本研究目的在於預測高速冷媒壓縮機更換冷媒前後之性能變化。採計算流體力學模擬的方法,比較工作流體自R-134a冷媒汰換為混合冷媒R-513A與氫氟烯烴冷媒(Hydrofluoroolefins, HFO)R-1234yf,對不同負載之性能及內部流場之影響。本文採用一單級280RT磁浮離心式冷媒壓縮機作為研究對象,使用NIST(National Institute of Standards and Technology)資料庫內之冷媒物性,搭配不同部份負載下之壓縮機轉速及質量流率,藉由模擬預測壓縮機替換冷媒前後的性能變化差異。壓縮機運轉條件為基於同一冷凍循環之冷凝溫度與蒸發溫度,以相同製冷能力為目標,比較使用不同冷媒之性能差異。本研究使用計算流體力學軟體(Computational Fluid Dynamics, CFD)進行流場模擬,結果顯示離心式冷媒壓縮機在直接更換冷媒後,相較於R-134a,R-1234yf葉輪滿載效率下降13.21%,R-513A滿載效率下降9.97%,而三種冷媒之部份負載效率差異較全載效率之差異小。
This study uses Computational Fluid Dynamics (CFD) to simulate and analyze the working fluid of the magnetic levitation centrifugal refrigerant compressor from R-134a to mixed refrigerant: R-513A and HFO (Hydrofluoroolefins) Hydrofluoroolefin refrigerant: R-1234yf , The impact on integrated part load performance IPLV (Integrated Part Load Value) and internal flow field. This study uses a single-stage 280 USRT maglev centrifugal refrigerant compressor as a simulation model, and uses three different refrigerants: R-134a, R-513A and R-1234yf in the NIST (National Institute of Standards and Technology) real gas database. The refrigerant is used to set the IPLV working conditions and change the compressor speed and mass flow rate to simulate the characteristic curve of the compressor after replacing the refrigerant. The compressor working conditions are the condensation and evaporation conditions of the fixed refrigeration cycle, and are in accordance with the same capacity standards. To compare the performance differences of different refrigerants, this study uses the CFD software in Ansys to simulate the flow field, and the turbulence uses the k-omega model. The results show that after the direct replacement of the refrigerant by the maglev centrifugal refrigerant compressor, based on R-134a, the full load efficiency of R-1234yf drops by 13.21%, the full load efficiency of R-513A drops by 9.97%, and the partial load efficiency is similar.