An extensive analytical DOE-based dimensionless performance comparison of plain, wavy and louvered finned-tube heat exchangers.

Number: 2416

Author(s) : GIMENEZ F. R., CONCEIÇÃO S. T., RIBEIRO G. B.

Summary

In this study, three of the most traditional finned-tube heat exchanger configurations were numerically evaluated using an extensive range of air-side core design parameter combinations. The main objective is to understand the impact of each design parameter on the heat exchangers performance, to investigate the typical and optimal results of each heat exchanger concept, and to conduct a comparative analysis between them. The Chilton-Colburn j-factor analogy, the Fanning friction f-factor, and the ratio of 𝑗/𝑓 were chosen as the dimensionless performance indicators. Utilizing correlations numerically regressed from Wang et al.’s (1997, 1999, 2000) wind tunnel experiments, the plain, the wavy and the louvered finned-tube heat exchangers were analytically investigated. To guarantee the full exploration of the mean and the best performance of the heat exchangers cores, their design parameters were widely combined in a full-factorial Design of Experiments (DOE) evaluation. Depending on the number of design parameters of the heat exchanger type, an order of magnitude of 10,000 to 100,000 combinations were analyzed for each core configuration. The core design parameters were varied between dimension limits experimentally assessed by Wang et al. (1997, 1999, 2000). Python and Engineering Equation Solver (EES) scripts were employed to model the heat exchangers correlations, their heat transfer and discharge loss performance, and to determine all DOE combinations and post-processing. A sensitivity analysis was first conducted to indicate which heat exchangers’ design parameters contribute the most to the core performance increase. Afterwards, all heat exchangers combinations were plotted in j- to f-factor point cloud charts to compare their performance range between each other. Both indexes give a dimensionless approach of all core combination possibilities among the heat exchangers, resulting in a fairer comparison criterion within the proposed universe of combinations. Statistical filtering was also conducted to remove possible numerical outliers, delivering the performance boundaries for the plain, the wavy and the louvered finned-tube heat exchangers. Ultimately, the louvered heat exchanger exhibited the highest mean 𝑗/𝑓 factor of 0.3634, among all heat exchangers, followed by the wavy and the plain finned-tube core, with -44.0% and -52.4% less performance, respectively. Therefore, the extensive DOE study results, with the performance charts and indicators, corroborate with different past references showing a greater advantage of the louvered heat exchanger compared to the wavy and the plain configurations, which are both closer to each other. Additionally, among all DOE combinations, this study provides the highest performing design parameters setup for each heat exchanger type that delivers the greatest 𝑗/𝑓 factor results. The louver configuration achieved an optimal 𝑗/𝑓 of 3.2510, followed by the plain and the wavy concepts, which exhibited peak performance reductions of -40.9% and -86.1%, respectively.

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Details

  • Original title: An extensive analytical DOE-based dimensionless performance comparison of plain, wavy and louvered finned-tube heat exchangers.
  • Record ID : 30033135
  • Languages: English
  • Subject: Technology
  • Source: 2024 Purdue Conferences. 20th International Refrigeration and Air-Conditioning Conference at Purdue.
  • Publication date: 2024/07/17

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