【摘要】配制溶质为Al2O3纳米粒子、黄原胶为分散剂, 经超声波振荡后分散均匀稳定的Al2O3-H2O纳米流体。利用真空动态喷射制冰实验装置, 设定初始压力300 Pa, 研究在有无固体吸附作用、不同纳米流体浓度、不同纳米颗粒粒径和不同供液流量下的真空闪蒸制冰特性。结果表明, 吸附作用对真空制冰系统稳压效果显著且有助于捕捉实验中的水蒸气;当冷却介质温度低于吸附剂初始温度时, 吸附剂有更好的吸附能力但冷却温度不宜过低;纳米流体浓度越大、纳米粒子粒径越小, 更利于制取高含冰率的冰浆;对于同一浓度的纳米流体, 合理控制供液流量可以获得不同含冰率的冰浆;在2% (质量) Na Cl下, 各粒径的纳米流体浓度不宜超过0.05% (质量) 。
【基金资助】 国家自然科学基金项目 (50976064, 51376115) ; 上海海事大学研究生学术新人培育项目 (YXR2017069) ;
Characteristics of dynamic ice-making via Al2O3-H2O nanofluid’s vacuum flash
【Abstract】Al2O3 nanoparticles were added into the water with xanthan to prepare the well-distributed Al2O3-H2O nanofluid with ultrasonic wave. Based on the theory of flash evaporation, the experimental apparatus of dynamic ice-making under vacuum was designed. In the same flash pressure (300 Pa), the vacuum flash experimental characteristics in different conditions, such as solid adsorption, nanofluid concentration, particle size and diaphragm metering pump flow, were investigated. The results show that the adsorption action has obvious effects on keeping the stability of the pressure and it is useful to capture the water vapor in the system. When the temperature of the cooling medium is lower than the initial temperature of the adsorbent, the adsorbent has better adsorption capacity, but the cooling temperature should not be too low. The larger concentration of the nanofluid and the smaller particle size are better for getting the high ice packing factor of ice slurry. For the same concentration of nanofluid, the ice packing factor of ice slurry can be gotten by reasonable control of the diaphragm metering pump flow. In 2% (mass) NaCl, the concentration of nanofluid in different particle sizes should not exceed 0.05% (mass).
【Keywords】 nanoparticles; ice-making; vacuum; adsorption; ice packing factor; phase change;
【Funds】 National Natural Science Foundation of China (50976064, 51376115) ; Academic Training Program for Postgraduate Student of Shanghai Maritime University (YXR2017069) ;
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