The numerical model investigated in this paper was implemented with Finite Element Method (FEM) based Comsol Multiphysics software, starting from a real cross-flow micro heat exchanger manufactured from 50 stainless steel plates for cold and hot fluid transfer. Each plate (foil) had 34 microchannels with rectangular cross-section, at a depth of 100 μm and a width of 200 μm. The working fluids were water and Al2O3-water nanofluids with volumetric concentrations of 0.5%, 1% and 1.5% in the temperature domain of 293 - 333 K. The oxide-based nanofluids are widely investigated in thermal energy transfer applications due to an increased heat transfer performance by comparing with pure water as a cooling fluid. Analytical models for the physical properties of water and nanofluid, referring to density, viscosity, thermal conductivity and specific heat capacity were used here. MicroChannel bulk temperature profiles for cold and hot plates of the model with 1 % Al2O3-water nanofluid were presented here in order to examine the uniformity of temperature distribution in the channel flow field area. Simulation results indicated that the total heat flow rate in the heat exchanger models increased with the increase in volume concentration of the nanoparticles at mass flow rates of 41, 61, 81, 101 and 150 Kg/h, but with the expense of a bigger pressure drop (or Fanning friction factor) at an increased pumping power required to drive flow through the channels.
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机译：本文研究的数值模型采用了基于有限元方法（FEM）的COMSOL多体声软件，从50个不锈钢板制成的真实横流微型热交换器，用于冷热流体转移。每个板（箔）具有34微通道，具有矩形横截面，深度为100μm，宽度为200μm。在293-333k的温度域中的体积浓度为0.5％，1％和1.5％的体积浓度为水和Al 2 O 3水纳米流体。由于热量增加，氧化物基纳米流体被广泛研究了热能传递应用中通过与纯水作为冷却液进行比较来传递性能。这里使用了水和纳米流体物理性质的分析模型，参考密度，粘度，导热率和特定的热容量。本文介绍了具有1％Al 2 O 3水纳米流体的模型的冷热板的微通道散装温度曲线，以检查通道流场区域中温度分布的均匀性。仿真结果表明，热交换器模型中的总热流速率随着41,61,81,101和150 kg / h的质量流速的纳米颗粒的体积浓度的增加而增加，但牺牲了更大的压力下降（或扇动摩擦系数）以增加驱动流过通道所需的泵送电力。
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