ESG-3 Critical Evaluation of Effects of Finned Tube Geometry Parameters and Survey of Data Sources

T. Rozenman and J. Taborek

A summary of published experimental data on finned tubes and a qualitative interpretation of these data is given in this report. The variety of shapes and sizes of finned tubes, as well as their arrangement in a bank, provides almost unlimited design configurations. This is reflected in the literature by the voluminous experimental data as well as theoretical analysis and discussions related to flow dynamics and heat transfer in banks of finned tubes. The literature publications vary widely both in scope and quality. The data range from ""design curves"" for a particular tube type arranged in a specific layout to a systematic study of the effects of fin and geometry types.

In the first part of the report, a discussion on the difficulties in the theoretical analysis of heat transfer in finned tubes is followed by a discussion on available information on single tubes. The important contribution of this part lies in the conclusion which states that single tube experiments cannot be used to predict the performance of a tube bank.

The second part of this report is a compilation of information on all the published experiments on banks of finned tubes. A review of the data sources, experimental methods and general reliability of the data is discussed.

The last part of the report is devoted to a systematic analysis of the effects of fin geometry and other design parameters on the performance of finned tube banks. The choice of a specific tube for a deign might be dictated by a variety of mechanical, thermal, and economical considerations. An optimal design can be made only if the effects of the finned tube variables on both heat transfer and pressure drop performance is considered as an integral problem. The following variables were critically analyzed based on the available literature sources.

  1. Comparison of data on inline and staggered arrangement.
  2. Effect of variations in the tube pitch and pitch angle on the performance of a tube bank.
  3. The tube bank performance with respect to the number of rows.
  4. Effect of fin height and fin spacing--the two most important variables of the finned tube geometry.
  5. Effect of fin thickness on the convection coefficient of a tube bank.
  6. Base tube diameter