Numerical Study of Mixed Convection of Buoyant Twin Jet

IF 2.8 4区工程技术 Q2 ENGINEERING, MECHANICAL

Journal of Heat Transfer-transactions of The Asme Pub Date : 2023-11-02 DOI:10.1115/1.4063959

Nassira Nouali, Mataoui Amina

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引用次数: 0

Abstract

Abstract The effect of mixed convection of twin vertical jets is investigated numerically in this paper. The results are presented specifically for turbulent flows affected by buoyancy for two parallel jets of same velocities ranging between 0,25 m/s and 5,0 m/s and temperatures between 295 K and 320 K. Both jets generate a slow flow with a temperature difference (with the ambient flow) less or equal to 32°C. The prediction of dynamical and thermal parameters are obtained in the following main characteristic regions of the two jets: the merging zone, the combining region. This study reveals that the trajectory of the two jets is strongly influenced by the ratio of buoyancy to inertial forces. Results indicate that, relative to isotherm jets, the location along the vertical symmetry plane at which the two jets merge (merging point) decreases with increasing jet inlet temperature. It was also found that the decrease in the location of the merging point is shifted towards the confining wall as the velocity of the jets increases. The behavior law (linear regression), relating to the expansion of the jet, is not verified in the whole developed region for each value of the inlet velocity and temperature. This is explained by the fact that natural convection is predominant than forced convection. Results reveal that the self-similarity of the cross profiles of the mean velocity and the law of behavior relating to the expansion of the jet are checked throughout the developed region.

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浮力双射流混合对流的数值研究

摘要本文对双垂直射流混合对流的影响进行了数值研究。在温度为295 K和320 K之间，速度为0.25 m/s和5.0 m/s的两个平行射流受浮力影响的湍流中，给出了具体的结果。两种射流都产生慢流，温差(与周围气流)小于或等于32°C。在两个射流的主要特征区域:合并区和合并区，得到了动力学和热参数的预测。该研究表明，两股射流的轨迹受到浮力与惯性力之比的强烈影响。结果表明，相对于等温射流，随着入口温度的升高，两束射流在垂直对称面上合并的位置(合并点)减小;还发现，随着射流速度的增加，合并点位置的减小向围壁偏移。对于入口速度和温度的每个值，与射流膨胀有关的行为规律(线性回归)并没有在整个发达区域得到验证。这可以用自然对流比强迫对流占优势这一事实来解释。结果表明，在整个发达地区，平均速度横剖面的自相似性和与射流膨胀有关的行为规律得到了检验。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of Heat Transfer-transactions of The Asme 工程技术-工程：机械

自引率

0.00%

发文量

182

审稿时长

4.7 months

期刊介绍： Topical areas including, but not limited to: Biological heat and mass transfer; Combustion and reactive flows; Conduction; Electronic and photonic cooling; Evaporation, boiling, and condensation; Experimental techniques; Forced convection; Heat exchanger fundamentals; Heat transfer enhancement; Combined heat and mass transfer; Heat transfer in manufacturing; Jets, wakes, and impingement cooling; Melting and solidification; Microscale and nanoscale heat and mass transfer; Natural and mixed convection; Porous media; Radiative heat transfer; Thermal systems; Two-phase flow and heat transfer. Such topical areas may be seen in: Aerospace; The environment; Gas turbines; Biotechnology; Electronic and photonic processes and equipment; Energy systems, Fire and combustion, heat pipes, manufacturing and materials processing, low temperature and arctic region heat transfer; Refrigeration and air conditioning; Homeland security systems; Multi-phase processes; Microscale and nanoscale devices and processes.