CO2跨临界双级压缩循环性能研究及理论分析

为了探索CO2跨临界双级循环系统性能提高的方法，基于热力学循环分析方法，对CO2跨临界双级压缩循环建立了数学模型，并进行了理论分析．结果表明：在分析的几种循环中，2个气体冷却器双级循环最优高压最高，带中间冷却器和膨胀机双级循环最优高压最低；低压缩机效率对整个循环性能的影响要比高压缩机效率更为显著；带中间冷却器的循环存在最佳质量分配比；随蒸发温度增加，带中间冷却器的循环要比2个气体冷却器的循环最优中间压力变化要小；气体冷却器出口温度对循环性能的影响，要比蒸发温度的影响大；相同条件下，2个气体冷却器带膨胀机双级循环和带中间冷却器和膨胀机双级循环性能最优，2个气体冷却器双级循环性能最差，膨胀机循环性能要普遍优于节流阀循环性能．

Performance Research and Theoretical Analysis of CO_2 Transcritical Two-Stage Compression Cycle

In order to explore the method of increasing system performance of CO2 transcritical two-stage compression cy- cle,mathematical models of CO2 transcritical two-stage compression cycle were built and theoretical analysis was made based on thermodynamic cycle analysis method. Results show that,among the several cycles,the optimal high pressure of TSCV＋TG cycle is the highest,while that of the TSCE＋IC cycle is the lowest,and the efficiency of low pressure stage compressor influences performance of the whole cycle more remarkably than that of high pressure stage compressor. Results also lead to the following conclusions. The two types of cycles ,TSCV＋IC and TSCE＋IC ,have the best quality distribution ratio. With the rising of evaporating temperature,the changes of optimal intermediate pressure in TSCE＋IC cycle is smaller than that of TSCV＋TG and TSCE＋TG cycle. Outlet temperature of gas cooler has more influences on cycle performance than evaporating temperature does. In the same conditions, the cycles of TSCE＋TG and TSCE＋IC have the optimum performance,and the cycle performance of TSCV＋TG is the worst,and the performance of expander cycle is superior to that of the throttling valve cycle.