The Study On Supercharging Characteristics And The Application In Refrigeration And Heat Pump Systems For Condensation Wave Rotor

The wave rotor is a device that utilizes pressure waves to directly exchange energy between high and low pressure fluids.,Based on the unsteady flow,the working efficiency of wave rotor is much higher than that of the ejector.And the wave rotor has the advantages of simple structure,excellent performance at aqueous operation,a small temperature rise in the supercharging process compared to the centrifugal compressors.At present,research on wave rotors is mainly focused on the field of gas turbines,pressure wave superchargers,and gas wave refrigeration by expanding.For the study of the application of wave rotors in water-based refrigeration systems or multi-effect evaporation（MEE）systems,there are few references abroad,and it is the first time in the country.This paper aims to solve the problem of vacuum steam compressor development and the low efficiency of the ejector.The theoretical and experimental studies on condensation wave rotors have been conducted.In this paper,we has finished the design procedure of the condensation wave rotor and analyzed the flow of the condensation wave rotor in detail.Based on the supercharging and self-cooling characteristics of the condensation wave rotor,the vapor compression refrigeration system with condensation wave rotor has been presented,and a detailed thermodynamic analysis of the system has been carried out.The feasibility study of the condensation wave rotor in MEE platform has been carried out.The main conclusions and related work are as follows:（1）The design of condensation wave rotor and the analysis of its internal flowBased on steam thermodynamic model,one-dimensional wave theory and VBA language,we complete the design program of condensation wave rotor,and we verify the program with computational fluid dynamics simulation.Through the numerical analysis of multi-channel 2D model,the operation rules of shock wave,expansion wave and contact surface are obtained.Through the numerical analysis of the single-channel model,it is found that the degree weakening of shock wave increase with the increase of the opening time of the channel.By reducing the width of the channel or increasing the rotating speed,the influence of the channel opening can be weakened.The distortion of the contact surface under vacuum conditions is very serious,resulting in the violent blending of high and low pressure fluid,which will reduce the performance of the wave rotor.（2）The thermodynamic analysis of the vapor compression refrigeration system with condensation wave rotorWe built thermodynamic models of three-port wave rotor and the refrigeration system,and the former is verified with HYSYS.By using the supercharging ability,the pre-boosting process of the wave rotor makes a reduction of pressure ratio of the compressor at the given condensation and evaporation pressures.By using the self-cooling ability,the pre-boosting process of the wave rotor can get a small temperature rise.The two characteristics decrease the difficulty of developing R718 compressor.For natural refrigerant R718 in WR-C cycle,the degree of superheating at the inlet of the compressor increases with the decrease of evaporation temperature.When condensation temperature T_c=35℃and evaporation temperature T_e=10℃,the degree of superheating at the inlet of the compressor is not more than 4.1℃,which shows the self-cooling capacity of condensation wave rotor.The improved system（WR-ARC）has a better performance of decreasing the pressure ratio of compressor,which is reduced by 20.6%⁶.5%compared to that of E-ARC system with R23/R134a at the Z1 range of 0.2 to 0.7,when the evaporation temperature T_e=-30℃,condensation temperature T_c=40℃,the condenser outlet vapor fraction x₄=0.45,condensing-evaporator outlet temperature of the hot stocks T₇=10℃,the outlet pressure of the high pressure throttle valve P₅=0.5 MPa.（3）The feasibility study of the condensation wave rotor in MEE platformThe influence of the initial expansion ratio of the condensation wave rotor on the performance of the equipment is investigated.At the driving steam of 100 kpa and frequency of 55 Hz,Angle ofα+4°has the highest average temperature rise,and the highest temperature rise is 23.5℃,which is very close to the temperature rise of 25-30℃for high-speed centrifugal steam compressor.The condensation wave rotor has obvious advantages over the small temperature rise of roots and ordinary centrifugal steam compressor and the high speed of high-speed centrifugal steam compressor.These prove the feasibility of the application of the condensation wave rotor in MEE system.