In this study, convective heat transfer performance of a nanofluids containing graphite is studied in an industrial microchannel. In the experiments, initially, to prepare nanofluids at the volume fraction values of 0.5, 1, 1.5, 2%, distilled water has been employed as the base liquid. To provide sedimentation and stabilization of nanofluids in distilled water, Cetyltrimethylammonium bromide (CTAB) is utilized as surfactant. Thermophysical properties of nanofluids such as thermal conductivity, dynamic viscosity, and specific heat are determined experimentally. Furthermore, by building an experimental setup, in the temperature range of 20–30 °C and with temperature intervals of 2 °C, performance experiments are carried out in a microchannel of which hydraulic diameter is 1.6 × 10⁻³ m. Additionally, experiments have been conducted using nanofluids at different volumetric rates from 1 to 7 l min⁻¹, heat fluxes from 100 to 1100 W, and volume fractions from 0.5 to 2%. Measuring heat flux, temperature, and flow rate, outcomes such as convective heat transfer coefficient, Reynolds number, and Nusselt number are calculated. The validation process of the experimental results has been performed by plotting the figures of Nusselt numbers vs Reynolds ones, and heat transfer coefficient vs supplied heat considering distilled water and nanofluids having various volumetric proportions. Regarding with the performance of nanofluids against distilled water under similar operating conditions, some proportional positive increase are acquired. Using outcomes attained from experiments, new correlations for Nusselt number have been derived with the R² values around 0.96, and afterward by means of those correlations experimental data have been compared with those in the literature. A large number of measured and calculated data are given in the paper for other researchers to validate their theoretical models.

中文翻译：

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微通道中包含石墨和水的纳米流体的单相流

在这项研究中，在工业微通道中研究了含有石墨的纳米流体的对流传热性能。在实验中，最初，为了制备体积分数分别为0.5、1、1.5、2％的纳米流体，已将蒸馏水用作基础液。为了提供纳米流体在蒸馏水中的沉淀和稳定作用，十六烷基三甲基溴化铵（CTAB）被用作表面活性剂。通过实验确定纳米流体的热物理性质，例如导热率，动态粘度和比热。此外，通过建立实验装置，在20–30°C的温度范围内且以2°C的温度间隔，在水力直径为1.6×10 ^-3的微通道中进行性能实验。 米 另外，已经使用纳米流体以1至7 l min ^-1的不同体积速率进行了实验。，热通量从100到1100 W，体积分数从0.5到2％。测量热通量，温度和流速，可计算出对流传热系数，雷诺数和努塞尔数等结果。考虑到蒸馏水和具有不同体积比例的纳米流体，通过绘制努塞尔数对雷诺数，传热系数对所供热量的图来进行实验结果的验证过程。关于纳米流体在类似操作条件下对蒸馏水的性能，获得了一定比例的正增加。利用实验得出的结果，已经推导了Nusselt数与R ^2的新关系。值大约在0.96，然后通过这些相关性将实验数据与文献中的数据进行比较。本文提供了大量的测量和计算数据，以供其他研究人员验证其理论模型。