Maximum heat flux at wetting front and velocity of the front during quenching of high temperature material temperature material

高温材料的冷却问题普遍存在于金属加工、反应堆冷却剂损失安全管理等工程领域。热传递强烈地依赖于表面是否润湿，其数值通常会变化一百次。高温材料在淬火过程中，传热过程一般由膜沸腾转变为核态沸腾。在这项研究中，首先利用拉普拉斯变换建立了二维逆解来估计表面温度和热流密度。将新提出的逆解应用于移动热源进行了数值校核，得到了在与固体温度测量精度几乎相同的情况下估算表面温度和热流密度，进而确定移动热源位置的方法。实验研究了高温铜、黄铜和钢在冲击液体射流淬火过程中的润湿前沿速度和换热特性。试验范围列在表中。通过将逆解应用于该淬火，可以得到淬火过程中高温表面被润湿的位置，并在该位置获得最大热流密度。用高速摄像机将估算的位置与测量的位置进行了比较，吻合较好。通过实验，明确了液体温度、液体速度、材料热物性对湿润锋速度和最大热流密度的影响。

The cooling of high temperature material commonly appears in engineering field such as metal processing and safety management for loss of coolant in reactor. Heat transfer strongly depends on whether the surface is wetted or not and its values usually changes one hundred times. During quenching the high temperature material, in general, heat transfer process changes from film boiling to nucleate boiling through transition boiling. In this study, two-dimensional inverse solution is first developed using the Laplace transformation to estimate the surface temperature and heat flux. The newly developed inverse solution is numerically checked in application to the moving heat source and it is found for the solution to estimate the surface temperature and heat flux with almost the same accuracy of the measured temperature in solid and then to determine the location of the moving heat source.Experiment has been conducted to make characteristics of the wetting front velocity and heat transfer during the quench of high temperature copper, brass and steel with an impinging liquid jet. Experimental range is listed in table. By applying the inverse solution to this quench, the location at which the high temperature surface is wetted during quenching can be obtained and the maximum heat flux at this location can be obtained. The estimated location is compared with the measured position using high speed video camera, being in good agreement. The effect of liquid temperature, liquid velocity, thermal properties of material on the wetting front velocity and the maximum heat flux are made clear, experimentally.【table】