CN1079045A - Double circulation air expanding machine - Google Patents

Abstract

Double circulation air expanding machine belongs to refrigeration technology field.This machine has overcome on the present aircraft the wider bootstrap system air pressure height of employing increases heat transfer temperature difference; Be difficult for sealing, be difficult to make lubricant with working medium itself; Expansion ratio is big, the low shortcomings of the refrigerating efficiency that item determined such as the little and unnecessary refrigeration degree of depth of flow.Its principal character is an additional secondary circulation on a complete gas refrigeration circulates, hyperbar is near source air pressure in the system, major and minor circulation gas circuit is the section of overlapping at eddy flow expanding chamber and turbine turbine, be fit to the optimum condition characteristics that the turbine expansion ratio is little, flow is big, and the lubricating bearings of available working medium own.

Description

Double circulation air expanding machine

Double circulation air expanding machine belongs to refrigeration technology field.Can be used for freezing, refrigeration, air-conditioning, the empty branch.Especially have automobile, the train of compressed gas source, the cooling in summer of aircraft.

The existing in the past multiple gases decompressor of the present invention.As there is not a circulation of gas refrigerations such as back-heating type, level pressure back-heating type, constant volume backheat (Stirling) formula, all formulas of Sol, Ji Fute-McMahon formula, eddy current tubular type, wherein bootstrap system (a kind of improved aircraft airconditioning system) is close with the present invention, is adopting extensivelyr on the aircraft at present.But hyperbar more than 6 times of source air pressure (seeing below attached formula 1) normally in this system at first, heat exchanger thicken and cost are increased and heat transfer temperature difference is increased, thereby efficient reduces; Simultaneously, unfavorable to sealing, particularly little, the minicomputer that rotating speed is high is difficult can be with the lubricating bearings of working medium own, and efficiently little, minicomputer can not be realized; It three is that expansion ratio increases, and departs from the optimum condition characteristics that the turbo-expander flow is big, expansion ratio is little more, and the increment of turbine entropy is big; It four is to have the unnecessary refrigeration degree of depth, and is little than coefficient of refrigerating performance of the present invention at required temperature range.

Task of the present invention provides that hyperbar equals source air pressure in a kind of circulation overall process, and expansion ratio is little, and flow is big, be convenient to microminiaturization, the thermodynamic perfect degree height is big at required temperature range coefficient of refrigerating performance, non-environmental-pollution, compact conformation, the major and minor double circulation air expanding machine of the shunting that cost is low.

For realizing above-mentioned task, technical solution of the present invention is: double circulation air expanding machine is mainly by high-pressure ejector [1], spout [2], eddy flow expanding chamber [3], turbine [4], secondary turbine [5], diffluence room [6], power transmission shaft [7], gas bearing [8], discharging diffuser [9], low-pressure injection device [10], heat dump [11], diffuser [12], booster [13], force feed (braking) impeller [14], radiator [15], permanent-magnet stator [16], p-m rotor [17], turbine flexible pad [18], force feed impeller flexible pad [19], air deflector [20], lagging casing [21], spilling water device [22] etc. zero, parts are formed.Be characterized in an additional secondary circulation on complete gas compression, heat release, expansion, a heat absorption circulates.Major and minor circulation is carried out simultaneously.Hyperbar is near source air pressure in the system, and secondary circular flow is the several times of major cycle flow.The gas circuit of secondary circulation is: diffluence room [6], heat dump [11], diffuser [12], booster [13], radiator [15], high-pressure ejector [1], eddy flow expanding chamber [3], turbine [4], diffluence room [6].Major and minor circulating current path is the section of overlapping at eddy flow expanding chamber [3] and turbine [4], is just accord with the optimum condition characteristics that the turbo-expander expansion ratio is little, through-current capacity is big.The flow-control cross section of secondary circulation is located in the high-pressure ejector [1] parallel with the end face of Laval spout [2], and axis is along the tangential direction of eddy flow expanding chamber [3].Connect the outer circumferential of diffluence room [6] under the heat dump [11], upward be connected to booster [13] inlet by diffuser [12].Radiator [15] is connected between the side entrance of booster [13] outlet and injector [1].The perisporium of diffluence room [6] is little expansion surface of revolution, and diapire center evagination is so that air-flow viscous loss minimum wherein.

Second characteristics are that working medium is imported into the lubricated task that gas bearing [8] is finished rotatable parts after the expansion process of major cycle, are beneficial to little, the miniaturization of efficient decompressor.

The 3rd characteristics are that the wheel disc back side of (radially, axially) oblique flow reaction type turbine [4] and centrifugal backward type force feed (braking) impeller [14] is equipped with forward direction type centrifugal seal blade, to stop the blending of ganging up of high and low pressure air-flow.

The 4th characteristics are with flexible pad [19], [18] assembling, so that its self-centering between impeller [14] and turbine [4] and the axle [7].

The 5th characteristics are permanent-magnet stators [16] and are installed in the p-m rotor [17] of axle on [7] whole rotatable parts are floated, to subdue its resistance of start.

The 6th characteristics are axle [7] hollow, have both alleviated weight, have strengthened rigidity (seeing below attached formula 2) again, are again the air feed paths of gas bearing [8] simultaneously.

After this machine enters duty, Compressed Gas (as air) flows into spout [2] through valve, filtering, dehumidifying device, ejection back step-down at a high speed, cooling, and injection together tangentially sprays into eddy flow expanding chamber [3] rotation at a high speed from the gas of radiator [15], and then promote maglev major and minor turbine [4], [5] by axle [7] drive supercharging (braking) impeller [14] rotation at a high speed, to secondary gas flow pressurization from heat dump [11].What further step-down was lowered the temperature in the eddy flow expanding chamber [3] closes air-flow after major and minor turbine [4], [5] enter diffluence room [6], leaves very little remaining rotating speed.Higher speed away from the axle center, higher pressure, the higher temperatures air-flow is further that fast (paraxial gas radially heart motion increases angle speed, because of viscous effect with momentum, kinetic energy is along the footpath unofficial biography), enter heat dump [11] heat absorption back again to diffuser [12] reduction of speed supercharging, reenter booster [13] after impeller [14] pressurization (externally heat release simultaneously), go into radiator [15] cooling (heat can be taken away by ram-air in radiator [15] outside), this air-flow has become the normal temperature air-flow of stagnation pressure near source air pressure under the steady-working state, reenters high-pressure ejector [1] and goes into eddy flow expanding chamber [3] together with a source gas.Form secondary circulation.Near the axle center than low speed, lower temperature, than then further stall (momentum, kinetic energy are along the footpath unofficial biography) of low-pressure air current, centre bore through hollow shaft [7] flows to thrust gas bearing [8], after finishing lubricated task and entering the supercharging of discharging diffuser [9], tangentially flow out to low-pressure injection device [10], flow type pump with injection between shell [21] and air deflector [20] and the gas of the outside cooling of heat dump [11] together discharge, supply with refrigeration, idle call.Especially when being working medium with the air (working medium is desirable everywhere, does not have any pollution) can directly be delivered to and be transferred the space, and can be at the outside cool-down dehumidification of heat dump [11] by the air of low-pressure injection device [10] injection, and condensate water is discharged by spilling water device [22].

Accompanying drawing is small capacity double circulating air decompressor (valve matching used with it is the voltage-controlled dibit two-way valve of the electricity-saving type) schematic diagram that is used for truck cap cooling and small refrigerator cooling thereof.Below in conjunction with accompanying drawing embodiments of the invention are explained.

Eddy flow expanding chamber [3], diffluence room [6], discharging diffuser [9], air deflector [20], shell [21] is all made with fiberglass, turbine [4], force feed (braking) impeller [14], injector [1], spout [2], secondary turbine [5], hollow rigid power transmission shaft [7], gas bearing [8] is all made with corrosion-proof wear-resistant material, be loaded on the heat dump [11] between air deflector [20] and the discharging diffuser [9] and be loaded on the outer radiator [15] of shell [21], diffuser [12], booster [13] loam cake all plates non-corrosive metal (NCM) outward with copper and makes, permanent-magnet stator [16] and be installed in the axle [7] middle and upper part p-m rotor [17] make with permanent-magnet steel, flexible pad [18] [19] is all made with high-quality rubber.When source temperature degree is 313K(40 ℃), when absolute pressure is 0.9MPa, can with mass flow 193K(-80 ℃ in consumption gas etc.) primary air and 198K(-75 ℃ of 3 times of consumption makings amount flow) secondary streams.

Attached: the supercharging estimation formula of formula 1(bootstrap system)

$P_1\mathrm{=P}{}_O\mathrm{［1+}\sqrt{\mathrm{1-(P}{}_2\mathrm{/P}{}_O){}^{\frac{\mathrm{\gamma -1}}{\gamma }}}{］}^{\frac{\gamma }{\mathrm{\gamma -1}}}$

Wherein γ is adiabatic exponent (heat capacity ratio); P ₀Be source air pressure; P ₁Press (supercharger outlet pressure) for increasing the back; P ₂Be back pressure.

The isometrical hollow shaft critical speed estimation of formula 2(formula)

${\omega }_R=\frac{{\pi }^2}{{\mathrm{2L}}^2}\sqrt{\mathrm{E(R}{}^2\mathrm{+r}{}^2\mathrm{)/\rho }}$

ω wherein _RBe first critical speed; L is an axial length; E is an elasticity modulus of materials; ρ is a density of material; R is the axle external diameter; R is the axle internal diameter.

Claims (6)

1, double circulation air expanding machine.By high-pressure ejector [1], spout [2], eddy flow expanding chamber [3], turbine [4], secondary turbine [5], diffluence room [6], power transmission shaft [7], gas bearing [8], discharging diffuser [9], low-pressure injection device [10], heat dump [11], diffuser [12], booster [13], force feed (braking) impeller [14], radiator [15], permanent-magnet stator [16], p-m rotor [17], turbine flexible pad [18], force feed impeller flexible pad [19], air deflector [20], lagging casing [21], spilling water device parts such as [22] is formed.It is characterized in that an additional secondary circulation on complete gas compression, heat release, expansion, a heat absorption circulates.Major and minor circulation is carried out simultaneously, and hyperbar is near source air pressure in the system.The air flow path of secondary circulation is: diffluence room [6], heat dump [11], diffuser [12], booster [13], radiator [15], high-pressure ejector [1], eddy flow expanding chamber [3], turbine [4], diffluence room [6].The flow-control cross section of secondary circulation is located in the high-pressure ejector [1] parallel with the end face of Laval spout [2], and axis is along the tangential direction of eddy flow expanding chamber [3].Connect the outer circumferential of diffluence room [6] under the heat dump [11], upward be connected to booster [13] inlet by diffuser [12].Radiator [15] is connected between the outlet and high-pressure ejector [1] side entrance of booster [13].Diffluence room [6] perisporium is little expansion surface of revolution, and diapire center evagination is so that air-flow viscous loss minimum wherein.

2,, it is characterized in that working medium enters gas bearing [8] lubrication of superhigh speed power transmission shaft [7] simultaneously after the expansion process of major cycle according to claim 1 described " double circulation air expanding machine ".Be beneficial to little, the miniaturization of machine.

3,, it is characterized in that the wheel disc back side of (radially, axially) Oblique-flow turbine [4] and centrifugal backward type force feed (braking) impeller [14] is equipped with the forward direction type sealing blade that stops the mutual blending of high and low pressure air-flow according to claim 1 described " double circulation air expanding machine ".

4,, it is characterized in that between impeller [14] and turbine [4] and the axle [7] all with flexible pad [19], [18] assembling, so that its self-centering according to claim 1 described " double circulation air expanding machine ".

5,, it is characterized in that permanent-magnet stator [16] and be installed in the p-m rotor [17] of axle on [7] whole rotatable parts are floated to subdue its resistance of start according to claim 1 described " double circulation air expanding machine ".

6, according to claim 1 described " double circulation air expanding machine ", it is characterized in that power transmission shaft [7] hollow, both alleviated weight, strengthened rigidity again, be again the air feed path of gas bearing [8] simultaneously.