单螺杆膨胀机散热损失的实验研究

Experimental Study on Heat Loss of Single Screw Expander

单螺杆膨胀机作为有机朗肯循环系统中最适合的膨胀机类型之一,其性能对循环系统有重要影响。本文实验研究了有机朗肯循环系统中单螺杆膨胀机机壳及润滑油的散热损失及其在不同工况下对膨胀机性能的影响。实验结果表明,当进气温度由80℃升至123℃时,单螺杆膨胀机的散热损失增大,其中润滑油散热损失为主要散热损失,其散热量从0.5 kW增至1.05 kW。随着膨胀比的增加,各散热损失占比逐渐减小。其中,当进气温度由80℃升至123℃时,机壳散热损失占比为5.1%~2.5%,润滑油散热损失占比为16.1%~9.5%。说明随着进气温度的增加,膨胀机性能逐渐改善,工质气体通过散热损失的能量比例逐渐减小,散热损失对膨胀机性能的影响逐渐减小。

The performance of a single screw expander,which is among the most suitable types of expander in the organic Rankine system,plays an important role in the cycle system.One of the essential factors influencing a single screw expander performance is heat loss.This study experimentally investigated the heat losses of shell and lubricating oil based on the different inlet parameters of the single screw expander.Results demonstrated that the heat loss in the single screw expander would increase with higher inlet temperature within the 80-123℃range.Heat loss in lubricating oils was found to be the main form of heat loss,increasing from 0.5 to 1.05 kW.In addition,an increase in the inlet temperature would lead to a greater expansion ratio of the single screw expander,eventually leading to an increase in the output power.On the contrary,the proportion of each heat loss decreased.In particular,the shell and lubricating oil heat loss ratio decreased from 5.1%to 2.5%and from 16.1%to 9.5%,respectively,when the inlet temperature increased from 80℃to 123℃.This indicates that with an improvement in the performance of the single screw expander,even when the heat loss increased,its effect on the performance of the expander tend to decrease gradually.