Investigation of the transient heat transfer to a supersonic air jet impinging on a high-temperature plate based on a discrimination-experiment method.

Ming-Xin Gao,Yue Zhang,Hua Song,Jian Yang,Mohammad Mehdi Rashidi

doi:10.1371/journal.pone.0264968

Ming-Xin Gao, Yue Zhang + Show 3 more

Open Access

https://doi.org/10.1371/journal.pone.0264968

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Abstract

A discrimination-experiment method is developed to investigate the transient heat transfer of air jet impingement by discretizing the solid domain into mutually adiabatic test cylinders. This method can not only reduce the influence of the transverse heat transfer of a solid domain on the heat transfer characteristics of the jet but can also simplify the two-dimensional or three-dimensional heat conduction problem into a one-dimensional problem. Moreover, the discrimination-experiment method eliminates the embedment of thermocouples into the solid domains, further improving the accuracy and reliability of the proposed method. The transient heat transfer characteristics of a supersonic air jet impinging on a high-temperature target (860°C) and the effects of thermo physical parameters, such as the density, specific heat capacity, thermal conductivity and nozzle-to-target distance (H/D = 3, 4, and 5) are analyzed in detail using the discrimination-experiment method. The results provide important guidance for the thermal design of supersonic air jet impingement.

Highlights

IntroductionJet impingement is an extremely effective method to enhance the heat transfer by spraying the desired fluid on the target surface
With compressed air as a medium, the air jet impingement has been widely used in a wide range of heat transfer applications, such as the cooling of electronic components, surface strengthening treatments of steel or glass, and forced cooling of power plants, due to its environmentally friendly nature, high heat transfer efficiency, and excellent cooling uniformity
Hvar y represents the convective heat transfer coefficient when all three parameters are vary with temperature

Summary

Introduction

Jet impingement is an extremely effective method to enhance the heat transfer by spraying the desired fluid on the target surface. With compressed air as a medium, the air jet impingement has been widely used in a wide range of heat transfer applications, such as the cooling of electronic components, surface strengthening treatments of steel or glass, and forced cooling of power plants, due to its environmentally friendly nature, high heat transfer efficiency, and excellent cooling uniformity. The utilization of a pulse air jet can improve the heat transfer capacity by 85%, but it still cannot meet the practical requirements [3, 4]. Another way to enhance the heat transfer capacity of air jets is to increase the jet velocity.

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Conclusion