【摘要】 为了分析内燃机缸盖鼻梁区水腔局部真实的传热状况,以某大功率六缸天然气发动机为研究对象,在不同转速、不同工作负荷、不同冷却水温度和不同冷却水系统压力的工况条件下,对缸盖鼻梁区位置进行定点测温试验,并通过试验数据分析得出其测点位置处水腔壁面的传热状况及缸盖测点温度变化趋势。研究结果表明:在大扭矩高负荷工况条件下,鼻梁区水腔壁面处传热特性曲线非线性关系,基本处于过冷沸腾状态,与小扭矩低负荷下的单相对流传热相比,其传热强度更为剧烈;随着冷却水温度的增加,发动机缸盖测点温度整体提高,但各测点变化大小存在一定差异;提高冷却水系统压力,其测点温度也有明显升高。更多还原

【Abstract】 In order to analyze the heat transfer characteristics in cylinder head water jacket around the valve bridges,a six-cylinder heavy-duty natural gas engine was used to measure the temperatures of such areas under different speed and load,as well as different coolant temperature and pressure.Heat convection and boiling heat-transfer as well as temperature change in the measured areas were obtained through the analysis of the measurement.The analysis result shows that nucleate boiling state exists around the valvebridge where heat transfer characteristic is no longer in linear when the engine works under high load and large-torque and heat transfer is more intensified compared with only heat convection when the engine works under low load.With the coolant temperature increasing,the temperature of each measured point in engine cylinder head rises differently,and the same results are found when rising coolant pressure.更多还原