冷却温度对平板脉动热管传热特性影响的试验研究

Experimental study on the effect of cooling temperature on heat transfer characteristics of flat pulsating heat pipe

为了探究冷却温度与脉动热管传热性能的关系,以氟代醚HFE-7100,HFE-7300和HFE-7500为工质,改变冷却水浴温度及加热功率,试验研究了加热功率与冷却温度对脉动热管传热的综合影响。结果显示,沸点更低的HFE-7100及HFE-7300脉动热管在30~50 W成功启动,适用于低加热功率,而沸点更高的HFE-7500适用于高加热功率(110~170 W);当给定加热功率或冷却温度时,分别存在一个最佳冷却温度或加热功率使得脉动热管传热性能最优,因此应根据脉动热管的加热功率及运行温度区间合理选择工质。氟代醚脉动热管受冷却温度的影响较大,高冷却温度下过渡时间明显增加;受沸点影响,HFE-7500过渡时间变化相对较小。高加热功率下,冷却温度对脉动热管的影响减小,过渡时间也减少。低加热功率配合较高冷却温度及高加热功率配合较低冷却温度均可使脉动热管达到最佳运行状态,不同的是低加热功率下脉动热管的最佳运行区间较小,高加热功率下最佳运行区间增大。

In order to explore the relationship between cooling temperature and heat transfer performance of pulsating heat pipe(PHP),taking fluoroethers HFE-7100,HFE-7300 and HFE-7500 as working fluids.The comprehensive effect of cooling water temperature and heat input on the heat transfer of PHP is experimentally studied.The results show that HFE-7100 and HFE-7300 PHPs with lower boiling point were successfully started at 30~50 W and are suitable for low heat input,while HFE-7500 with higher boiling point is suitable for high heat input(110~170 W).When the heat input or cooling temperature is given,there is an optimal cooling temperature or heat input to optimize the thermal performance.Therefore,the working fluid should be reasonably selected according to heat input and operating temperature range.The fluoroethers is greatly affected by cooling temperature,and the transition time increases significantly at high cooling temperature,while the transition time of HFE-7500 changes relatively little due to the influence of boiling point.Under high heat input,the influence of cooling temperature on PHP will be reduced and the transition time will be reduced.Low heat input combined with high cooling temperature and high heat input combined with low cooling temperature can make the PHP achieve the best operation state.The difference is that the optimum temperature range of PHP is shorter under low heat input and increases under high heat input.