多排气雾冲击射流换热过程的试验研究

Experimental investigation into the heat transfer process of multiple mist impinging jets

气雾冷却是带钢连续镀锌后的一种强化冷却方式。气雾冷却装置的设计和运行的关键是掌握气雾换热系数。采用试验方法研究了多排气雾射流冷却高温钢板的换热系数,考察了喷气流量和喷水流量对换热系数的影响。试验结果表明：喷气流量对气雾换热系数影响可以忽略;喷水流量对换热系数影响显著,在喷水流量为0.96～1.59 m^3/h时,换热系数随喷水流量的增加而明显上升,最大可达5 650 W/（m^2.K）;喷雾冷却的换热系数远大于常规喷气冷却,能有效地强化镀后冷却。

Mist jet impingement cooling is an enhanced heat transfer method widely used after the continuous galvanizing process.The key of a successful design and operation of the mist jet impingement cooling lies in mastering heat transfer coefficients.The heat transfer coefficients of high temperature steel plates cooled with multiple mist impinging jets were investigated using experimental methods,and the effects of gas and water flow rates on heat transfer coefficients were observed and studied.The test results illustrate that the gas flow rate has little effect on the mist heat transfer rate.It is also found that the water flow rate has a great impact on the heat transfer coefficient.When the water flow rate ranges from 0.96 m3/h to 1.59 m3/h,an increase of the rate will produce a higher heat transfer coefficient,the maximum of which will reach 5 650 W/（m2·K）.Compared with the conventional gas jet cooling,heat transfer coefficients of the mist jets will be much higher,which can effectively strengthen the after-pot cooling.