Performance evaluation of a multi-pass air-to-water thermosyphon-based heat exchanger
| Autor: | Luiz C. Wrobel, Hussam Jouhara, H. Mroue, J.B. Ramos |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Engineering
business.industry 020209 energy Mechanical Engineering Plate heat exchanger Thermodynamics 02 engineering and technology Building and Construction Heat transfer coefficient Mechanics 021001 nanoscience & nanotechnology Pollution Industrial and Manufacturing Engineering General Energy NTU method Heat transfer Heat spreader 0202 electrical engineering electronic engineering information engineering Micro heat exchanger Plate fin heat exchanger Electrical and Electronic Engineering 0210 nano-technology business Civil and Structural Engineering Shell and tube heat exchanger |
| Zdroj: | Energy. 139:1243-1260 |
| ISSN: | 0360-5442 |
| DOI: | 10.1016/j.energy.2017.04.111 |
| Popis: | The project reported in this paper used CFD as a tool to investigate the effect of multi-pass on the shell side heat transfer of a heat exchanger system. The heat exchanger system is equipped with six vertical thermosyphons transferring thermal energy from a heat source (air) to a heat sink (water). The CFD model has been experimentally validated. The two-phase change processes inside the thermosyphons were not modelled during the simulation. Instead, the thermosyphons were treated as solid rods with a constant thermal conductivity, which was calculated theoretically by applying the thermal resistance analogy with the aid of convection, boiling and condensation correlations found in the literature. The heat source consists of multiple air passes on the evaporator section of the thermosyphons and two water passes on the condenser section. Three different arrangements on the evaporator section were investigated with one, two or three shell passes and the thermal performance compared for the three configurations. The investigation was performed at various inlet conditions: a range of air inlet temperatures (100, 150, 200 and 250 °C) and mass flow rates (0.05, 0.08, 0.11 and 0.14 kg/s). The water inlet conditions were kept constant (a temperature of 15 °C and a mass flow rate of 0.08 kg/s). The overall rate of heat transfer was obtained by both CFD and a theoretical model, and the results lay within 15% of the experimental data. The numerical predictions demonstrated that the k − e Realizable turbulence model is a reliable tool for predicting heat transfer and fluid flow in such heat exchangers. |
| Databáze: | OpenAIRE |
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