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Experimental investigation of hydronic air coil performance with nanofluids
International Journal of Heat and Mass Transfer ( IF 5.2 ) Pub Date : 2018-09-01 , DOI: 10.1016/j.ijheatmasstransfer.2018.02.112
Roy Strandberg , Debendra Das

Abstract The objective of this study is to experimentally characterize and compare the performance of a nanofluid comprised of Al2O3 nanoparticles with 1% volumetric concentration in a 60% ethylene glycol/40% water (60% EG) solution to that of 60%EG in a liquid to air heat exchanger. The test bed used in the experiment was built to simulate a small air handling system typical of that used in HVAC applications. Previously established empirical correlations for thermophysical properties of fluids were used to determine the values of various parameters (e.g. Nusselt number, Reynolds number, and Prandtl number). The testing shows that the 1% Al2O3 nanofluid generates a marginally higher rate of heat transfer than the 60% EG under certain conditions. At Re = 3000, the nanofluid produced a rate of heat transfer that was 2% higher than that of the 60% EG. The empirically determined Nusselt number associated with the convection in the coil tubing for the nanofluid follows the behavior predicted by the Dittus-Boelter correlation (R2 = 0.97), while the empirically determined Nusselt number for the 60% EG follows the Petukhov correlation similarly (R2 = 0.97). Pressure loss and hydraulic power for the nanofluid were higher than for the base fluid over the range of conditions tested. The exergy destroyed in the heat exchange and fluid flow processes were between 9% and 12% lower for the nanofluid than the base fluid over the tested range of Reynolds numbers.

中文翻译:

纳米流体循环空气线圈性能的实验研究

摘要 本研究的目的是通过实验表征和比较由体积浓度为 1% 的 Al2O3 纳米粒子在 60% 乙二醇/40% 水 (60% EG) 溶液中的纳米流体与 60% EG 的纳米流体的性能。液体空气热交换器。实验中使用的测试台用于模拟典型的 HVAC 应用中使用的小型空气处理系统。先前建立的流体热物理特性的经验相关性用于确定各种参数的值(例如努塞尔数、雷诺数和普朗特数)。测试表明,在某些条件下,1% Al2O3 纳米流体产生的传热率略高于 60% EG。在 Re = 3000 时,纳米流体产生的传热率比 60% EG 高 2%。与纳米流体盘管中的对流相关的经验确定的努塞尔特数遵循 Dittus-Boelter 相关性预测的行为 (R2 = 0.97),而经验确定的 60% EG 的努塞尔特数同样遵循 Petukhov 相关性 (R2 = 0.97)。在测试条件范围内,纳米流体的压力损失和液压功率高于基础流体。在雷诺数的测试范围内,纳米流体在热交换和流体流动过程中破坏的火用比基础流体低 9% 到 12%。而经验确定的 60% EG 的努塞尔数也类似地遵循 Petukhov 相关性 (R2 = 0.97)。在测试条件范围内,纳米流体的压力损失和液压功率高于基础流体。在雷诺数的测试范围内,纳米流体在热交换和流体流动过程中破坏的火用比基础流体低 9% 到 12%。而经验确定的 60% EG 的努塞尔数也类似地遵循 Petukhov 相关性 (R2 = 0.97)。在测试条件范围内,纳米流体的压力损失和液压功率高于基础流体。在雷诺数的测试范围内,纳米流体在热交换和流体流动过程中破坏的火用比基础流体低 9% 到 12%。
更新日期:2018-09-01
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