Heat transfer enhancement in annular flow with outer grooved cylinder and rotating inner cylinder: Review and experiments
Heat transfer enhancement in annular flow with outer grooved cylinder and rotating inner cylinder: Review and experiments
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DOI：
10.1016/j.applthermaleng.2017.03.095
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发表时间：
2017-06
影响因子：
6.4
通讯作者：
A. Nouri-Borujerdi;M. E. Nakhchi
中科院分区：
文献类型：
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作者：
A. Nouri-Borujerdi;M. E. Nakhchi
本实验旨在找出影响外槽筒和旋转内筒环空流动中强化换热的最重要参数。这种类型的流被称为泰勒-库埃特流有许多工业应用，如发电机和旋转机械。一个全面的审查以前的工作，流动制度，传热和压降在沟槽通道提供。实验采用泰勒数，0< Ta< 8.36× 106；槽长径比，0< b/c< 2；槽数，0< N gr< 20，壁温，50< T w< 90℃。在4个不同的测试用例中，纵横比b/c= 2的模型的平均努塞尔数高于其他3种情况，即b/c= 0、0.5、1。研究发现，在沟槽存在的情况下，由于通道内流动的扰动和涡量，旋转通道内的热入口长度减少了17%左右。最后，根据响应面法原理对结果进行了分析。研究发现，随着槽长比和转速的增大，换热效果显著增强。
This experimental work is an attempt to identify the most significant parameters influencing heat transfer enhancement in annular flow with outer grooved cylinder and rotating inner cylinder. This type of flow known as Taylor-Couette flow has many industrial applications such as electrical power generators and rotating machineries. A comprehensive review of the previous works on flow regimes, heat transfer and pressure drop in grooved channels is provided. The experiments are conducted based on four different factors including Taylor number, 0< Ta< 8.36× 10 6; groove aspect ratio, 0< b/c< 2; number of grooves, 0< N gr< 20 and wall temperature, 50< T w< 90° C. Among four different test cases, the average Nusselt number of the model with aspect ratio b/c= 2 is higher than the other three cases, ie, b/c= 0, 0.5, 1. It is found that in the presence of grooves, the thermal entrance length in rotating channel is reduced about 17% due to perturbation and vorticity of the flow inside the channel. Finally, the results are analyzed according to the principle of response surface methodology. It is found that, heat transfer enhances significantly with increasing groove aspect ratio and rotational speed.