粗糙壁面表面传热数值计算比较
Comparative study on the numerical computation of convective heat transfer over rough surfaces
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摘要: 为了计算冰形模拟中的表面传热系数,给出了三种粗糙壁面表面传热系数计算方法,即传统的边界层积分法、基于k-ε湍流模型及标准壁面函数的计算方法(k-ε法)和基于Spalart-Allmaras湍流模型在粗糙壁面扩展的计算法(S-A扩展法).计算了直径为15cm、表面等效沙粒粗糙高度为1.35mm的圆柱,在Re分别为8.8×105,2.8×105和4.8×104时的表面传热系数.结果表明S-A扩展法与边界层积分法具有相同的趋势,在驻点附近表现出了层流特征,并与试验值吻合.在随后的湍流区域中预测值均偏大,但S-A扩展法相对更接近试验值.而k-ε法在驻点附近预测值偏大.Abstract: To compute the convective heat transfer coefficient in the ice shape simulation process,three different methods that take wall roughness into account were presented,namely,the traditional integral boundary layer (IBL) method,a method based on k-ε turbulence model plus standard wall function (k-ε method) and a method based on extension of the Spalart-Allmaras turbulence model (S-A method).The convective heat transfer coefficients were calculated for a 15cm diameter cylinder with an equivalent sand grain roughness height of 1.35mm under Reynolds numbers of 8.8×105,2.8×105 and 4.8×104 respectively.Comparisons show that IBL and S-A method have the same trends.Near the stagnation point,the predicted results show laminar features,and coincide with experimental data.Both methods overpredict the heat transfer in the following turbulent region,but S-A method agrees better with the experiment.The k-ε method overpredicts the heat transfer near stagnation region.
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Key words:
- wall roughness /
- convective heat transfer coefficient /
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