RU2133000C1 - Method and device for conversion of heat - Google Patents

Abstract

FIELD: thermal engines, thermal transformers and thermal pumps; drying and evaporating devices. SUBSTANCE: method consists in simultaneous compression and expansion of different portions of gaseous working medium at balanced heat exchange between them through contact of working medium of both processes with one and the same regenerative surfaces followed by restoration of pressure to initial level in adiabatic processes. Used as working medium in one of cycle is mixture of gases and steam which is transformed into liquid phase in the course of compression. Liquid phase is removed from cycle. Restoration of pressure of remaining mixture is effected at constant temperature. EFFECT: enhanced efficiency of drying and evaporating. 4 cl, 6 dwg 2

Description

 The invention relates to heat engineering and can be used in heat transformers, energy-efficient devices for drying and evaporation, for example, food products and also as low-temperature heat engines.

 From the technical literature there are a large number of methods for converting heat (thermodynamic cycles) with a working fluid both in the form of a pair of low-boiling liquid and gas, such as air. Closest to the proposed method is the method according to Russian patent 2062413, which consists in the fact that the heat is converted by two simultaneous processes of compression and expansion of different portions of gas with balanced heat transfer between them by contacting the working fluid of both processes with the same regenerative surfaces, followed by restoration of pressure to initial pressure under adiabatic conditions. This method of heat transformation, by its nature being a splitting one, has unique technical characteristics. For example, with an increase in the asymmetry of the cycles, its efficiency exceeds the similar indicators (at the same temperature ratios) of the Carnot cycle by about two times. The high efficiency of the splitting cycle according to patent 2062413 make it promising in other areas of use of heat transformers, for example, in drying and evaporation processes.

 From the literature there are known methods of using heat pumps for these purposes, for example, see the book: E.I. Yantovsky; L.A. Levin. "Industrial heat pumps." Moscow. Energy Publishing House 1989 p. 45-65. In the examples discussed in the book, the heat pump is used as a means of utilizing waste heat through a large number of heat exchangers, which is justified in large-scale production and completely unsuitable for domestic use.

 The present invention solves the problem of creating a compact, energy-efficient device for drying and evaporation in domestic conditions or conditions of mobile devices, for example, when drying berries, fruits, juices, grains or green grass mass.

 This problem is solved by the fact that in the splitting heat pump according to patent N 2062413, the working fluid of one of the cycles directly uses a mixture of air with water vapor after they pass the evaporated or dried product, and the water vapor in the compression process goes into the liquid phase, which is removed from circulation, and the rest of the mixture is restored pressure, or used sequentially in the second, thermally balancing first, cycle at a constant temperature.

 A device that performs isothermal processes by this method can be a two-rotor machine with a cylindrical body, inside of which two rotors with a developed regenerative surface inside the working chambers are concentrically arranged to it one another.

 The disadvantage of this device is that the regenerative plates are movable (relative to the blades) in the circumferential direction, which is difficult to perform with a high degree of reliability at high rotor speeds. A more perfect regenerator device is proposed in the description of the USSR author's certificate N 1377459, where the heat transfer plates are made wavy and interconnected by radial seams passing along the wave crests, the packages have force plates having a wedge cross-section with a tip to the axis of rotation, and the packages are attached to the rotor blades by means of bellows.

 The main disadvantage of this device is the radial instability of this "spring" in the field of centrifugal forces. During rotation, the package is forced to slide on the surface of the cylinder, clinging to it with a force proportional to the square of the speed, which will inevitably lead to the destruction of both.

 The present invention solves the problem of ensuring the absolute reliability of the regenerator.

 The problem is solved in that the regenerative plates are located perpendicular to the axis of rotation of the rotors directly on the blades so that at the moment of closing of the working chambers, the plates of one counter-blade occupy the gaps between the plates of the other.

 The prototype patent does not indicate the type of drive for the uneven rotation of the rotors. From the technical literature there are many mechanisms of uneven rotation. These are lever-link and crank mechanisms, the main disadvantage of which is the presence of unbalanced masses and the difficulty of obtaining optimal parameters of uneven rotation.

 Closest to the proposed transmission is the transmission of gear elliptical wheels, described, for example, in the book of S. N. Kozhevnikov and others. "Mechanisms". Moscow. , Mechanical Engineering, 1976, pp. 156 - 159. The transmission with these wheels can be fully balanced and reliable in operation, but the nature of uneven rotation is also not optimal for the dynamics of a two-rotor machine.

 The present invention solves the problem of creating a transmission completely subordinate to the optimal dynamics of a two-rotor machine.

 This problem is solved by the fact that the radii of the dividing lines of the gear set from the condition that the uneven movement of the driven link is the sum of two simple movements: portable, uniform rotation and relative, harmonic vibrational with an amplitude determined by the number of blades on the rotors.

The proposed method is illustrated in FIG. 1; FIG. 5 and FIG. 6. In FIG. 1 shows a P - Y diagram of air with a grid of isotherms T ₁ ; T ₂ ; T ₃ and thermodynamic cycles according to the proposed method.

 In FIG. 5 shows a schematic diagram of a device for drying and evaporation with a mechanical drive.

 In FIG. 6 is a schematic diagram of a heat driven drying apparatus. A device for carrying out isothermal processes according to the method is illustrated in FIG. 2; FIG. 3 and FIG. 4.

 In FIG. 2 shows a cross section of a two-rotor machine, and FIG. 3 its circumferential section A - A.

 In FIG. 4 shows a pair of gears of the proposed drive.

 A device for the implementation of the isothermal parts of the cycles of the proposed method (see Fig. 2 and Fig. 3) consists of a cylindrical body 1 with inlet 2 and 5 and outlet 4 and 5 windows. Inside the cylinder there are two rotors with blades 6 on one and 7 on the other. Each blade is made with radiators from heat transfer plates 8. The device is shown at the moment when both rotors have the same speed, but one accelerates and the other slows down.

 The drive of the uneven rotation of the rotors consists of a pinion gear 9 with a flywheel 10 and a driven wheel 11 with two sprockets 12 engaged with a groove 13, which is a hodograph of the sprocket on the flywheel 10.

 The device for drying food products with a mechanical drive (see Fig. 5) consists of two two-rotor machines 14 and 15 with a common drive of uneven rotation (not shown), Machine 14 with heterogeneous working chambers, and machine 15 with homogeneous ones. The lower windows of the machine 14 are interconnected and a tank 16 for collecting condensate. The hopper 17 for accommodating the drained product is connected to the machines and the atmosphere with air ducts.

 The device for drying products with a thermal drive (see Fig. 6) also consists of two two-rotor machines with a common drive. Both machines are three-sectional (each rotor has 5 blades). Machine 18 with heterogeneous working chambers, and machine 19 with homogeneous ones. In the lower part of the machine 18, the exhaust of the compressor part is connected to the inlet of the expander and the condensate collecting tank 20. The product to be dried is placed in a hopper 21 connected to the machines with an air duct. The source of the movement of machines and heat for drying the product is a heat exchanger 22, fed by the flame of the burner 23.

Второй ротор вращается от ведомой шестерни 9, смещенной относительно первой на угол 180 градусов со скоростью:

Таким образом, момент количества движения системы роторов:
∑M₁ = ω₁J₁+ω₂J₂ = J₀ω₀ = const;
(при равенстве моментов инерции роторов J₁=J₂=J₀). В момент, когда оба ротора имеют одинаковую скорость (фиг. 2), наружные поверхности лопастей 6 и 7 перекрывают впускные и выпускные окна, но уже в следующий момент лопасть 6 начинает открывать впускное окно 2 для всасывания в левую часть устройства, подключенную как компрессор. В правой части, подключенной как детандер, открывается окно 3 для впуска сжатого газа и окно 4 для выпуска отработанного в детандере газа. Лопасти 6 в этот отрезок времени движутся с ускорением, а лопасти 8 замедляются, поэтому рабочие камеры компрессорной части сокращают свой объем, происходит сжатие, пока замедляющаяся нижняя лопасть 7 не откроет окно выхлопа компрессора 5, после чего начнется процесс выталкивания сжатого газа из рабочей камеры компрессора. Поступление сжатого газа в детандерную, левую часть прекратится, когда окно 3 перекроет нижняя лопасть 7. В рабочей камере детандера с этого момента заканчивается процесс заполнения и начинается процесс расширения, который продолжается до момента, пока лопасти 6 и 7 не поменяются местами в момент равенства скоростей. С этого момента все процессы повторятся, но уже с другими порциями газа.The device operates as follows:
The pinion gear 9, rotating uniformly, rotates the driven wheel 11, and with it one of the rotors with an angular speed:

The second rotor rotates from the driven gear 9, offset relative to the first by an angle of 180 degrees at a speed:

Thus, the angular momentum of the rotor system:
∑ M ₁ = ω ₁ J ₁ + ω ₂ J ₂ = J ₀ ω ₀ = const;
(with equal moments of inertia of the rotors J ₁ = J ₂ = J ₀ ). At the moment when both rotors have the same speed (Fig. 2), the outer surfaces of the blades 6 and 7 overlap the inlet and outlet windows, but already at the next moment, the blade 6 begins to open the inlet window 2 for suction in the left part of the device, connected as a compressor. On the right side, connected as an expander, a window 3 opens for the inlet of compressed gas and a window 4 for the release of gas exhausted in the expander. The blades 6 in this period of time move with acceleration, and the blades 8 slow down, so the working chambers of the compressor part reduce their volume, compression occurs until the slowing down lower blade 7 opens the exhaust window of the compressor 5, after which the process of pushing the compressed gas from the working chamber of the compressor begins . The flow of compressed gas into the expander, the left part will stop when the window 3 closes the lower blade 7. In this working chamber of the expander, the filling process ends and the expansion process begins, which continues until the blades 6 and 7 exchange places at the same speed . From this moment, all processes will be repeated, but with other portions of gas.

 The described type of machines in comparison with other three-dimensional machines has a unique property: inside the working chambers there is a vortex movement, blowing around the walls of the chambers and the more powerful, the greater the speed. The direction of the vortex is shown in FIG. 2 arrow. The root cause of the vortex is the rotation of rotors with different speeds so that inside the working chambers opposite wall-blades periodically have different angular velocities, just like the adjacent gas layers, the difference in the centrifugal forces arising in them, and causes the vortex movement of the entire volume gas. A strong vortex movement makes the gas superconducting, as it were, and only an insufficient increase in gas heat transfer - the wall forces to resort to fins of the blade surfaces with plates 8. The strong influence of the wall on the thermodynamic process inside the chamber gives grounds to call these chambers heterogeneous. In machines 15 and 19 (Fig. 5 and 6), the same in design, but intended for adiabatic processes, instead of finning the blades, they are insulated. Such chambers are called homogeneous.

The method used for drying or evaporating the product is as follows. The heated air passing through the product in the chambers 17 (Fig. 5) is saturated with moisture to 100% humidity, while lowering the temperature from T ₂ to T ₁ . Isobaric process 4 - 1 (see Fig. 1). This mixture enters the compressor part of machine 14, where it is compressed from pressure P ₁ to pressure P ₂ at a constant temperature T ₁ (process 1 - 2 of Fig. 1). Due to the fact that the partial pressure of the vapor in the saturated mixture depends only on temperature, the compression of the saturated mixture at a constant temperature leads to the fact that excess moisture falls into the liquid phase on the plates 8 (see Fig. 2 and 3) and is discharged by centrifugal forces to the walls cylinder and is carried away by the air flow through the window 5 into the vessel 16 (Fig. 5). The heat of vapor condensation and air compression is absorbed by the plates 8, the remaining part of the mixture with pressure P ₂ enters the inlet of the expander part through window 3 (Fig. 2), where it expands from pressure P ₂ to P ₃ , absorbing all the heat acquired from the plates 8 process 1 - 2, and doing external work. The expander exhaust enters the compressor part of the machine 15 (see Fig. 5) with homogeneous working chambers, where it is compressed to a pressure P ₀ , raising the temperature to T ₂ (adiabat 3-4). The second part of the machine 15 is connected as a fan of the drying hopper 17. The hot exhaust of the adiabatic compressor is mixed with the air flowing through it through the product to be dried, which compensates for heat loss during evaporation of moisture in the product to be dried. The operation of the compressors and the fan is only partially compensated by the operation of the expander part (process 2-3 of Fig. 1). The rest is made up by a mechanical drive, such as an electric motor or internal combustion engine.

The operation of the device for drying and evaporation with a thermal drive (Fig. 6) differs from the device with a mechanical drive in that additional, third working chambers are used for thermal compensation of the main cycle, and air from the environment is used with a working fluid here. The work is as follows. Air with 100% humidity from the hopper 21 enters the compressor part of the heterogeneous machine 18, where it is compressed to a pressure P ₂ (isotherm 1 - 2, Fig. 1) with condensation of part of the moisture and its discharge in the lower part with the exhaust into the reservoir 20. Exhaust the compressor part enters the first expander, where the pressure of the remaining part is reduced to P ₀ . The exhaust of this expander is heated in the heat exchanger 22 to a temperature T ₂ , mixed with the ventilation air of the closed chamber of the hopper. The heating is carried out from the flame of the burner 23. In parallel with this cycle, a second is carried out, in which the air from the environment is compressed in additional working chambers of the homogeneous machine 19 to a pressure P ' ₂ and by raising the temperature to the temperature of the drying chamber T ₁ (process 2-3, FIG. 1), after which it enters the second expander of a heterogeneous machine, where it is expanded to a pressure P ' ₃ using all the heat of condensation of moisture and performing external work. The exhaust of this expander enters the main compressor of the homogeneous machine 19, where it raises the pressure to P ₀ and the temperature (3 - 4, Fig. 1). The exhaust of this compressor is sent to the part of the hopper 21 for open drying.

может принимать сколь угодно большие значения в зависимости от ΔT = T₂-T₁, (см. фиг. 1)
так как

Но с уменьшением ΔT уменьшается интенсивность процесса сушки. Компромиссное значение ΔT и ξ выбирают в зависимости от места применения. Так для сушки в бытовых условиям ξ оправдано в пределах 10 - 15, для подвижных устройств в пределах 15 - 20, а для крупных стационарных устройств свыше 20.The energy conversion efficiency in a device with a mechanical drive (Fig. 5) is expressed as follows:

can take arbitrarily large values depending on ΔT = T ₂ -T ₁ , (see Fig. 1)
as

But with a decrease in ΔT, the intensity of the drying process decreases. A compromise value ΔT and ξ is chosen depending on the place of application. So for drying in domestic conditions ξ is justified within 10-15, for mobile devices within 15-20, and for large stationary devices over 20.

 The maximum fuel efficiency can be achieved in a device with a combined drive: mechanical from an internal combustion engine and thermal from an exhaust of the same engine. Efficiency in this case can be in the range of 5-10 depending on the application.

Claims (4)

 1. The method of heat conversion by means of simultaneous processes of compression and expansion of different portions of a gaseous working fluid with balanced heat exchange between them by contacting the working fluid of both processes with the same regenerative surfaces with subsequent restoration of pressure to the initial pressure in adiabatic processes, characterized in that as the working fluid in one of the cycles using a mixture of gases and steam, capable of in the compression process go into the liquid phase, which is removed from circulation, and in pressure stabilization of the remaining part of the mixture is carried out at a constant temperature.  2. The method according to claim 1, characterized in that a portion of the working fluid, consisting of gas and steam, is used sequentially and in the second, thermally balanced first, cycle.  3. A device for implementing the methods according to claims 1 and 2, comprising a cylindrical body with two rotors coaxial to each other and concentrically located to each other, with several equally spaced blades, together forming a circular chain of chambers with bodies located in them with a developed regenerative surface, and non-uniform rotation of the rotors, characterized in that the regenerative surfaces are formed by plates located perpendicular to the axis of rotation of the rotors directly on the blades so that Currently clamping plates of one of the working chambers kontrlopasti occupy the spaces between the other plates. 4. The device according to claim 3, characterized in that the non-uniform rotation of the rotors is carried out by non-circular wheels, the contact surfaces or dividing radii of which are formed according to the equations

r = A - R;

where R is the radius vector of the generator pinion;
A = const is the center-to-center distance;
K - coefficient of increase in portable speed 1.1 <K <2;
φ _o - the angle of rotation of the pinion gear;
n is the number of blades on the rotor;
r is the radius vector of the generating wheel;
φ _r is the angle of rotation of the driven wheel,
moreover, in the areas forming

gear engagement, and on the rest of the engagement is carried out by contacting the smooth surfaces of the wheels on one side and the sprockets on the driven wheel with the groove surface on the drive wheel, which is the hodograph of the sprocket on the wheel when moving according to a given condition.

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