CO_2跨临界循环中绝热毛细管性能试验研究

搭建了CO2跨临界循环毛细管性能试验台,通过控制变量法,分析了毛细管尺寸(管径、长度)和系统运行工况(入口压力、入口温度)等参数对毛细管质量流量的影响趋势和程度,而且发现:即使在非临界流的情况下,蒸发压力对质量流量的影响也很小。运用量纲分析法计算出了毛细管质量流量无量纲试验关联式:根据毛细管出口压力、入口温度、管径和长度可计算出毛细管CO2质量流量,并对该方程的可靠性进行了分析。结果表明:95%的预测值和试验值偏差维持在了±10%以内。

Experimental Investigations on Adiabatic Capillary Tube with CO2 Transcritical Cycle

A text facility of capillary tube that reproduces a transcritical refrigeration cycle was constructed. The impact degree and trend of both tube geometry( capillary diameter and tube length) and operation conditions( inlet pressures and inlet temperature) on the CO2 mass flow rate was evaluated by this facility with a strict control of the variables. The exit pressure had no significant effect on the refrigeration mass flow rate even in non-choked capillary tube flows. By performing the dimensional analysis,the non-dimensional correlation was carried out which we used to calculate the mass flow rate before inlet pressure,inlet temperature,tube diameter and tube length had been acquired. The reliability of the equation had been analyzed and the result indicated the mass flow rate predicted is in good agreement with the experimental mass flow rate as 95% of the capillary tube mass flow rate datum lie in an error band of ± 10%.