家用燃气灶具冲击射流换热的实验研究

Experimental study on impact jet heat transfer of household gas cookers

灶具强化冲击射流换热是燃气灶烟气与锅底换热的一部分。采用实验方法研究了燃气灶具中的冲击射流换热过程,主要考察了冲击射流雷诺数Re(400≤Re≤1000)、无量纲喷嘴高度H/D(2≤H/D≤10)、无量纲喷嘴间距X n/D(4≤X n/D≤15)对局部以及平均对流换热系数的影响规律。结果表明:对流换热系数h随冲击射流雷诺数的增大而增大,随着无量纲喷嘴高度增大而减小,平均对流换热系数h avg随着无量纲喷嘴间距X n/D的增大而减小。拟合出圆孔阵列中心孔局部努塞尔数Nu的实验关联式Nu=f(Re,Pr,H/D,X n/D),回归结果与实际测量值偏差在15%以内。

The heat exchange enhanced by impact jet is an important heat exchange process between the gas stove flue gas and the bottom of the pot.The heat transfer process of impact jet in gas cooker was investigated by experiments.The effects of Reynolds number of impact jet Re(400≤Re≤1000),the height of non-dimensional nozzle H/D(2≤H/D≤10),and the nozzle spacing X n/D(4≤X n/D≤15)on the local and average convective heat transfer coefficients were studied.The results show that the convective heat transfer coefficient h avg increases with the increase of the Reynolds number of the impact jet,and decreases with the increase of the dimensionless nozzle height.The average convective heat transfer coefficient h avg decreases with the increase of dimensionless nozzle spacing X n/D.The experimental correlation formula Nu=f(Re,Pr,H/D,X n/D)of the local Nusselt number Nu at the center of the circular hole array was fitted and the deviation between the regression result and the measured value was within 15%.