地下建筑空调排风热回收用两侧旋转布水间接蒸发冷却器强化传热机理优化分析及应用研究

The indirect evaporative cooler’s is widespread used in building thermal environment and energy field,and the heat and moisture transfer mechanism is the foundation to improve its performance. Not only is the current researches are limited to enhance the heat and mass transfer by distributing water on the top of coil ,but also ignore the influence of the water film velocity. In order to maximum make use of the heat transfer ability between the inlet air and the water film, the applicant put forward rotary spraying cooling on both sides of each heat exchanger unit,which consists of two groups cross-arranged bundles,and a number of heat exchanger unit operate in parallel to constitute the heat exchanger coil. This project will study the heat and moisture transfer mechanism of the heat exchanger by means of experiment and numerical simulation. Using particle image velocity meter and particle size analyzer to measure the water droplet diameter, velocity and distribution uniformity, and using the water film thickness detection device and high-speed camera to analyze the water film uniformity,velocity ,and therefore to reveal the influence of water distribution parameters on the water film uniformity and velocity,such as the water droplet diameter, the water droplet velocity,the distance between the adjacent nozzle and the rotate spray cycle ; Using the VOF model to research the transient heat transfer process between the wall and water film ,and acquire the heat transfer coefficient accordingly;Analyzing the heat entransy and the moisture entransy of the air in the heat and mass transfer process, consequently, to reveal objective law of the heat and mass transfer mechanism between the water film and air,which influenced by the spray water distribution parameters,and to establish the mathematical model and optimization design method, These reaearches are of great significance for developing new high-efficiency heat exchanger ,and providetheoretical foundation.

间接蒸发冷却器广泛应用于建筑热环境和能源领域，对其热湿传递机理的研究是提高性能的基础，目前多在盘管顶部布水方式下强化传热传质，且忽略水膜流速的影响。申请人提出以两组叉排盘管为一个换热单元，在每个换热单元两侧旋转布水，若干个换热单元并联设置，构成两侧旋转布水间接蒸发冷却器，以最大限度利用水膜与空气的传热传质能力。本项目采用实验和数值模拟方法研究其热湿传递机理，利用粒子图像速度仪和粒度仪测定喷水区液滴粒径、速度分布均匀性，以水膜厚度检测装置和高速摄像机分析水膜均匀性和流速，揭示喷嘴间距、布水周期等参数对水膜均匀性、流速的影响，利用VOF模型分析液滴撞击壁面时水膜与壁面瞬态传热机理，得到水膜与壁面的表面传热系数，通过分析热湿转换过程的空气热“积”和湿“积”，最终揭示布水参数对水膜与空气的热湿转换过程的影响规律，建立预测冷却器性能的数学模型和优化设计方法，为开发高效间接蒸发冷却器提供理论基础。

蒸发冷却器由于其节能、高效的特性，被广泛应用于各个领域的空调系统，本课题针对地下建筑（地下车站、军事基地）空调系统设置冷却塔的可靠性、协调性和隐身性的要求，及其空调工程造价、运行能耗高昂的问题，结合其可回收利用其坑道排风能量的有利条件，基于改善水膜性能、提高水膜与壁面换热系数、优化水膜与空气传热传质的空气热"积"和湿"积"转换过程、最大限度利用水膜与空气的传热传质能力的原理，以两组叉排盘管为一个换热单元，在每个换热单元两侧旋转布水，将若干个换热单元并联构成冷却器，开发了两侧旋转布水间接蒸发冷却器等系列设备；通过粒子图像速度仪、粒度仪和水膜厚度检测系统，研究了水膜分布特性；利用VOF模型分析了液滴撞击壁面时水膜与壁面瞬态传热机理；研究了水膜与空气传热传质过程的空气热" 积"和湿"积"转换机理。本课题所开发系列技术获2015年湖南省技术发明奖，且成功应用于多个地下工程，课题组现已授权发明专利2项，实用新型专利1项，发表论文16篇,其中SCI4篇、EI5篇、CSCD5篇，培养硕士研究生4名(毕业２名，在读２名)。本课题研究成果对揭示两侧旋转布水间接蒸发冷却传热传质机理、开发应用新型高效换热器及推进节能减排具有重要意义。