CO_2跨临界循环中绝热毛细管数值模拟计算与分析

前期通过搭建试验台,分析了二氧化碳跨临界循环中毛细管的节流特性,并运用无量纲分析法计算出了毛细管质量流量无量纲试验关联式,经可靠性分析发现该关联式优于diogo的关联式。若超出考虑的范围时,该关联式模型可能产生较大的误差。由此,利用微元分割法,设计VB程序对毛细管长度和流量进行数值计算,将计算结果与前期试验测试结果和文献值做比较。在流量计算方面:95%的计算值与前期试验值的偏差在10%以内,与文献试验值的偏差全部在10%以内。在长度计算方面,90%的计算值与前期试验值的偏差在15%以内,75%的长度计算值与文献试验值的偏差在15%以内;在偏差分布方面:流量计算值与前期试验值和文献试验值,均有95%以上的流量计算值与试验值的偏差在10%以内。最后利用该计算程序,在标准工况下对毛细管尺寸进行数值计算,绘制成毛细管选型图。

Numerical Simulation and Analysis on Adiabatic Capillary Tube with CO_2 Transcritical Cycle

Preliminary,a test bench was set up to analyze the characteristics of the capillary in the process of carbon dioxide transcritical cycle,and calculate the dimensionless experimental correlation of capillary mass flow by using the method of dimensionless analysis. Its reliability analysis is better than the correlation of diogo. If the range is beyond the consideration,the correlation model may have a large error. So,we use the micro segmentation method to design VB program to calculate the length and the mass flow of the capillary tube and compared with previous experimental results and references result. In terms of flow calculation:the deviation between 95 % of the calculated results and the primary experimental results is less than 10 %;the deviation between the all calculated results and the references results is less than 10 %. In the calculation of the length:the deviation between 90 %of the calculated results and the primary experimental results is less than 15 %;the deviation between 75 % of calculated results and the references results is less than 15 %. In terms of deviation: more than 95 % of mass flow calculation value the compared with the primary experimental results and the references results,the deviation is less than 10 % has mo in terms of mass flow. Finally,we use the calculation program the calculation calculate the size of the capillary in one condition and draw a chart for some capillaries type selection.