Laminar Pulsed Forced and Mixed Convection in a Vertical Isothermal Tube
Laminar Pulsed Forced and Mixed Convection in a Vertical Isothermal Tube
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垂直等温管中的层流脉冲强制对流和混合对流
DOI：
10.2514/2.6257
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发表时间：
1997
影响因子：
2.1
通讯作者：
S. Inamdar
中科院分区：
文献类型：
--
作者：
T. Myrum;S. Acharya;S. Inamdar
数值流体流动和传热的结果，获得了脉冲层流通过垂直，等温壁管Gr/Re = 0（无浮力）和30（浮力）在循环平均雷诺数为5 × 10 - 2。脉动导致循环平均努塞尔数Nu av大于稳定的、充分发展的层流努塞尔数，Nu av随着频率的增加而增加。对于Gr/Re - 0，努塞尔数也随着振幅a的增加而增加，但对于Gr/Re - 30，努塞尔数在a - 0.1以上几乎保持不变。虽然在Gr/Re = 30时的NVav值大于Gr/Re = 0时的值，但它们被相对较大的循环平均无因次壁面剪应力τ av值所抵消。对于Gr/Re = 30，Nuav/τ av等于或小于稳定的充分发展层流。相反，当Gr/Re = 0时，Nu av /τ av增加多达39%。
Numerical fluid flow and heat transfer results were obtained for a pulsed laminar flow through a vertical, isothermal-walled tube for Gr/Re = 0 (no buoyancy) and 30 (buoyancy) at a cyclic-averaged Reynolds number of 5 x 10 2 . The pulsations resulted in cyclic-averaged Nusselt numbers Nu av that were greater than the steady, fully developed laminar Nusselt number, with Nu av increasing with increasing frequency. The Nusselt number also increased with increasing amplitude a for Gr/Re - 0, but it remained virtually constant beyond a - 0.1 for Gr/Re - 30. Although the NV av values at Gr/Re - 30 were greater than at Gr/Re = 0, they were offset by relatively large values of the cyclic-averaged dimensionless wall shear stress τ av , For Gr/Re = 30, Nu av /τ av was either the same or less than that for steady, fully developed laminar flow. Conversely, Nu av /τ av increased by as much as 39% for Gr/Re = 0.