低流阻火箭煤油的超临界压力流动与换热特性

Flow and Heat Transfer Characteristics of Low-Flow Resistance Rocket Kerosene under Supercritical Pressure

为探索超临界压力下减阻剂对高温火箭煤油的减阻效果,在压力为15 MPa、质量流速为17 000～50 000kg·m-2·s-1(对应常温流速约20～60m·s-1)、流体温度从常温至360℃和热流密度为2.5～30MW·m-2的试验条件下,对火箭煤油和添加减阻剂的低流阻火箭煤油在直径2mm×0.5mm的高温合金钢管内的流动与换热特性进行了研究。研究发现:在本文研究条件下,煤油传热机理为超临界压力单相类液态强制对流换热;减阻剂对火箭煤油的减阻效果明显,减阻率最高可达60%;随着流体温度升高,雷诺数增大,减阻剂的减阻效果降低,减阻率最低下降至约20%;添加减阻剂后,煤油传热性能显著弱化,但高雷诺数下减阻煤油的换热性能基本维持不变,减阻煤油与火箭煤油的努塞尔数之比约为0.5;雷诺数小于63 000时减阻效果大于传热弱化效果,大于63 000时结果相反。

To explore the drag reduction effect of drag reducer on rocket kerosene under supercritical pressure and high temperature conditions,flow and heat transfer characteristics of rocket kerosene M and low-flow resistance rocket kerosene M-3 with drag reducer were investigated in a Φ2 mm×0.5 mm high-temperature alloy steel tube as active cooling channels.Experiments were conducted at pressure of 15 MPa,mass flow rates of 17000-50000 kg/(m^2·s)(corresponding to the normal temperature flow rates of about 20-60 m/s),and heat flux range of 2.5-30 MW/m^2.It indicated that:① The heat transfer mechanism of the rocket kerosene under the test conditions was supercritical liquid-like forced convection heat transfer;② The drag reducing effect of drag reducer on rocket kerosene was obvious,the maximum drag reducing rate reached up to 60%,and with the increase of fluid temperature,the Reynolds number increased,the drag reduction effect decreased,and the minimum drag reducing rate approached 20%;③ For the rocket kerosene with drag reducing agents,the heat transfer reduction occurred significantly,however,the heat transfer performance of kerosene M-3 hardly changed in high Reynolds number conditions,and the Nusselt number ratio of M-3 to M kept at about 0.5;and ④ When the Reynolds number was below 63000,the drag reduction was greater than the heat transfer reduction,while when the Reynolds number was greater than 63000,the results reversed.