Experimental and Theoretical Investigation of Microchannel Condensation Heat Transfer

微通道冷凝传热的实验与理论研究

• 批准号: EP/L001233/1
• 负责人: Hua Sheng Wang
• 金额: $ 45.94万
• 依托单位: Queen Mary University of London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FL001233%2F1
• 关键词: Experimental; Theoretical; Investigation; Microchannel; Condensation

This work is an experimental and theoretical investigation of condensation in channels having a typical cross section dimension around 1 mm. The condenser is a key component in a wide range of industrial plant such as power generation, refrigeration and air conditioning and in the process industries. Condensers employing microchannel tubes have been used successfully in automotive air conditioners for around 25 years and, while not yet optimized, have clearly demonstrated the effectiveness of this geometry resulting in condensers four times smaller and with efficiencies 10-20% higher than earlier technologies. Automotive designs are based on empirical trial-and-error methods that are feasible for small units. In order that designs may be optimised, and more importantly, that the technology may be taken up for larger scale equipment, fundamental understanding of the processes involved is needed. The proposed work will enable optimized design of larger scale condensers for a wide range of applications with vastly improved performance over plant currently in use. In refrigeration and air conditioning the improved technology could save up to 10% of the energy demand, with corresponding reduction carbon dioxide emissions, if widely used in the UK.Experimental data of sufficient accuracy have only recently become available and these are only for low surface tension fluids (synthetic refrigerants). Our earlier theory, applicable to any fluid, is in good agreement with much of these data and predicts very significantly improved performance when using higher surface tension fluids such as ammonia. The objective of the new work is to obtain results for fluids having widely different surface tensions to enable semi empirical modification of the theory and thus to provide the first reliable engineering design tools for application by numerous industries.Experimental heat transfer and pressure drop measurements of hitherto unexcelled accuracy will be made using a copper microchannel condenser block in which 98 carefully calibrated thermocouples are precisely located. The required surface temperatures and heat fluxes will be determined by the "inverse method" with accuracy 0.1 K and 5% respectively.Our earlier theory (2005) for the predominant flow regime (annular, laminar) closely predicts the most recent (2012) experimental data from other laboratories over most of the ranges of the relevant flow parameters. To date the only reliable available measurements are for low surface tension fluids typical of synthetic refrigerants. The annular laminar flow theory is valid for any fluid and predicts greatly improved performance for higher surface tension fluids such as ammonia and steam/water.Visualization tests will also be done to establish the flow regimes. These will be used, together with the heat transfer and pressure drop data, to establish the limits of validity of the annular laminar flow theory and to develop semi-empirical adjustments to the theory to cover all circumstances which may occur in practice. The project will thus provide the first reliable, widely applicable tools which will enable more confident design of the larger scale devices of greatly improved efficiency.

这项工作是一个典型的横截面尺寸约为1毫米的通道中的冷凝的实验和理论研究。冷凝器是一个重要组成部分，在广泛的工业工厂，如发电，制冷和空调，并在过程工业。采用微通道管的冷凝器已成功地用于汽车空调约25年，虽然尚未优化，但已清楚地证明了这种几何形状的有效性，从而使冷凝器比早期技术小四倍，效率高10-20%。汽车设计是基于经验的试错法，适用于小单位。为了优化设计，更重要的是，该技术可以用于更大规模的设备，需要对所涉及的过程有基本的了解。拟议的工作将使更大规模的冷凝器的优化设计，为广泛的应用，大大提高了目前使用的设备的性能。在制冷和空调方面，如果在英国广泛使用，改进后的技术可以节省高达10%的能源需求，并相应减少二氧化碳排放。足够精确的实验数据最近才出现，这些数据仅适用于低表面张力流体（合成制冷剂）。我们早期的理论，适用于任何流体，是在很好的协议与这些数据，并预测非常显着改善性能时，使用较高的表面张力的流体，如氨。新工作的目的是获得具有广泛不同表面张力的流体的结果，以使理论的半经验修正成为可能，从而为许多工业的应用提供第一个可靠的工程设计工具。实验传热和压降测量将使用铜微通道冷凝器块，其中98个仔细校准的热电偶精确地所在所需的表面温度和热通量将通过“逆方法”确定，精度分别为0.1 K和5%。我们早期的主要流态（环形、层流）理论（2005年）在大多数相关流动参数范围内准确预测了来自其他实验室的最新（2012年）实验数据。到目前为止，唯一可靠的测量方法是对合成制冷剂中典型的低表面张力流体进行测量。环形层流理论适用于任何流体，并预测对于较高表面张力的流体（如氨和蒸汽/水），其性能将大大提高。还将进行可视化测试以建立流态。这些数据将与传热和压降数据一起用于确定环形层流理论的有效性极限，并对理论进行半经验调整，以涵盖实践中可能发生的所有情况。因此，该项目将提供第一个可靠的，广泛适用的工具，这将使更大规模的设备，大大提高效率更有信心的设计。

项目成果

Parametric study on thermal and hydraulic characteristics of laminar flow in microchannel heat sink with fan-shaped ribs on sidewalls - Part 1: Heat transfer

• DOI: 10.1016/j.ijheatmasstransfer.2016.02.077
• 发表时间: 2016-06-01
• 期刊: INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
• 影响因子: 5.2
• 作者: Chai, Lei;Xia, Guo Dong;Wang, Hua Sheng
• 通讯作者: Wang, Hua Sheng

Parametric study on thermal and hydraulic characteristics of laminar flow in microchannel heat sink with fan-shaped ribs on sidewalls - Part 3: Performance evaluation

• DOI: 10.1016/j.ijheatmasstransfer.2016.02.075
• 发表时间: 2016-06-01
• 期刊: INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
• 影响因子: 5.2
• 作者: Chai, Lei;Xia, Guo Dong;Wang, Hua Sheng
• 通讯作者: Wang, Hua Sheng

Measurements for condensation of steam-ethanol mixtures in microchannel

微通道中蒸汽-乙醇混合物的冷凝测量

• 发表时间: 2018
• 作者: Chai L

Advances in Heat Transfer and Thermal Engineering - Proceedings of 16th UK Heat Transfer Conference (UKHTC2019)

传热与热工程进展 - 第 16 届英国传热会议 (UKHTC2019) 论文集

• DOI: 10.1007/978-981-33-4765-6_24
• 发表时间: 2021
• 作者: Agrawal P

Laminar flow and heat transfer characteristics of interrupted microchannel heat sink with ribs in the transverse microchambers

横向微腔肋间断微通道散热器层流及传热特性

• DOI: 10.1016/j.ijthermalsci.2016.06.029
• 发表时间: 2016-12-01
• 期刊: INTERNATIONAL JOURNAL OF THERMAL SCIENCES
• 影响因子: 4.5
• 作者: Chai, Lei;Xia, Guo Dong;Wang, Hua Sheng
• 通讯作者: Wang, Hua Sheng