-fluid ejector refrigeration systems taught by the prior art, videlicet one that employs two dissimilar fluids, an analogous conflict is present, but for a different reason. Should the primary fluid be selected or otherwise formulated to favor ejector performance, and the secondary fluid selected or otherwise formulated to favor refrigeration cycle performance, the two fluids must equilibrate through a single ejector, which is unable to function efficiently because it is designed to operate with single fluid doublets. Conversely, if the binary fluid set is selected or otherwise formulated to favor refrigeration performance solely, or, if the binary fluid set is selected or otherwise formulated to favor ejector performance solely, one or the other suffers with low operational efficiency, and the overall coefficient of performance is once again held low.
By contrast, the embodiments of the present invention are capable of performing efficiently with dissimilar fluids at higher entrainment and compression ratios due to its unique geometry, primary jet morphology and design philosophy. This design represents a foundational and significant performance distinction over that of conventional systems, allowing the fluids selected or otherwise formulated for employment in a binary-fluid jet ejection refrigeration system to be optimized to favor refrigeration performance, with no deleterious effect on ejector performance or efficiency.
The novel art of the embodiments of the present invention represents a new class of gas-phase jet ejector, a binary-fluid oscillating-jet pressure exchange device, comprised of unique rectangular body geometry, a high aspect ratio primary jet oscillating in the spatial domain, novel primary jet fluid morphology and distinct area ratios capable of equilibrating or otherwise processing dissimilar fluids. The design improves ejector performance or efficiency consistent as to function with dissimilar fluids for the dedicated purpose of functioning with dissimilar fluids. Further, the embodiments of the present invention provide a means to optimize the binary fluid set selected or otherwise formulated for employment in a binary-fluid ejector refrigeration cycle exclusively to favor refrigeration thermal performance (coefficient of performance (COP)), without compromising the performance or efficiency of the ejector itself.
Accordingly, one embodiment of the present invention is a binary-fluid gas-phase ejector for the purpose of self-consistent functionality, designed to equilibrate or otherwise process dissimilar fluids for the dedicated purpose of transferring fluidic energy between dissimilar fluids by means of direct fluid contact between the two. This is accomplished by designing ejector body shape, jet nozzle geometry, entrainment, mixing, and diffusion section lengths and areas, and the area ratios thereof to account for both sets of material properties associated with the two dissimilar fluids in the binary-fluid set.
An ancillary result of the binary-fluid design/dedication philosophy is higher mass entrainment ratios, greater compression ratios, and more efficient energy transfer at lower increases in entropy than conventional ejectors.
The embodiments of the present invention also improve the energy transfer efficiency, mass entrainment ratio, and compression ratio of pressure exchange type ejectors by means of a novel high aspect ratio primary jet nozzle having rectangular cross-sectional throat geometry.
The embodiments of the present invention also improve the energy transfer efficiency, mass entrainment ratio, and compression ratio of a pressure exchange type ejector by means of modulating the primary jet in the spatial domain, thereby periodically transecting the entrainment section thus producing an isochronal serpentine geometry in the fluid jet.
Further, the embodiments of the present invention also improve the performance of a pressure exchange type ejector by means of a novel fluid pathway cross sectional geometry that is more rectangular than round. This unique ejector body geometry improves mass entrainment of the secondary fluid at a lower increase in entropy by matching the cross sectional shape of the primary jet, which is largely rectangular. The mixing and diffusion sections of the ejector may also have this cross sectional shape, or tend towards this shape.
Additionally, the embodiments of the present invention is to improve the overall coefficient of thermal performance (COP) of a binary-fluid ejector refrigeration cycle by means of the embodiments of the present invention integral with the cycle as a method of use.
Pressure exchange type ejectors rely on a high velocity gas wave front supplied by an unsteady state primary fluid jet to transfer energy to a secondary fluid for the purpose of pumping and compressing the fluid. Motivation and entrainment occur at the interfacial boundary between this wave front and the secondary fluid. The vector component of the dynamic pressure that is parallel with the direction of flow at the wave front is the operative agent for energy transfer. Any volume of compressed gas behind this wave front not in direct contact with the secondary fluid cannot participate in the energy transfer, and as such, represents primary fluid simply ingested by the ejector, i.e. waste energy. Consequently, the surface to volume ratio of the primary fluid jet itself plays an important role in ejector performance.
Circular cross-sectional geometry of jet nozzle throats and ejector bodies are ubiquitous. By contrast, the embodiments of the present invention comprise a rectangular shaped jet nozzle presenting a high aspect ratio. For the purpose of this disclosure, the term “high aspect ratio,” as applied to the nozzle or the fluid jet itself, means that the ratio h/w is greater than one (1), h/w>1, where h is the height of the nozzle throat or fluid jet itself, and w is their width (see FIGS. 6 and 7 a, 7 b). The rectangular nozzle geometry of the embodiments of the present invention is superior to traditional circular nozzle geometry, even for modest aspect ratios. The greater surface to volume ratio of a rectangular primary fluid jet translates directly to significant improvement in mass entrainment ratio, compression ratio, and energy transfer between the primary and secondary fluids. This is true because for a pressure exchange type ejector, energy is transferred from the primary to secondary fluid at the interfacial boundary separating the two fluids. Consequently, for a given mass flow rate, a greater interfacial surface area results in a higher energy transfer rate. Accordingly, energy efficiency and pumping performance are greatly increased over conventional ejector designs.
This disclosure continues by teaching a novel primary jet modulation called bilateral reciprocation. Bilateral reciprocation is a type of jet modulation producing oscillatory fluid jet geometry in the shape of a regular serpentine (see FIGS. 7 a, 7 b). Note that FIG. 7 a is a top view of the fluid jet, FIG. 7 b is a side view, and that dimensions w and h correspond to the width (w) and height (h) of the nozzle throat shown in FIG. 6. Although the serpentine aspect of the jet stream's geometry may be archetype for some fluidic oscillators and amplifiers, the high aspect ratio of its geometry is unique, and its application to ejector design is novel. The oscillating motion may be generated via mechanical means that require moving parts, or fluidic means that require no moving parts.
The modulated fluid jet progresses through the ejector at a quasi-constant frequency, diminishing wavelength, decreasing velocity, and increasing pressure amplitude (see FIG. 8). Note that in this exemplar embodiment, a mechanical nozzle is shown reciprocating from side to side, thus alternately directing the fluid jet stream towards the contact points L and R indicated at 136. Secondary fluid is captured between the walls of the ejector and successive waves of the jet stream, thereby entrained as they supervene. Within the entrainment section of the ejector, the serpentine geometry of the fluid jet presents a dynamic pressure force to the secondary fluid at the interfacial boundary thereof, resulting in transfer of energy between the two fluids. The magnitude of this force vector is a function of the differential dynamic pressure between the primary and secondary fluids at the interfacial boundary, the primary fluid velocity in the area considered, and the frequency of jet modulation. Jet modulation or oscillation frequency is antecedent because it determines the magnitude of the longitudinal pressure vector which is a vector component of the total dynamic pressure available. Differential dynamic pressure at the interfacial boundary between the two fluids is responsible for secondary fluid energy exchange, not static pressure differential. As the jet modulation frequency increases for a given jet fluid velocity and entrainment section width, the angle that the jet stream makes with the long axis of the ejector becomes steeper, and a larger fraction of the total pressure force vector becomes parallel to the direction of flow. This increases the longitudinal vector component acting on the secondary fluid, thus increasing the rate and efficiency of energy transfer from the primary to secondary fluid (see FIGS. 10 a and 10 b).
As an example, consider an exemplary ejector based on the embodiments of the present invention having a jet velocity of Mach 2, and an entrainment section dimension of 3 cm wide. If the oscillation frequency is zero (0), the jet stream progresses along the center of the ejector's long axis in essentially a straight line. In this condition, the ejector functions as a shear turbulence entrainment device because secondary fluid entrainment occurs by means of viscous turbulent shear interaction at the interfacial boundary between the two fluids. Entropy increase is large in this case because turbulent shear energy transfer is largely irreversible. If the jet modulation frequency could be made infinite (∞), an abstract adducer for this illustration, the jet stream progresses through the entrainment section perpendicular to the ejector's long axis, essentially flat-on in the direction of flow. In this condition, the ejector functions as a pressure exchange device, where the longitudinal pressure vector component is at near unity, equal to the dynamic pressure. This is so because the dynamic pressure vector is parallel to the direction of fluid flow, i.e., normal to the interfacial boundary. With this orientation, shear turbulence energy transfer is near zero, and nearly all entrainment and motivation energy exchange occurs at the interfacial boundary between the two fluids as the wave proceeds. Entropy increase is small in this case because dynamic pressure energy exchange is largely reversible. For intermediate jet modulation frequencies between zero and some practical upper limit, the longitudinal pressure vector is some fraction of the total dynamic pressure vector available for doing work, largely dependent upon jet oscillation frequency and velocity. For this example, the longitudinal vector component of a unit dynamic pressure at a jet modulation frequency of 8 kHz is on the order of 0.51, and at 16 kHz, approximately 0.77. Hence, at a modulation frequency of 8 kHz, approximately 51% of the total dynamic pressure available is doing work on the secondary fluid and at 16 kHz, about 77% of the available dynamic pressure is doing useful work on the secondary fluid. In the general case with all other variables consistent, higher frequency jet modulation results in greater mass entrainment and higher compression at a lower increase in entropy. Together with the increase in surface area of the fluid jet afforded by the nozzle's high aspect ratio, mass entrainment, compression, and energy transfer are further improved. This novel method of jet modulation represents a paragon in the field of ejector design and operation.
One operating artifact of the binary-fluid ejector of the embodiments of the present invention is pressure wave vibration transmitting through the throat of the ejector and into the stagnant pressure section (Refer to FIG. 8). These vibrations or pressure wave fluctuations occur at the primary jet modulation frequency, as well as various harmonics thereof. Pressure vibrations of this type naturally reflect from the first oblique or perpendicular surface encountered, such as a pipe elbow or valve in the effluent plumbing. Unmodified, these reflected pressure waves re-enter the throat section of the ejector at some discordant frequency relative to the jet modulation frequency. This results in lower energy transfer due in part to pressure energy losses associated with the dissonant impact of the two opposing wave fronts. However, this reflected acoustic vibration provides an opportunity to further improve the energy transfer between the primary and secondary fluid. The pressure wave artifacts can be made to reflect from a solid bulkhead or open grid strategically placed in the path of the effluent at some fraction (or multiple) of the jet modulation wavelength. These reflected pressure waves will travel against the predominant flow, back towards the throat section of the ejector. When properly located, the bulkhead or grid will incite an acoustic standing wave in the pressure stagnation section of the ejector. If accurately tuned, this standing wave sympathetically concords with the primary pressure waves generated by the modulated jet, thus causing a condition of acoustic resonance in the throat section of the ejector. At resonance, the reflected pressure waves are responsive to the primary waves, thus enhancing compression and energy transfer.
As one method of use, the embodiments of the present invention can be made integral to a binary-fluid ejector refrigeration cycle as shown by example but not limited to the circuit 25 depicted in FIG. 11. In this type of system, an ejector replaces the mechanical compressor of a typical reverse-Rankine type refrigeration cycle. In this special case, the two fluids making up the binary working fluid are optimized to favor a high coefficient of thermal performance for the refrigeration cycle, without regard for how they may function in the binary-fluid ejector. Once the binary working fluid is selected or otherwise formulated, the binary-fluid ejector can be designed thereafter, consistent with the material properties of the two fluids selected. The self-consistent nature of the binary-fluid ejector of the embodiments of the present invention provides for this novel design philosophy in a manner unavailable to binary-fluid refrigeration systems employing conventional ejectors. There is an important distinction to be made between a binary-fluid ejector and a traditional ejector simply presented with a binary working fluid and called upon to operate therewith. Equally important is the distinction between an ejector dedicated to binary-fluid operation, and two fluids selected or otherwise formulated to optimize the performance of an ejector, and then simply called upon to operate in a binary-fluid refrigeration cycle. The engineering criteria used to select or otherwise formulate a binary fluid to favor performance of a refrigeration cycle versus performance of an ejector are counter-indicating. This conflict is intrinsically resolved by the embodiments of the present invention because it is a binary-fluid device deictic with regard to the material properties of the two component fluids, not the other way around.
Other variations, embodiments and features of the present invention will become evident from the following detailed description, drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram categorizing prior art ejector or jet pump technology according to principles of operation;

FIG. 2 shows a simplified functional diagram of a typical shear turbulence entrainment type ejector taught by the prior art;

FIG. 3 is an expanded block diagram categorizing prior art ejector or jet pump technology and in comparison to the embodiments of the present invention according to principles of operation;

FIG. 4 depicts a typical single-fluid type ejector refrigeration cycle consistent with much of the prior art;

FIG. 5 details the cross-sectional top view of a simplified, exemplary jet nozzle for the purpose of teaching the art of high aspect ratio nozzle design according to the embodiments of the present invention;

FIG. 6 details section A-A from FIG. 5 showing a cross-sectional end view of the simplified, exemplary jet nozzle for the purpose of teaching the art of high aspect ratio nozzle design according to the embodiments of the present invention;

FIGS. 7 a and 7 b depict a simplified representation of jet fluid isochronal serpentine geometry for the purpose of teaching the art of modulated jet technology by means of bilateral reciprocation of the primary fluid jet according to the embodiments of the present invention with FIG. 7 a showing a top view of jet fluid isochronal serpentine geometry and FIG. 7 b showing a side view;

FIG. 8 depicts a simplified representation of a binary-fluid ejector according to the embodiments of the present invention for the purpose of teaching the art of ejector body geometry, modulated fluid jet geometry, location of the primary fluid jet nozzle, and novel secondary fluid entrainment action;

FIG. 9 depicts a simplified representation of a binary-fluid ejector according to the embodiments of the present invention for the purpose of teaching the art of its novel cross-sectional geometry;

FIGS. 10 a and 10 b depict a simplified representation of high frequency jet modulation versus low frequency jet modulation for the purpose of teaching the art of bilateral reciprocating jet as a means to produce isochronal serpentine geometry in the fluid jet, and to demonstrate its benefits to secondary fluid entrainment efficiency, mass entrainment, and compression functions according to the embodiments of the present invention; and

FIG. 11 shows a binary-fluid ejector refrigeration circuit depicting an integral binary-fluid ejector for the purpose of teaching one method of use according to the embodiments of the present invention.

DETAILED DESCRIPTION

It will be appreciated by those of ordinary skill in the art that the invention can be embodied in other specific forms without departing from the spirit or essential character thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restrictive.
The embodiments of the present invention are directed to an ejector representing a new class of direct energy exchange jet pump having a function that is self-consistent for operation with dissimilar fluids representing a novel principle of operation. The seminal distinction is this regard is how the primary fluid is differentiated from the secondary fluid. If the fluids are differentiated by phase and state, then the engineering criteria for ejector design are necessarily equations of phase and equations of state, the terms of which pertain to the subject fluid. If the primary fluid is differentiated from the secondary fluid by type or kind, then the engineering criteria for ejector design are necessarily two sets of equations of phase and equations of state, the terms of which pertain to two different fluids. Therefore, we introduce a division in the principles of operation for ejectors based on primary versus secondary fluid differentiation, namely doublet fluid versus binary fluid.
FIG. 1 is a block diagram 5 which categorizes prior art fluid ejectors based on principals of operation. FIG. 3 is a block diagram 10 which categorizes prior art along with the embodiments of the present invention based on principles of operation. Note that some principles of operation are common to all types of gas-phase ejectors. For example, direct energy transfer via intimate fluid contact 6 is universal to all gas-phase jet pump devices. Also note that all gas-phase ejector devices exploit the fluid dynamic transform between high velocity dynamic pressure 7 and low velocity static pressure as a means for secondary fluid compression. One class of ejector will not function properly using a principle of operation from another class, unless that principle is common to both. For example, a pressure exchange type ejector such as taught by U.S. Pat. No. 6,308,740 to Smith, et al requires an unsteady state primary jet in order to operate. In such a case, the jet is modulated in the time domain as a regular series of pulses at some frequency. Note in FIG. 3 that unsteady state primary jet is an operating principle requisite for pressure exchange type ejectors. If a steady state primary jet were used to drive Smith's device, it would not operate properly or possibly not at all.
The embodiments of the present invention relate to a binary fluid device 8 which will not operate properly using a doublet fluid. In turn, traditional gas-phase ejectors are doublet fluid devices which will not operate properly using a binary fluid, despite the fact that some have been put to the task in binary fluid refrigeration cycles. It is known that two fluids intended for binary fluid vocation may be selected or otherwise formulated to improve ejector performance, such as taught by U.S. Pat. No. 4,761,970 to MacCracken. However, the reverse has not been taught. That is, an ejector dedicated to the vocation of binary-fluid operation. Hence, we introduce the embodiments of the present invention as a binary-fluid type ejector, distinct by the nature of its unique principle of operation. FIG. 2 shows a prior art momentum energy exchange Ejector 15 and FIG. 4 shows a prior art doublet-fluid ejector refrigeration cycle 20.
FIGS. 5 and 6 show the cross-sectional top and end view of a simplified, exemplary jet nozzle 100 for the purpose of teaching the art of high aspect ratio nozzle design of the embodiments of the present invention. As with all jet nozzles, a source of high-pressure fluid is introduced at an inlet 101, flow is then restricted through a throat 104 having a smaller cross-sectional area than the inlet, and then discharged at outlet 102 that is often flared to a slightly larger cross-sectional area than the throat 104. The nozzle 100 depicted in FIGS. 5 and 6 is intended to show generic features, otherwise unremarkable except for certain dimensional relationships to be made clear below. For both turbulence and pressure exchange type devices, the surface to volume ratio of the primary fluid jet plays a critical role in ejector performance and efficiency. This is so because for either ejector type, energy transfer and secondary fluid entrainment are dynamic processes occurring at the interfacial boundary between the primary and secondary fluids. For any given interface boundary area, the rate of mass entrainment cannot be improved by increasing the mass or volume of fluid resident some distance from the boundary itself, that is, fluid that is positioned in the jet stream distant from the interfacial boundary can exert little or no effect on the secondary fluid. Contact between the primary and secondary fluid is a requisite for turbulent or pressure energy exchange, a subtle but powerful observation to be understood in the context of the embodiments of the present invention.
Another equally important observation pertinent to this art is the fact that per unit length, the surface to volume ratio of a fluid jet with a circular cross-section is fixed for any given cross-sectional area. The same is true for the cross-sectional geometry of a square, triangle, or any regular polygon except a rectangle. By contrast, the surface to volume ratio per unit length of a jet stream with a unit cross-sectional rectangle shape can be any number greater than four (4) depending on its aspect ratio, practical upper limits notwithstanding. This also applies to any cross-sectional geometry approximating a rectangle, such as the one shown in FIG. 6 at 112, or an ellipse with large eccentricity. Therefore, for any given jet stream length and cross-sectional area, any rectangle with an aspect ratio greater than one (1) will have a larger surface to volume ratio than the geometry of a circle, square, or any regular polygon except a triangle. For this reason, and because energy is transferred from the primary to secondary fluid at the interfacial boundary separating the two, the embodiments of the present invention are directed to a high aspect ratio jet nozzle.
FIG. 6 is section A-A from FIG. 5 near the axis of rotation 103 showing nozzle throat rectangular geometry 112 with a high aspect ratio. A high aspect ratio is any dimensional ratio h/w greater than one (1), h/w>1, where h is indicated at 113 and w at 114. The view of the throat 111 is against the direction of flow, towards the nozzle inlet 101. Note that the cross-sectional shape of the nozzle throat 111 is not a perfect rectangle. In the example shown, it has slightly rounded ends at 115. In the context of the embodiments of the present invention, it is not necessary for the cross-sectional shape of the nozzle throat 111 to be a perfect rectangle, only that its general dimensions h 113 and w 114 obey the rule h/w>1, thus qualifying it as having a high aspect ratio. For example, a very eccentric ellipse qualifies, that is, an ellipse with a small minor axis with respect to its major axis. In addition, the walls 112 of the nozzle throat 111 need not be flat or parallel. The walls 112 may be concave, convex, or some irregular shape with respect to each other. This novel throat geometry increases the surface area of the jet stream for any given primary fluid mass flow rate, therefore increasing the rate of energy transfer to the secondary fluid.
Consider the circular cross-sectional shape of conventional fluid jets compared to the high aspect ratio rectangular shaped jet of the embodiments of the present invention. Referring to FIGS. 5 and 6, which depict simplified, exemplary representations of the jet nozzle of the embodiments of the present invention, the aspect ratio of the jet nozzle throat, as well as the fluid jet discharged from it, is defined as:
$\begin{matrix} β \equiv \frac{h}{w} & (4) \end{matrix}$
where h and w denote the cross sectional dimensions of the throat or jet stream as height and width respectively. Surface to volume ratio φ for a unit length is numerically equivalent to perimeter to cross-sectional area ratio, and is defined here as:
$\begin{matrix} φ \equiv \frac{p}{a} & (5) \end{matrix}$
where p and a denote perimeter and cross sectional area respectively.
For a circular cross section jet nozzle throat or fluid jet:
$\begin{matrix} φ_{c} = \frac{p_{c}}{a_{c}} = \frac{2 π r_{c}}{π r_{c}^{2}} = \frac{2}{r_{c}} & (6) \end{matrix}$
where r is radius and subscript c denotes circular. In turn, the ratio for a rectangular cross section jet nozzle throat or fluid jet is given by:
$\begin{matrix} φ_{r} = \frac{p_{r}}{a_{r}} = \frac{2 (h + w)}{hw} & (7) \end{matrix}$
where h and w are as before, and subscript r denotes rectangle. In the case of a rectangle with an aspect ratio of 1, β=1, which of course is a square where h=w, its perimeter is always greater than a circle of the same area, i.e. where a_r=a_c. Thus:
φ_r>φ_c (8)
for any value of a. In order to compare equations (6) and (7) numerically, equation (6) is recast in common terms as equivalent radius r_r:
$\begin{matrix} r_{r} = {(\frac{a_{r}}{π})}^{0.5} = {(\frac{hw}{π})}^{0.5} & (9) \end{matrix}$
where r_ris the equivalent radius of a rectangle if its area were reshaped as a circle. Substituting r_rfor r_cin equation (6), equation (8) can be rewritten with common terms for the purpose of numerical comparison:
$\begin{matrix} \Rightarrow \frac{2 (h + w)}{hw} > \frac{2}{{(\frac{hw}{π})}^{0.5}} & (10) \end{matrix}$
For a unit area, a=1, where h=w corresponds to an aspect ratio β of 1, equation (10) has the following solution:
$\Rightarrow \frac{2 (1 + 1)}{1} > \frac{2 \sqrt{π}}{1} \Rightarrow 4 > 3.54,$
where φ_r=4 and φ_c=3.54, indicating that for any common value of a, the perimeter of a rectangle with an aspect ratio of 1 is always greater than a circle. For the purpose of this disclosure, the term “high aspect ratio,” as applied to the nozzle or the fluid jet itself, means any value of β greater than one, i.e. β>1. Using equivalent identities for h and w as defined by the equations for a and β, the terms h and w are substituted by a and β in equations (6) and (7), thus:
$\begin{matrix} \Rightarrow φ_{c} = \frac{2 π^{0.5}}{a^{0.5}} and : & (6 a) \\ \Rightarrow φ_{r} = \frac{2 [{(β a)}^{0.5} + {(a / β)}^{0.5}]}{a} & (7 a) \end{matrix}$
Therefore, for a given throat area a and aspect ratio β equations (6a) and (7a) predict the surface to area ratio φ for circular and rectangular nozzle geometries. The following table shows values of φ_rand φ_ccorresponding to selected aspect ratios. Note that for the values of β considered, nozzle throat area a has been normalized to a value of one (1) as a means for numerical comparison.

TABLE 1

		p to a	p to a
Nozzle		Ratio	Ratio
Throat	Aspect	Rectangle	Circle
Area a	Ratio β	φ_r	φ_c	Advantage %

1	1	4.00	3.54	13
1	2	4.24	3.54	20
1	3	4.62	3.54	30
1	5	5.37	3.54	51
1	7	6.05	3.54	71
1	10	6.96	3.54	96

As clearly demonstrated, the rectangular nozzle geometry of the embodiments of the present invention is superior to traditional circular nozzle geometry, even for the modest aspect ratios considered. The greater surface to volume ratio of a high aspect ratio primary fluid jet translates directly to significant improvement in mass entrainment ratio, compression ratio and energy transfer between the primary and secondary fluids. This is true because for a pressure exchange type ejector, energy is transferred from the primary to secondary fluid at the interfacial boundary separating the two fluids. Consequently, for a given mass flow rate, a greater interfacial surface area will result in a higher energy transfer rate. Accordingly, energy efficiency and pumping performance are greatly increased over conventional ejector designs.
FIGS. 7 a and 7 b depict a simplified representation of jet stream isochronal serpentine geometry for the purpose of teaching the novel art of jet modulation by means of bilateral reciprocation of the primary fluid jet. FIG. 7 a shows a top view of a jet stream isochronal serpentine geometry while FIG. 7 b shows a side view. By necessity, the fluid jet of a pressure energy exchange type gas-phase ejector is modulated. In the case of the embodiments of the present invention, it is modulated in the spatial domain as opposed to the time domain, that is, instead of being pulsed at a frequency, the jet stream is spatially oscillated from side to side or up and down at a frequency, thereby alternately transecting the entrainment section forming a serpentine flow pattern as shown. This wave action is best described as bilateral reciprocation. The geometry is isochronal because the interstice between successively formed wave fronts occurs at regular intervals. The wave action can be produced by mechanically oscillating the jet nozzle in reciprocal fashion through an angle of arc, by non-mechanical means such as by a fluidic oscillator having no moving parts, by means of a piezo-fluidic oscillator having a piezoelectric vibrating reed superposed in the jet stream, or by other means. The isochronal serpentine geometry shown in FIG. 7 a is highly simplified as it does not depict fluid turbulence or the eventual loss of continuity that would certainly occur as the primary fluid intermingles with the secondary fluid. The shape is depicted in this highly stylized form as an aid for understanding the spatial nature of this type of jet modulation. In FIG. 7 a, the primary fluid jet issues from the jet nozzle 120, then proceeds as shown from area 121 towards the effluent end 123 of the ejector. FIG. 7 b depicts the same fluid motion as viewed from the side-note the high aspect ratio jet nozzle 127. During its lengthwise traverse, the jet stream velocity decreases while static pressure increases as indicated by the directional arrows 124. The jet stream at 121 has a high velocity, a high dynamic pressure and a low static pressure. As the jet stream progresses towards the effluent end 123 of the ejector, high velocity kinetic energy is converted to low velocity potential energy in the form of a local increase in static pressure. Any secondary fluid 126 entrained directly by the jet stream or braided there between by supervening pressure waves is thereby motivated and subsequently compressed. Although the frequency of the modulated jet stream remains relatively constant over the length of the ejector, the wavelength shrinks owing to compression. The width of the jet stream w 125 and its height h 129 correspond to the width w 113 and height h 114 of the jet nozzle throat 111 depicted in FIG. 6. Consequently, the cross-sectional geometry of the jet stream reflects the high aspect ratio character of the jet nozzle 110 (FIG. 6). In three dimensions, it may be modeled as a thin wavy ribbon.
FIG. 8 depicts a simplified representation of a binary-fluid ejector of the embodiments of the present invention for the purpose of teaching the art of ejector body geometry, modulated fluid jet geometry, location of the primary fluid jet nozzle and secondary fluid entrainment action. For the purpose of discussion, the ejector 130 can be divided into general sections such as entrainment 131, compression 132, and pressure stagnation 133; however, entrainment, mixing, diffusion, and compression should be considered concatenated processes with rather broad transition zones there between. High-pressure primary fluid issues from the jet nozzle 134 at high velocity. In the case of this example, the high aspect ratio nozzle 134 is mechanically rotated about axis 135 through an angle of arc in a side-to-side reciprocating fashion. In other embodiments, jet modulation may be accomplished by means of a fluidic oscillator with no moving parts, or by other means. The jet stream 138 is thereby modulated by means of bilateral reciprocation, which causes the jet stream 138 to form the isochronal serpentine geometry as shown. As the jet stream 138 progresses towards the effluent end of the ejector generally, its modulation frequency remains quasi-constant while its wavelength diminishes due to fluid compression. Over the same course, jet stream velocity decreases as energy is transferred to the entrained secondary fluid while kinetic energy is converted to potential energy in the form of a local increase in static pressure in the general area of 133 shown in FIG. 8.
In the context of ejector body geometry, it is important to consider that energy transfer efficiency is directly proportional to the surface to volume ratio of the high aspect ratio jet stream. This understanding provides a cognitive trajectory that points to a singular conclusion: the cross-sectional shape of the ejector body should be a congener of jet stream geometry in its oscillating form. Thus, the ejector body of the embodiments of the present invention comprises such geometry. Referring to FIG. 9, note that the cross-sectional shape of the ejector body 150 is not round, but rather rectangular. Sections A-A 151, B-B 152, and C-C 153 correspond to the top and side views 150. This unique ejector body geometry is intentionally fitted to the cross-sectional geometry of the fluid jet as it oscillates. The rotational axis 156 of the jet nozzle 154 is positioned to intersect the long axis 157 of the ejector. Note in the side view that the nozzle throat 155 extends from the inside bottom to the inside top of the ejector body corresponding to height h 158, which in turn corresponds to the height h 113 of the nozzle throat 111 in FIG. 6, and the height h 129 of the fluid jet itself in FIG. 7 b. This nozzle placement puts the fluid jet itself in a position where it extends from the inside bottom to the inside top of the ejector body. Since the fluid jet is in close proximity to the bottom and top inside walls, it attaches itself to the walls by action of the Coand{hacek over (a)} effect. Now returning to FIG. 8, note that as the jet stream reciprocates, it also alternately attaches itself to the side walls of the ejector in the general area of the contact points L 136 and R 136. The jet stream 138 remains attached to the inside of each of the four walls of the ejector body at least one wavelength distance from the nozzle outlet 134. In one embodiment, the inside walls of the ejector are made very flat and highly polished as a means to facilitate jet fluid attachment. Secondary fluid enters the entrainment section on either side of the jet nozzle at 137. As the nozzle or jet reciprocates from side to side, secondary fluid is drawn forward by action of low static pressure generated by the high velocity jet. As secondary fluid flows around the jet nozzle, edge-tone turbulence is produced causing alternate billows of rotating secondary fluid to move into the general area of 137 a. The fluid in this area is then enveloped by the following jet stream wave, thus braiding a volume of secondary fluid within the pressure wave and the ejector wall in the area of 137 b. The braided secondary fluid in the general area of 137 c then proceeds towards the ejector throat 139 as the primary fluid expands and the secondary fluid is compressed. Secondary fluid compression occurs in successive periods at the same frequency as the jet modulation, and is consequently peristaltic in nature. This method of secondary fluid entrainment and compression is unique in the field of ejectors and jet pumps.
In the context of braiding secondary fluid within supervening pressure wave fronts, a method of fluid entrainment unique to the embodiments of the present invention is disclosed. Thus, fluid manipulation is largely possible because the fluid jet is attached to the four inside walls of the ejector body by action of the Coand{hacek over (a)} effect. Conventional pressure exchange type ejector design imparts primary jet pressure waves to the secondary fluid by means of periodic jet pulses or continuously rotating fluid jets. For these and other methods, the fluid pulse or rotating jet(s) is/are presented to the body of the secondary fluid with no means of containment. In the case of a pulsating fluid jet, a billow of fluid is discharged from the jet nozzle into the entrainment section of the ejector body. Although a certain fraction of the pulsed pressure wave front exerts a dynamic force on the secondary fluid, a great deal of secondary fluid is free to slip around the bolus of high velocity primary fluid. In the case of rotating fluid jets, no attachment is provided or caused to occur between the rotating jets and the inside body of the entrainment section of the ejector. As a result, as in the pulsed jet case, secondary fluid is free to slip or otherwise escape around the fluid jets at they rotate. By contrast, due to the unique body geometry of the embodiments of the present invention that is purposefully matched to the cross-sectional geometry of the serpentine primary fluid jet, and to its dimensions that extend from the inside bottom to inside top of the ejector body, the primary fluid jet attaches to each of the four inside walls of the ejector. This provides a means to trap or otherwise contain the secondary fluid within the interstices of successive fluid pressure waves, hence braiding secondary fluid there between. This method of secondary fluid entrainment is unique, and coined herein as braiding.
FIGS. 10 a and 10 b depict a simplified, exemplary representation of high frequency jet modulation versus low frequency jet modulation for the purpose of teaching the art of bilateral reciprocating jet as a means to produce isochronal serpentine geometry in the fluid jet, and to demonstrate its benefits to secondary fluid entrainment efficiency, mass entrainment and compression. The jet modulation frequency has an effect on the rate of energy transfer from the primary to secondary fluid. Within certain limits, a higher modulation frequency results in a greater energy transfer rate, as well as greater energy transfer efficiency. The embodiments of the present invention are directed to a pressure exchange type ejector, that is, it employs dynamic pressure as a means for secondary fluid entrainment as opposed to shear turbulence. Ejectors of this type rely on a high velocity fluid wave front to transfer energy to a secondary fluid for the purpose of pumping and compressing that fluid. Motivation, entrainment and compression occur at the interfacial boundary between this wave front and the secondary fluid. By action of the jet's momentum, this wave front presents a dynamic force to the secondary fluid in the form of a pressure vector (force per unit area). As the wave front attempts to travel through or otherwise displace the body of the secondary fluid, momentum is exchanged by action of molecular collision: the primary fluid loses momentum, while the secondary fluid gains momentum. The magnitude of this pressure vector is proportional to the differential velocity between the primary and secondary fluid, the former much higher than the latter, fluid density, and the difference in molecular mass between the two fluids. In one embodiment, the primary fluid has a greater molecular mass than the secondary fluid.
Since the dynamic pressure is hydraulic in nature, its vector is always normal to the interfacial boundary between the primary and secondary fluids regardless of the conditions present. The vector component of the dynamic pressure that is parallel with the direction of flow at the interfacial boundary is the operative agent for energy transfer and is called the “longitudinal component.” The direction of flow in this context is always from the jet nozzle towards the effluent end of the ejector parallel with the long axis (157 in FIG. 9) of the ejector body. The vector component of the dynamic pressure that is perpendicular to the direction of flow at the interfacial boundary is incapable of energy transfer and is called the “transverse component.” It is important to understand that the serpentine shape of the jet stream is not sinusoidal. The wave shape is roughly triangular, but the sidewalls of the ejector body are asymptotic with respect to the wave crests or peaks. This is so because properly modulated, the transverse path of the jet stream has a constant spatial gradient. As a result, a large part of the wave front is rather flat, and is taken as such for this exam. Referring to FIG. 10 b, note the angle θ at 149. This is a measure of the angle that the wave front makes with a line perpendicular to the direction of flow, which is indicated by the arrows at 147. The angle θ varies with the modulation frequency: as the frequency increases, θ approaches zero. At a modulation frequency of zero, i.e., no modulation, the jet stream flows steady state down the center axis of the ejector parallel with the direction of flow, and θ would equal π radians. In this case, the transverse vector component 142 is at unity, equal to the magnitude of the pressure vector 141, and the longitudinal vector component 142 is zero. In this condition, all secondary fluid entrainment occurs by action of shear turbulence along the interfacial boundary of the primary fluid jet and the secondary fluid; dynamic pressure entrainment would be zero.
If the modulation frequency could be made infinite, the wave front would become perpendicular to the general direction of flow, and θ would equal 0 radians. In this case, the transverse component 142 would be zero, and the longitudinal component 143 would be at unity, equal to the magnitude of the dynamic pressure vector 141. In this condition, all secondary fluid entrainment would occur by action of dynamic pressure over the interfacial boundary area; shear turbulence entrainment would be zero.
For intermediate modulation frequencies between zero and some practical upper limit, the magnitude of the longitudinal vector component is proportional to the cosine of the angle θ. Hence, within certain limits, higher modulation frequencies produce greater longitudinal vector components, resulting in higher rates of energy transfer between the primary and secondary fluid, as well as much greater secondary fluid mass entrainment.
FIG. 10 a depicts the relative size of the longitudinal versus transverse vector components for a modulation frequency having a γ wavelength 140. FIG. 10 b depicts the same relative comparison for a modulation frequency having a 2λ wavelength 148. The longitudinal vector component is larger in the higher frequency case. The comparison is qualitative.
Using this construct, the magnitude of the longitudinal force Λ as a function of modulation frequency may be predicted by:
$\begin{matrix} Λ (f) = \cos (\tan^{- 1} \frac{v}{2 fx}) & (11) \end{matrix}$
where v is jet stream velocity [m/s] (not Mach number), f is modulation frequency [Hz], and x denotes the width of the entrainment section of the ejector body [m].
The primary to secondary fluid energy conversion efficiency is directly proportional to Λ.
Table 2 shows values of Λ for selected values of f and v. The value of x is normalized to 3.0E⁻02 m as a means to provide a numerical comparison between f and v:

	TABLE 2

	Initial Jet Stream	Jet Modulation Frequency in kHz

Mach Number

4	8	12	16	20

0.5	0.77	0.92	0.96	0.98	0.99
1.5	0.37	0.62	0.77	0.85	0.89
2.0	0.29	0.51	0.67	0.77	0.83
2.5	0.23	0.43	0.58	0.69	0.77

It is obvious from equation (11) and the sample data in Table 2 that higher jet stream velocity requires higher modulation rates for a given energy conversion efficiency.
A numerical exam is presented as an example of one method of use for the embodiments of the present invention integral to a binary fluid refrigeration cycle. Standard air conditioning systems used for residential cooling are relatively constant rate machines. Except for the liquid expansion valve, which is passively modulated by evaporation temperature, the two fans and the compressor are not actively variable, although motor consumption does vary with heat load and outside air temperature to some extent. This means that the system operates at near full output capacity regardless of the heat load in the space. Traditional air conditioning systems manage heat load against refrigeration output by cycling on and off, thus oscillating on either side of the thermostat temperature set point. During hot weather, a traditional reverse-Rankine system cycles more frequently and runs for longer periods per “on” cycle. A binary-fluid refrigeration system driven by solar energy (for example) would best function on a fundamentally different basis. Such a system would vary its refrigeration output as a function of presented heat load because solar energy varies over time, generally having a higher energy density at higher air temperatures and vice versa (this, notwithstanding cloud cover and night, which can skew this relationship somewhat). If uncontrolled, this variable thermal input, solar isolation in this case, will cause boiler pressure, condenser pressure, ejector mass entrainment and secondary fluid compression to vary responsively. This implies that a binary-fluid ejector refrigeration system integral with the embodiments of the present invention would best operate on a continuous basis, matching its refrigeration output with the space heat load and the available energy from the heat source. For traditional ejectors, this represents an engineering challenge because optimum ejector performance is narrow with respect to the differential pressures across the ejector. This is the case for the differential pressure across the jet nozzle as well as the difference between the evaporation and condensing pressures. However, in the case of the of the embodiments of the present invention, jet modulation frequency may be easily varied to continually track variations in the heat supply and heat load from the space, doing so as a means to manage the resultant variations in differential pressure across the jet nozzle, mass entrainment ratio and secondary fluid compression. Consequently, the thermal and fluidic performance of the binary fluid ejector may be substantially optimized for any input condition as they may vary.
For this example, the following assumptions are made:
1. 760 W/m²solar isolation;
2. solar absorption efficiency: 65%;
3. available thermal energy from collector/boiler: 494 W/m²(0.65×760 W/m²);
4. outside air temperature: 37° C.;
5. inside air temperature set point: 24° C.;
6. heat load under above conditions: 16.5 kW (4.7 tons);
7. average US house size 2006: 218.3 m²; (2,349 ft²);
8. the value of ω=0.2;
9. primary motive fluid: perfluorocarbon; and
10. secondary refrigerant fluid: water.
One leading criterion for selecting two fluids in a binary-fluid refrigeration cycle as a means to improve COP is to maximize the difference between the phase change enthalpy of the primary fluid versus the secondary fluid. The secondary refrigerant fluid having a higher phase change enthalpy Δh_vthan that of the primary motive fluid. In the present example, water is used as the secondary refrigerant fluid, and perfluorocarbon is used as the primary motive fluid, having values of Δh_vof ˜2,500 kj/kg and ˜89 kj/kg, respectively. This translates to an overall COP of 5.1, requiring a solar collector just 6 meters square (2.5 meters on a side), occupying only 2.6% of the available roof area for this example. This represents a formidable and significant improvement over doublet and binary-fluid ejector systems taught by the prior art, or currently available in the industry.
Countless other applications for the binary fluid ejector and method of use as described herein are conceivable.
Although the invention has been described in detail with reference to several embodiments, additional variations and modifications exist within the scope and spirit of the invention as described and defined in the following claims.

Claims

1. A binary fluid ejector comprising:

an ejector body defining an inlet, an outlet and a throat between said inlet and outlet, said ejector body operable to receive a primary fluid and secondary fluid; and

a jet nozzle configured to discharge said primary fluid, said jet nozzle having an aspect ratio greater than one.

2. The binary fluid ejector of claim 1 wherein said jet nozzle has a substantially rectangular or elliptical cross section.

3. The binary fluid ejector of claim 1 wherein one or more of said inlet, throat and outlet has a substantially rectangular or elliptical cross section.

4. The binary fluid ejector of claim 1 wherein said ejector body has dimensions and a cross-sectional shape consistent with dimensions and shape of a primary fluid jet stream.

5. The binary fluid ejector of claim 1 wherein said jet nozzle is configured to oscillate.

6. The binary fluid ejector of claim 1 wherein said primary fluid and secondary fluid are dissimilar in chemical composition, or material property except phase or state.

7. The binary fluid ejector of claim 1 wherein said primary fluid is either in a gas state or saturated vapor state and said secondary fluid is in a gas state or saturated vapor state.

8. A binary fluid ejector system comprising:

an ejector body defining an inlet, an outlet and a throat between said inlet and outlet:

a jet nozzle configured to discharge a primary fluid in an oscillating manner within said ejector body, said jet nozzle having an aspect ratio greater than one; and

a secondary fluid source configured to discharge a secondary fluid into said ejector body.

9. The binary fluid ejector system of claim 8 wherein said jet nozzle is oscillated via mechanical means.

10. The binary fluid ejector system of claim 8 wherein said jet nozzle is oscillated via a fluidic oscillator.

11. The binary fluid ejector system of claim 8 wherein said jet nozzle is oscillated via a piezo-fluidic oscillator.

12. The binary fluid ejector system of claim 8 wherein said jet nozzle oscillates at a fixed frequency.

13. The binary fluid ejector system of claim 8 wherein said primary fluid is in a gas or saturated vapor state.

14. The binary fluid ejector system of claim 8 wherein said secondary fluid is in a gas or saturated vapor state.

15. The binary fluid ejector system of claim 8 wherein said primary fluid and secondary fluid are dissimilar in chemical composition, or material property except phase or state.

16. A method of operating a binary fluid ejector comprising:

discharging a primary fluid and a secondary fluid into an ejector body defining an inlet, an outlet and a throat between said inlet and outlet; and

wherein said primary fluid is discharged through a jet nozzle having an aspect ratio greater than one.

17. The method of claim 16 further comprising arranging the ejector body and the primary fluid jet stream sufficiently proximal to cause primary fluid jet stream wall attachment.

18. The method of claim 16 further comprising configuring said jet nozzle to have a substantially rectangular or elliptical cross section.

19. The method of claim 16 further comprising configuring one or more of said inlet, throat and outlet to has a substantially rectangular or elliptical cross section.

20. The method of claim 16 further comprising configuring said ejector body to have dimensions and a cross-sectional shape consistent with dimensions and shape of a primary fluid jet stream.

21. The method of claim 16 further comprising discharging said primary fluid through said jet nozzle in an oscillating manner.

22. The method of claim 21 further comprising utilizing mechanical means, fluidic oscillator or a piezo-fluidic oscillator.

23. The method of claim 21 further comprising discharging said primary fluid in an oscillating manner at a fixed frequency.

24. The method of claim 16 further comprising discharging said primary fluid and secondary fluid in a gas or saturated vapor state.

25. The method of claim 16 further comprising utilizing a primary fluid and secondary fluid dissimilar in chemical composition, or material property except phase or state.

26. A binary fluid ejector comprising:

an ejector body defining an inlet, an outlet and a throat between said inlet and outlet wherein one or more of said inlet, throat and outlet is rectangular or elliptical in cross section.

27. A refrigeration system comprising:

a binary fluid ejector having a body defining an inlet, throat, outlet and nozzle jet wherein said nozzle jet has an aspect ratio greater than one;

a fractioning condenser;

boiler;

evaporator;

expansion valve; and

wherein said binary fluid ejector is configured to receive boiler gas and saturated vapor from the evaporator, said binary fluid ejector further configured to discharge a gas comprising said boiler gas and saturated vapor from said evaporator.

28. The refrigeration system of claim 27 further comprising a gravity pump.