In the present work, experimental and numerical thermal analysis of a microhotplate were performed to evaluate the heat transfer mechanism at small Rayleigh number ( $Ra$ ). The convective and radiative heat transfer coefficient values were evaluated for microhotplate mounted over two different mounting positions (namely model-1 & model-2). At different heat generation ( $Q$ ) values, it was found that the average convective coefficient value was less than $10\frac {W}{m^{2}K}$ , irrespective of the microhotplate mounting position. Comparison of both models at a similar $Q$ ( $\simeq 0.69W$ ) value, reveals that the radiative heat transfer contribution was 33% & 68% for model-1 and model-2 respectively. Based on the results obtained in the present study, a correlation was developed using regression analysis for the convective Nusselt number in terms of Rayleigh number ( $8.84\times 10^{-4}\le \:Ra\:\le 4.94\times 10^{-3}$ ), and the convective Nusselt number obtained from the correlation and present study are within ±17%.

中文翻译：

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Microhotplate 的热分析 - 一项实验研究

在目前的工作中，对微热板进行了实验和数值热分析，以评估小瑞利数下的传热机制（ $Ra$ ）。对安装在两个不同安装位置（即模型 1 和模型 2）上的微型加热板的对流和辐射传热系数值进行了评估。在不同的发热量（ $Q$ ) 值，发现平均对流系数值小于 $10\frac {W}{m^{2}K}$ ，无论微加热板的安装位置如何。两种模型在相似的情况下的比较 $Q$ ( $\simeq 0.69W$ ) 值，表明模型 1 和模型 2 的辐射传热贡献分别为 33% 和 68%。基于本研究中获得的结果，使用瑞利数对对流努塞尔数的回归分析建立了相关性（ $8.84\times 10^{-4}\le \:Ra\:\le 4.94\times 10^{-3}$ )，并且从相关性和本研究中获得的对流努塞尔数在 ±17% 以内。