针对蒸发冷却设备研究羽雾产生的机理,设计并研制了一种间壁式气-气换热器型的收水器,兼作消雾装置,湿热空气与环境冷风在其间换热后降温析湿,两股空气混合后达到的状态点在饱和线或者不饱和区,从而实现消雾的目的。多组实验观察及分析表明:该消雾装置能够有效消除羽雾,回收湿热空气带走的水分;并且在未增加蒸发冷却设备气侧阻力的情况下,原冷却设备热力性能也没有降低,实验工况下的激光透过率提升9%至零雾。

Droplet evaporation is a common physical phenomenon, widely used in the life, science, industry and other fields. During evaporation of the droplets, the surface tension changes due to the non-uniformity of vapor-liquid interface temperature, and the Marangoni convection is generated. Previous studies mainly focused on constant wall temperature condition, but less on constant heat fluxes condition. In this paper, a 5μl R113 sessile droplet evaporated on a hydrophilic heating surface with a constant heat flux ranging from 0~3575W/m² was studied. A high-speed camera and an infrared camera were used to record the dynamic characteristics of the droplet evaporation phenomenon in the horizontal and vertical directions respectively. The Marangoni phenomenon of losing stability, evaporation time, the dynamic contact angle, the number of ripples, cell body diameter were present in this paper.
© 2020 Elsevier Ltd

将激光干涉法和高速摄像技术相结合,研究了疏水ITO加热表面生成的单个乙醇气泡的动态特性,观测研究了其底部的微液层,并与之前的亲水加热表面的气泡生长脱离过程进行对比分析。本实验同时使用两台高速摄像机:一台记录气泡底部微液层干

为了揭示电场对自然对流换热的影响,采用高速摄影技术对R113工质在自然对流区的电对流强化换热现象进行了实验研究,高压电源1~5 kV、热流密度4.46~17.80 kW/m^2,分析了电对流层高度、加热面温度、对流换热系数以及电场的强化换热系数的

针对某个恒定热源的待冷却工况,设计了4种散热的车载冷却方案,以应对原有冷却系统因紧急灾害失效致热量积聚从而使冷却水池沸腾产生极端事故的情况,并对各个方案运行过程中动态的空间散热比、造价散热比、风量散热比和水耗散热比进行综合分析,得出各个方案的劣势因子。结果表明:空冷器与蒸发冷却器串联方案稳定运行时段比降温运行时段劣势因子增加了7.43%;两级蒸发冷却器串联但前级蒸发冷却器先期不喷淋方案随着水池温度的稳定,劣势因子下降10.53%;回水预冷后全部蒸发冷却器方案的劣势因子总体最小,故此方案为允许一定水耗条件下技术经济性最好的方案;在无补充水条件下,全空冷方案虽然空间散热比、造价散热比和风量散热比均最高,但水耗散热比为零,此方案具有不可替代性。

The laser interferometric method and high-speed camera techniques are used simultaneously to study dynamic characteristics of a single vapor bubble growth and departure from an ITO heater surface submerged in ethanol. Two high-speed cameras are used simultaneously in this experiment: one is used to record interference fringes of the microlayer at the bubble's bottom and the other is used to record the growth and detachment of the single bubble synchronously from the side view. By comparing these images frame by frame, it is found that the bubble's growth time can be divided into two periods sequentially: the microlayer period and the lateral rewetting period. Variations of dry spot radius, bubble contact radius, bubble volume and diameter, dynamic contact angles during these two periods are illustrated.
© 2019 Elsevier Ltd

In this paper, the electrohydrodynamic (EHD) enhancement of free convection heat transfer is studied experimentally. A smooth copper heating surface is submerged in R113 liquid, the heat fluxes ranging from 4461 W/m² to 17805 W/m², and a high voltage ranging from 1 kV to 5 kV are applied on the heating surface. High speed photography is used to record the images of electroconvection. The results show the relationship between the intensity of the electric field, the height of the electroconvection layer and the enhancement of the heat transfer coefficient. Electric field can enhance free convection heat transfer, with the increase of the electric field the fluid disturbance on the heating surface increases obviously, and with the increase of the heat fluxes the enhancement of electric field gradually decreases.
© 2019 Elsevier Inc.

Closed-circuit cooling tower (CCT) using plastic capillary mats as heat exchanger can solve two important problems i.e. frozen and corrosion. Besides it has advantages of less tube weight, low noise, and inhibition scale. In this paper a CCT using polyethylene (PE) capillary mats as heat exchanger was designed and tested. Results show that traditional equations of evaporation cooling can be used to calculate the performance of closed-circuit cooling towers (CCTs) using plastic capillary mats. On this basis, comparisons of the heat dissipating capacity and cost was made about CCTs using five kinds of heat exchangers (exchangers with capillary mats of PE, thermally conductive polyethylene (TPE) and thermally conductive polypropylene (TPP), stainless-steel tubes and copper tubes respectively). Their heat dissipating capacity ratio of five CCTs is 66:83:89:96:100. Their cost ratio is 103:125:174:86:100. The paper also proved that CCTs with plastic capillary mats have better technical and economic performance.
© 2019 Elsevier Ltd

分析了空气源塔式换热热泵/制冷系统核心部件之一的吸热塔的技术特点,并选取开式横流冷却塔作为向吸热塔改造的对象,对其进行结构改造,最后进行了实验测试和分析。结果表明:通过特殊设计和改造后的吸热塔解决了原有金属塔体被腐蚀的缺陷;噪声较小;很大程度上防止了塔内溶液的飘移和外溅以及雨水落入塔内稀释溶液的问题;具有良好的换热性能。

In previous researchers' studies, the evaporation of droplets were conducted on heating surfaces with constant wall temperature. However, no previous experiments were carried out on a constant heat flux heating surface. The evaporation of 3 μl sessile droplets on hydrophilic and hydrophobic heating surface with constant heat fluxes were observed and recorded by a high-speed photography. The evaporation time, dimensionless contact angle, dimensionless contact diameter and height were presented. The evaporation rate of the droplet on the hydrophilic surface was faster than that on the hydrophobic surface, and with the increase of the heat fluxes, the evaporation rate of the droplet increases. For both hydrophilic and hydrophobic surface, the evaporation mainly followed the CCR mode, and there was a mixed evaporation mode at the later stage of evaporation, but no CCA mode was found in the whole process.
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