Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
  • F01C11/00—Combinations of two or more machines or engines, each being of rotary-piston or oscillating-piston type
  • F01C11/002—Combinations of two or more machines or engines, each being of rotary-piston or oscillating-piston type of similar working principle
  • F01C11/004—Combinations of two or more machines or engines, each being of rotary-piston or oscillating-piston type of similar working principle and of complementary function, e.g. internal combustion engine with supercharger
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
  • F01C1/00—Rotary-piston machines or engines
  • F01C1/08—Rotary-piston machines or engines of intermeshing engagement type, i.e. with engagement of co- operating members similar to that of toothed gearing
  • F01C1/12—Rotary-piston machines or engines of intermeshing engagement type, i.e. with engagement of co- operating members similar to that of toothed gearing of other than internal-axis type
  • F01C1/123—Rotary-piston machines or engines of intermeshing engagement type, i.e. with engagement of co- operating members similar to that of toothed gearing of other than internal-axis type with tooth-like elements, extending generally radially from the rotor body cooperating with recesses in the other rotor, e.g. one tooth
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
  • F01C1/00—Rotary-piston machines or engines
  • F01C1/08—Rotary-piston machines or engines of intermeshing engagement type, i.e. with engagement of co- operating members similar to that of toothed gearing
  • F01C1/12—Rotary-piston machines or engines of intermeshing engagement type, i.e. with engagement of co- operating members similar to that of toothed gearing of other than internal-axis type
  • F01C1/14—Rotary-piston machines or engines of intermeshing engagement type, i.e. with engagement of co- operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
  • F01C1/16—Rotary-piston machines or engines of intermeshing engagement type, i.e. with engagement of co- operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with helical teeth, e.g. chevron-shaped, screw type
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01C—ROTARY-PISTON OR OSCILLATING-PISTON MACHINES OR ENGINES
  • F01C1/00—Rotary-piston machines or engines
  • F01C1/08—Rotary-piston machines or engines of intermeshing engagement type, i.e. with engagement of co- operating members similar to that of toothed gearing
  • F01C1/12—Rotary-piston machines or engines of intermeshing engagement type, i.e. with engagement of co- operating members similar to that of toothed gearing of other than internal-axis type
  • F01C1/14—Rotary-piston machines or engines of intermeshing engagement type, i.e. with engagement of co- operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
  • F01C1/20—Rotary-piston machines or engines of intermeshing engagement type, i.e. with engagement of co- operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with dissimilar tooth forms

Definitions

• the present invention relates to a rotary device and a method of operating a rotary device.
• the present invention comprises developments of the methods and apparatuses described in the published patent application WO-A-91/06747 and granted patents US-B-6168385 and US-B-6176695 the entire contents of which are hereby incorporated by reference.
• Detonation is a process in which a gaseous mixture of a fuel distributed in air or oxygen undergoes oxidation with consequent release of heat in a more rapid manner than that which occurs in flame-induced combustion or deflagration.
• the detonation is usually started by an ignition of the air/fuel mixture.
• Detonation of an air/fuel mixture causes the generation of a shock wave, as a result of the expansion of the air/fuel mixture due to the heat generated by the process.
• the shock wave passes through the gaseous mixture (charge gases) travelling at a much greater velocity than is possible for a flame during deflagration and typically at Mach Numbers greater than 1.
• detonation can be made to occur in a tube having one end closed and the other open.
• a charge of fuel and air is introduced to the tube through valves or ports at the closed end where an igniter is located.
• the shock wave is initiated due to rapid expansion of the ignited air/fuel mixture at the igniter, it passes down the tube at very high velocity.
• Significant thru3t is generated as the charge gases exit the open end of the tube at high velocity as a result of the expansion caused by the heat release of detonation.
• a number of tubes may be arranged so as to form a thrust generation engine in which detonations are made to occur sequentially. See, for example, US-A-5345758 in which such a system is described.
• US-A-4741154 discloses a rotary detonation engine.
• the engine comprises detonation chambers and a number of turbine blades arranged to be driven by the detonated charge of air and fuel mixture received from the detonation chambers.
• This engine relies on a catherine-wheel effect to drive the rotor.
• the engine does not enable an efficient conversion of the energy from the detonation into rotary power.
• the turbine blades are subject to fluctuating forces from the detonation, for which they cannot perform efficient energy conversion and which renders them liable to fatigue fracture.
• a rotary device comprising: a chamber for receiving a charge of an air/fuel mixture and for oxidising the fuel by detonation; and a rotary expander having a transient chamber of variable volume, the transient chamber being in fluid communication with the detonation chamber during at least part of a cycle of rotation of the rotary expander, the rotary expander being arranged to be driven by expansion of the air/fuel mixture caused by detonation thereof.
• the invention provides a rotary device that enables rotary power to be obtained from a detonation process.
• a rotary expander is provided that provides an efficient means for extracting the power from the expanding gases generated in the rotary device.
• the invention provides a rotary device in which energy released from fuel may be converted into shaft power using the rotary expander in a manner, which offers several significant advantages when compared with Otto, Diesel and gas turbine cycle engines.
• the fuel oxidation process is initiated only after the fuel-air mixture has been compressed and has therefore already reached temperature and pressure levels which are substantially above ambient.
• the heat release upon combustion further elevates the temperature and pressure to extremely high Ievel3.
• This ha3 a number of disadvantages.
• the engine needs to be constructed of materials, which are capable of both withstanding the high thermal and physical stresses and of sealing the gas charge within the combustion chamber. Due to the high thermal and physical stress some thermal and leakage losses are inevitable during this process.
• the rotary device of the present invention suffers from none of these disadvantages. Little or no work from an external source, such as flywheel inertia, is applied to the working fluid before the fuel is oxidised. Any compression is largely or entirely locally generated in the reaction zone within the working fluid charge as a result of oxidation being achieved by detonation, i.e. by a thermo-chemicalIy derived shock wave. Consequently the pressures and temperatures throughout the engine are much lower than those in piston and gas turbine engines. The lower thermal gradients greatly reduce the potential for thermal losses .
• an external source such as flywheel inertia
• Leakage losses from the working fluid charge can also be kept to extremely low levels without the need for physical or mechanical seals because of the absence of large pressure gradients, thus avoiding the generation of internal friction losses.
• the potential energy of the fuel is converted directly into expansion of the working fluid with minimal internal losses .
• the gas expansion is converted efficiently into shaft power by the rotary expander with minimal losses during the expansion process, thus providing a rotary device of high efficiency through the reduction of internal losses.
• a method of operating a rotary device comprising a detonation chamber in fluid communication wich a transient chamber of a rotary expander, the metzho ⁇ comprising: receiving in the detonation chamber a charge of a gas/fuel mixture; and detonating said mixture to cause expansion of the gas/fuel mixture and thereby drive the rotary expander.
• Figure 1 shows schematically a perspective view of an example of a rotary device according to an embodiment of the present invention
• Figure 2 is a view of the device of Figure 1 with certain components removed for clarity;
• Figure 3 is a view of the device of Figure 1 with certain components removed for clarity;
• Figures 4A to 4H show rotor end profiles at stages through a cycle for a compressor
• Figures 5A to 5H show rotor end profiles at stages through a cycle for an expander
• Figure 6 shows a section through a port having a grid filter for use in the rotary device in Figure 1;
• Figure 7 is a graph showing the stages in a detonation cycle for the rotary device of Figure 1;
• Figure 8 shows schematically a longitudinal section view of an example of a rotary device according to an embodiment of the present invention.
• Figures 1 to 3 show part views of an example of a rotary device according to an embodiment of the present invention.
• the device comprises a compressor 2, a detonation chamber 4 and an expander 6 arranged within a housing defined by walls (not all shown) .
• the detonation chamber 4 is contained within a stator cylinder 3 to be described in more detail below.
• An intermediate wall 10 is provided to separate the compressor and the expander.
• the compressor 2 is arranged to provide a compressed charge of an air/fuel mixture to the detonation chamber 4.
• Each of the compressor 2 and expander 6 is made up of two rotors (5 and 7 for compressor; 16 and 18 for expander) arranged for counter rotation about parallel axes.
• the rotors 16 and 18 of the expander are clearly visible.
• the rotors of the expander and the intermediate wall 10 have been removed to provide a clear view of the rotors of the compressor.
• the rotors 5, 7, 16 and 18 of both the expander and the compressor are arranged within a housing of which only one end wall 8 and the intermediate wall 10 are shown in Figure 1. Further walls (not shown) are provided so that the rotors and the stator cylinder 3 about which they are arranged to rotate are enclosed.
• Openings 12 and 14 are provided in the walls of the housing.
• the openings 12 and 14 are provided to enable moveable shaped containment walls to be inserted into the rotary device.
• the containment walls shown in section in figures 4A to 4H and 5A to 5H) enable the maximum possible volumes of the transient chambers of each of the compressor and expander to be varied.
• the mixture is ignited.
• This causes a detonation of the air/fuel mixture and the consequent generation of a supersonic shock wave that propagates through the detonation chamber 4 and into the expander 6.
• the gases within the detonation chamber and expander expand causing rotation of the rotors of the expander.
• the rotary expander is connected to a drive shaft such that rotary power can be drawn from the device.
• the rotary device shown in Figure 1 comprises a detonation chamber 4 in a stator cylinder having axial ports (not shown in Figure 1) towards either end.
• the axial ports 20 and 32 can be seen in Figure 3 and in section in Figures 4A to 4H and 5A to 5H.
• One of the axial ports 20 enables communication between the recess of the recessed rotor of the compressor and the detonation chamber.
• the other of the axial ports 32 enables communication between the recess of the recessed rotor of the expander and the detonation chamber.
• both the compressor and the expander are formed by a respective recess 7 and 18 and lobe 5 and 16 rotor arranged for rotation about respective axes .
• the rotors of each of the compressor and expander are most preferably of the type described in WO-A- 91/05747, the entire contents of which are hereby incorporated by reference.
• lobed rotor 16 has radial lobes P and Q which are identical in shape and are shaped upon rotation to co-operate with recesses R, S and T within the recessed rotor 18. This serves to define a transient chamber of variable volume between an interacting lobe and recess. As will be explained below, the transient chamber serves to receive expanding gases and extract energy from them.
• a gaseous working fluid e.g. an air/fuel mixture is provided in the housing surrounding the rotor pair 5 and 7 of the compressor and fills the recesses within the compressor recessed rotor 7.
• the compression cycle commences when a lobe from the lobed rotor 5 enters one of the recesses of the recessed rotor 7 and entraps a charge of the air/fuel mixture within the transient chamber defined by the co-operating surfaces of a recess of the recessed rotor 7 and a lobe of the lobed rotor 5.
• the cycle of operation of the rotary device will be described in detail below.
• each recessed rotor 7 and 18 of both the compressor and expander have axially central bores 9 and 11.
• each recessed rotor 7 and 18 is provided with a passage (shown in Figures 4A to 4H and 5A to 5H) that links the recess or recesses within the rotor to the bore of the rotor.
• Each of the rotor bores 9 and 11 fits closely adjacent to the outer surface of the stator cylinder 3 within which is defined the detonation chamber 4. This enables each of the ports within the stator cylinder 3 to be in communication with the entrance of the short passages leading to the recess within each of the rotors and consequently to the transient chamber formed between a respective rotor pair, during an appropriate sector of arc of rotation.
• the stator cylinder 3 defining the detonation chamber 4 is supported at each end in the two outer walls 8 (other not shown) of the housing which provide close fitting support for the outer end faces of the compressor rotor pair 5 and 7 and for the outer end faces of the expander rotor pair 16 and 18, respectively. End walls are provided to close both ends of the stator cylinder 3 thereby defining the detonation chamber.
• the wall at the compressor end of the detonation chamber 4 provides the location for an igniter such as a spark plug (not shown) or any other suitable means for igniting the charge within the detonation chamber.
• Both the compressor and expander rotor pairs (5 and 7; 16 and 18) may be supplied with moveable containment walls (shown in section in Figures 4A to 4H and 5A to 5H) .
• the moveable containment walls are preferably slideable elements provided to enable variable throughput of a working fluid of the rotary device during its operation.
• the throughput of working fluid may be varied, for example, in accordance with varying load or in order to maintain constant power delivery with varying altitude in certain applications.
• a grid (described in detail below with reference to Figure S) is fitted in the short passage leading from the transient chamber of the compressor into the detonation charier.
• the grid is an example of a component suitable for generating micro-scale turbulence in the charge gas as it leaves the compressor transient chamber and enters the detonation chamber.
• the micro-scale turbulence whilst producing turbulent eddy structures of very small size in the gas stream, is nevertheless of a very high intensity and produces local mean gas velocities of a high order. This specific form of turbulence is a precursor to the detonation process, which follows shortly afterwards in the detonation chamber.
• the turbulence raises the local gas dynamic energy of the air/fuel mixture to a high level so as to produce a high level of potential reactivity which is required for effective detonation of the charge.
• the grid also affects the entire charge flow, which passes through the passage, thus resulting in good homogeneity of both turbulence and fuel distribution at the micro-level over the whole of the charge, prior to initiation of detonation.
• Figures 4A to 4H show rotor end profiles at stages through a cycle for a compressor section of the rotary device. It will be understood that the rotary device may operate without a compressor, i.e. the air/fuel mixture being provided directly to the detonation chamber at ambient pressure.
• Each one of Figures 4A to 4H shows a profile section through the lobed and recessed rotors and a moveable containment wall at a point close to a gas intake end of the rotary device.
• the containment wall is shaped to engage the first and second rotors to define between the containment wall and the first and second rotor3 the transient chamber, wherein the containment wall is moveable to enable the maximum possible volume of the transient chamber to be varied.
• the recessed rotor has a hollow centre which rotates about a close-fitting stator cylinder having a hollow interior defining the detonation chamber.
• the stator cylinder has a port 20 and each of the recesses of the compressor recessed rotor has a passage 22 for communication with the port 20 in the stator cylinder during a part of the cycle of rotation of the rotor about the stator cylinder.
• the hollow interior of the stator cylinder serves as a detonation chamber for the rotary device.
• a transient chamber is formed between a recess and lobe of the rotors of the expander.
• the transient chamber increases in volume during a cycle to enable expansion of detonated gases from the charge.
• the transient chamber receives an amount of compressed charge such that the transient chamber of the expander also functions as a chamber in which detonation occurs.
• Figures 5A to 5H show end profiles at stages through a cycle for an expander of the rotary device.
• a cycle of the expander begins when a lobe surface U and a recess surface W of a pair of engaging rotors pass the point of maximum penetration of the lobe, i.e. as the tip of the lobe passes the point of minimum radiu3 of the recess surface W.
• the leading edge of the recessed rotor passage 30 approaches an opening edge of the port 32 within the stator cylinder 16 to which a pressurised fluid supply has access.
• pressurised fluid passes into the recessed rotor passage 30 and into a newly forming transient volume between the lobe and recess.
• the port 32 is now fully open, providing maximum flow capacity for the pressurised fluid to pass through into the transient volume defined between lobe surface U and recess surface W.
• the pressure of the pressurised fluid acts on the surfaces U of the lobe and W of the recess, thus urging the rotors into further action in the direction of rotation. It is likely that the pressure of the fluid will not be substantial and will not of itself have a significant effect in driving the rotors of the expander.
• the drive access occurs when the air/fuel mixture contained within stator cylinder 18 and the transient volume in the expander is detonated.
• a trailing edge of the recessed rotor passage 30 approaches the closing edge of the port 32 which starts to shut off the supply of pressurised fluid to the chamber defined between the lobe and recess.
• the trailing edge of the recessed rotor passage 30 reaches the closing edge of the port 32, thus closing off the supply of pressurised fluid and isolating the fluid which has already passed into the transient volume.
• the air/fuel mixture will have detonated causing a shock wave that effectively transfers the entire charge into the expander and causes a rapid expansion of the charge gases that drives rotation of the expander rotors.
• a rarefaction wave is formed behind the shock wave. The rarefaction wave creates a depression which will tend to be filled by a subsequent charge of air/fuel mixture entering the detonation and expansion chambers .
• rotation of the rotors causes the transient volume to increase, thus allowing the trapped fluid to expand whilst maintaining some pressure on the surface of the lobe U and recess W and continuing to energise the rotation of the rotors and any shafts to which they may be connected.
• the transient volume reaches its maximum capacity and the fluid reaches ambient pressure. At this point the fluid ceases to exert any net pressure on the lobe U and recess W surfaces prior to its release to the housing surrounding the rotor pair.
• the fully expanded fluid is released from the transient volume and may be released to an exhaust system under the natural pumping action of the rotor pair within their housing.
• Figure 6 shows a schematic representation of the cross section through an example of a grid as used in the passage between the compressor and the detonation chamber.
• the grid may be formed of plural elements each having sharp edges. A3 gas flows through spaces between the elements at high velocity, the sharp edges induce substantial micro-scale turbulence of the gas. This is desirable in this context as it ensures that the charge of air/fuel mixture within the detonation chamber has a high level of potential reactivity, which is required for effective detonation of the charge.
• the grid comprises plural elements of triangular cross-section. As gas passes through spaces between the elements, the sharp edges on the detonation chamber side of the grid cause the gas flow in their close vicinity to be extremely turbulent, thereby ensuring a high level of potential reactivity of the air/fuel mixture.
• Compression begins when the tip of the compressor lobe and the leading edge of the compressor recess are in register with the outer respective edges of the compressor movable containment wall. This coincidence is indicated at zero position on the scale of the angular position of the lobed rotor in Figure 7.
• a transient compression chamber is formed which is reduced in volume as the compressor rotors continue to rotate.
• the charging port After 6 degrees of rotation, the charging port begins - 13 -
• the detonation shock wave passes through the entire charge residing in the detonation chamber and through the open discharge port to reach the fresh charge already residing in the expander transient chamber.
• a rarefaction wave is set up, as the charge remaining in the detonation chamber is expelled from the detonation chamber and into the expander transient chamber by the expansion effect of the detonation process.
• it has immediate effect in urging the further rotation of the expander rotor pair.
• the discharge port closes and the charge, being now effectively contained entirely within the expander transient chamber, expands, giving up its pressure energy which is converted into torque effect on the expander rotors.
• the expansion continues until the charge is released from the expander transient chamber as the tip of the expander lobed rotor and the leading edge of the expander recessed rotor clear the outer edges of the expander containment wall. At this point, the charge has reached approximately ambient pressure and all the pressure energy generated by the detonation is converted into shaft work.
• the charging port begins to open to admit fresh charge for the next cycle, compression of which has already begun.
• Conditions in the detonation chamber at this point are of substantial depression below ambient pressure due to the rarefaction wave established by the detonation process. This means that work being done by the compressor rotors in delivery of the fresh charge is neutralised by virtue of the existence of a negative pressure gradient between the compressor transient chamber and the detonation chamber.
• Additional ports may be disposed around the periphery of the stator cylinder 3, of similar axial length but reduced in width compared with the port 20 as illustrated. At this stage, these additional ports will be in alignment with the passages 22 in the remaining recesses of the recessed compressor rotor which are not currently in engagement with a lobe. The additional ports will thus allow fresh charge to briefly enter the detonation chamber 4 from the plenum surrounding the compressor rotors while the pressure gradient caused by the rarefaction wave in the detonation chamber 4 exists and before fresh charge is delivered into the detonation chamber 4 from the newly active transient chamber of the compressor rotors. This minimises the work input required for providing the engine with fresh charge and results in a highly efficient engine cycle whose operation results in minimal internal losses of the heat energy released from the fuel contained in the charge.
• Figure 8 shows schematically a section view of an example of a rotary device according to a further embodiment of the present invention.
• the rotary device of Figure 8 includes radially disposed ports on both the compressor and expander in addition to the axial ports connecting the detonation chamber with the compressor and expander rotor pairs.
• a ported disk is provided attached to the delivery end face of one or both of the recessed rotor of each of the rotor pairs.
• Each disk has one or more ports arranged therein and therefore each of the ports in the disks is located at the delivery end of the rotor recess.
• the rotary device includes a port 34 arranged on an end face of che compressor recess rotor 5.
• a transfer passage 36 is arranged to provide a route for gases to pass from the transient chamber of the compressor to the detonation chamber 4.
• an end face of the expander recess rotor is provided with a port 38 through which the transient chamber of the expander can receive gases from the detonation chamber 4.
• a transfer passage 40 is arranged to provide a route for gases from the detonation chamber 4 to the transient chamber of the expander via the port 38.
• gases may also be transferred to and from the detonation chamber via the transfer passages 36 and 40 between the respective end faces of the recess rotor 7 of the compressor and the recess rotor 18 of the expander.
• the passage 36 which connects the port 34 to the detonation chamber 4 includes turbulence generating means such as a grid, similar in form to that described above with reference to Figure 6.
• the grid serves to engage the charge gases just prior to entry to the detonation chamber as described above for the axial port arrangement .
• the ports in the disks of the respective compressor and expander recessed rotors communicate with ports in the corresponding end walls of the rotor housing supporting the compressor and expander rotor pairs. As the rotors rotate, a sliding engagement between the end walls of the housing and the disks arranged on the rotors provides control over the timing of the opening and closing of the ports in the disks.
• the disks are manufactured as separate components and thereafter are arranged on the end faces of the respective rotors.
• ports are also provided in appropriate end faces of the rotary device. This enables an increased flow of charge gases to be achieved within the rotary device. It will be appreciated that only axial ports or only radial ports may be provided. In one embodiment, one of the expander and compressor is provided with axial ports and the other with radial ports.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Rotary Pumps (AREA)

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• 2004
  • 2004-06-29 GB GB0414524A patent/GB0414524D0/en not_active Ceased
• 2005
  • 2005-06-27 WO PCT/GB2005/002503 patent/WO2006000797A1/en active Application Filing
  • 2005-06-27 EP EP05755207A patent/EP1766188A1/de not_active Withdrawn
  • 2005-06-27 JP JP2007518677A patent/JP4729041B2/ja active Active

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