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Experimental Investigation of Micro Cooling Units on Impingement Jet Array Flow Pressure Loss and Heat Transfer Characteristics

Author

Listed:
  • Zhong Ren

    (Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China)

  • Xiaoyu Yang

    (Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China)

  • Xunfeng Lu

    (Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China)

  • Xueying Li

    (Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China)

  • Jing Ren

    (Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China)

Abstract

With the development in additive manufacturing, the use of surface treatments for gas turbine design applications has greatly expanded. An experimental investigation of the pressure loss and heat transfer characteristics within impingement jet arrays with arrays of target surface micro cooling units is presented. The discharge coefficient and Nusselt number are measured and determined for an evaluation of the pressure loss of the flow system and heat transfer level, respectively. Considered are effects of impingement jet Reynolds number ranging from 1000 to 15,000 and micro cooling units (square pin fin) height (h) with associated values of 0.01, 0.02, 0.05, 0.2, and 0.4 D, where D is the impingement hole diameter. Presented are variations of Nusselt number, and Nusselt number ratio, discharge coefficient, discharge coefficient ratio, discharge coefficient correlation. Depending upon the micro cooling unit height, discharge coefficient ratios slightly decrease with height, and the ratio values generally remain unit value (1.0). When Re j = 1000 and 2500 for several cooling units height values, discharge coefficient ratios show the pressure loss decreases about 2–18% and 3–6%, respectively, when compared to the data of a baseline smooth target surface plate. The observed phenomenon is due to the effects of flow blockage of micro cooing units, local flow separation, and near-wall viscous sublayer reattachment. Results also show that heat transfer levels increase 20–300% for some of the tested toughened target surface plates when compared to smooth target surface plates. The heat transfer level enhancement is because of an increase in thermal transport and near-wall mixing, as well as the increased wetted area. In addition, micro cooling units elements break the viscous sublayer and cause greater turbulence intensity when compared to the smooth target surface. Overall, results demonstrate that the target surface micro cooling units do not result in a visible increment in pressure loss and reduce pressure loss of the flow system for some of the tested patterns. Moreover, results show the significant ability of micro cooling units to enhance the surface heat transfer capability of impingement cooling relative to smooth target surfaces.

Suggested Citation

  • Zhong Ren & Xiaoyu Yang & Xunfeng Lu & Xueying Li & Jing Ren, 2021. "Experimental Investigation of Micro Cooling Units on Impingement Jet Array Flow Pressure Loss and Heat Transfer Characteristics," Energies, MDPI, vol. 14(16), pages 1-21, August.
  • Handle: RePEc:gam:jeners:v:14:y:2021:i:16:p:4757-:d:608918
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    Citations

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    Cited by:

    1. Flavia V. Barbosa & Senhorinha F. C. F. Teixeira & José C. F. Teixeira, 2021. "Experimental and Numerical Study of Multiple Jets Impinging a Step Surface," Energies, MDPI, vol. 14(20), pages 1-23, October.
    2. Linqi Shui & Zhongkai Hu & Hang Song & Zhi Zhai & Jiatao Wang, 2023. "Study on Flow and Heat Transfer Characteristics and Anti-Clogging Performance of Tree-Like Branching Microchannels," Energies, MDPI, vol. 16(14), pages 1-22, July.
    3. Ebubekir Beyazoglu & Bahadir Erman Yuce & Murat Ates & Rumeysa Yalindag & Kemal Furkan Sokmen & Erhan Pulat, 2022. "Cooling of Heated Blocks with Triangular Guide Protrusions Simulating Printed Circuit Boards," Sustainability, MDPI, vol. 14(23), pages 1-27, November.
    4. Leonid Plotnikov & Nikita Grigoriev & Leonid Osipov & Vladimir Slednev & Vladislav Shurupov, 2022. "Stationary Gas Dynamics and Heat Transfer of Turbulent Flows in Straight Pipes at Different Turbulence Intensity," Energies, MDPI, vol. 15(19), pages 1-13, October.

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