Gas compressors are widely used in process industries such as petroleum and chemical industries, as well as in commercial and civil applications. At present, the volumetric compressor of the commonly used volumetric compressor increases the temperature rise of the gas as the compression ratio increases. To prevent the oxidation and deterioration of the oil, the compression ratio of the single-stage compression is not excessively large. In order to achieve a higher press ratio, multi-stage compression and inter-stage cooling are usually employed. Compared with single-stage compression, multi-stage compression makes the refrigeration system complicated and troublesome to operate and maintain. Fluid-jet gear compressors are volumetric compressors, but their compressors are different from conventional positive displacement compressors. Currently, widely used volumetric compressors such as reciprocating and rod compressors have their compression chamber volume changed by mechanical movement of the relevant components, while the gear compressors inject a certain amount of fluid into the compression chamber (high pressure) Freezer oil or refrigerant vapor from the evaporator>, the fluid occupies a part of the volume of the compression chamber, so that the volume of the original gas in the compression chamber is correspondingly reduced to achieve compression. Since the temperature of the injected fluid is low, the compression can be effectively reduced. Temperature rise, therefore, this compressor is expected to achieve single-stage high compression ratio compression, if the development is successful, there will be broad application prospects. This paper mainly conducts thermodynamic analysis of its compression process. 1 The working principle of the gear compressor, as shown, the gas enters the suction chamber of the gear compressor via the pipeline, the tooth gap is closed by the body and the front and rear end caps, and the low-pressure gas charged from the suction chamber is enclosed in the teeth due to As the gear rotates, the gas in the suction chamber is continuously sent to the exhaust chamber. During the gas transfer process, high-pressure oil is continuously injected into the gums in a tangential direction to compress and cool the gas in the gums. After the injection compression, the gas pressure in the cogging rises to a predetermined pressure, the pressure difference between the inlet and outlet of the nozzle disappears, and the injection stops. Then, the high pressure tooth groove enters the exhaust chamber, and the oil therein enters the high pressure oil pool, and the compressed gas enters the exhaust chamber and is discharged through the upper exhaust pipe. After the exhaust is completed, a pair of gums mesh below the oil surface, and the oil filled in the gums is again discharged by the meshing teeth. When the tooth groove of the emptied oil enters the suction chamber, the inflation is restarted, and the cycle of the compressor is completed. The gear compression machine knot ft shows the compression process analysis in the B 3 tooth. In order to facilitate the thermal process analysis of the gear compressor cogging, it is assumed that the oil is evenly mixed with the gas in the tooth groove after the gum is injected into the tooth ridge. The process of sweeping through the nozzle exit is completed in an instant. If the compression process is adiabatic, the gas in the cogging is compressed by the nozzle and the gas temperature is: the gas volume in the gum is compressed by the nozzle and the volume of the gas becomes: for the variable process, only The mass of the oil that needs to be injected into the tooth gap by the variable index n instead of the nozzle is: body specific heat capacity, 4 is the specific heat capacity of the oil, Ty is the oil inlet temperature, and T' is the average temperature after the oil and gas is mixed. The average temperature after mixing of the oil and gas is: the above formula gives the temperature of the gas in the gum after adiabatic compression. The gingival compression process is inevitably accompanied by heat transfer. Therefore, the actual compression process is a multi-variable process. First, T (for the initial value, the multi-variable index lnPH/PtnT7T+lnPPH is obtained according to the equivalent end point method, and then the obtained n is replaced. The adiabatic index k in equations (1) and (2) is iteratively calculated until the given accuracy requirement is met, and the variable index is obtained. n. The oil injected into the tooth gap should be such that the gas in the gum is Compressed to the compressor discharge pressure PH, the volume of gas in the gum after compression is: the time that the tooth gap sweeps through the nozzle is: T = 缒 "One according to the Bernoulli equation: z is the tooth speed, P2 is the outlet pressure The 21 and the sentence are the height positions of the nozzle inlet and outlet in the system coordinate system, respectively. Since the difference between the inlet and outlet of the nozzle is a small amount compared with the kinetic energy difference and the pressure difference, it can be ignored. The speed at which the nozzle inlet oil is small is also negligible. Then, the Bernoulli equation is simplified as follows: the mass flow ft of the fuel injection is expressed as follows: assuming that the oil is injected for t time, the amount of oil injected reduces the volume of the gas in the tooth gap from V to V, then the gums are The pressure P of the internal gas is: Substituting the formula (13) into the formula (11), then the nozzle outlet oil velocity u is: assuming that after a T-time injection, a micro-injection time is elapsed, and the injection is performed. The oil volume in the cogging is 8V, and the mass of the oil injected into the tooth gap is: that is, at the same time, the mass of the oil ejected from the nozzle in 8t is: the oil ejected from the nozzle in the Si: time all enters In the tooth groove, after substituting the formula (14) into the upper formula, the two sides are integrated and arranged: the premise of the above derivation is that the speed of the outlet of the nozzle is reduced to zero during the time when one of the slots passes over the nozzle. Therefore, the derived formula is the minimum area formula for compressing the gas pressure in the cogging from the outlet to the PH nozzle. Reasonable determination of the nozzle outlet area of ​​the gear compressor is the key to designing and researching the gear compressor. If the nozzle n-area design is too small, the required exhaust pressure cannot be achieved. The sneeze exit area relationship given by equation (18> includes the rotational speed, gear structure parameters, physical properties of the working medium and state parameters. Therefore, it can be used to analyze the influence of the cable and the analysis of the variable operating conditions of the compressor. 4 Calculation results of the compression process and analysis of the bookmark5 gear compressor gears are two identical straight tooth involute shift teeth 1440r / min, compressor suction pressure P pressure PH = 1.0MPa, suction temperature T303K, oil inlet temperature Ty =308K. Calculate the knot as shown by ~. For the curve of the oil velocity at the nozzle outlet with time, it can be seen from the figure that the nozzle outlet oil velocity u is not a fixed value. At the instant of fuel injection, the u value is the largest. As the injection process progresses, the u value is gradually reduced. Small, at the end of the injection, u drops to zero. For the curve of gas volume in the tooth gap with time, it can be seen from the figure that as the injection process progresses, the volume of gas in the gum is continuously reduced to achieve compression. For the curve of the gas pressure in the tooth gap with time, it can be seen from the figure that as the injection process progresses, the gas pressure in the tooth gap continuously rises and finally reaches the discharge pressure of the compressor. For the gas compression process in the cogging, the figure shows that the gas compression process curve and the constant temperature process curve in the gums are basically coincident. The main reason is that the oil filled into the cogging is from the oil separation cooler, and the degree is low. The heat capacity of the oil is larger than the compressed gas in the tooth gap, so the average temperature of the oil and gas mixture after mixing is low. 5 Conclusion Through the above analysis of the gas compression process in the cogging of the gear compressor, it is shown that the fluid injection in the cogging of the gear can realize the compression of the gas in the cogging; the gas compression process is a variable near the constant temperature process. The compression ratio, corresponding to a minimum nozzle exit area, can be used to determine the minimum nozzle exit area and to perform variable operating conditions. Features Conveyor Equipments,Pneumatic Four Way,Conveying Equipment For Feed Plant,St3Q Series Pneumatic Four Way XinxiangHexie Feed Machienry Manufacturing Co.Ltd , https://www.feedmill.nl
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