The following report attempts to make up for the deficiencies of theoretical Reynolds comparison by using an approach based on redefined parameter groups – specifically meant for cross-flow air coolers and/or air-cooled condensers. It will allow to directly evaluate different fin tube systems based on their performance characteristics alone.
Fin tubes are core elements of air cooled heat exchangers in industrial cooling applications. Thermohydraulic performance of the cooling system defines the overall size of the equipment. Fin tube characteristics vary over a large range resulting from geometry, material or manufacturing process. As a general rule - the better the performance the smaller and more competitive the design will be. Consequently, manufacturers strive for thermohydraulic optimization of their product line. A key factor is the ability to properly compare different cooling devices.
Comparison methods have been a topic in the academic field over a long period of time. Methods proposed so far have been based on classical dimensionless parameters, especially Reynolds number. Apart from transport properties Reynolds numbers include a geometric parameter pertinent to the individual heat exchanger system. If geometry is varied Reynolds changes as well. This is one of the reasons why Reynolds based comparison methods - although theoretically sound – lack practical applicability.
Inhaltsverzeichnis (Table of Contents)
- Introduction
- Classical Form of Fin Tube Characteristics
- New Form of Fin Tube Characteristics
- Base Evaluation ….......
- General Evaluation
- Optimization Examples
- Summary..
Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)
This report aims to address the limitations of traditional Reynolds-based comparison methods for fin tube systems by introducing a new approach utilizing redefined parameter groups specifically tailored for cross-flow air coolers and condensers. The goal is to enable direct comparison of different fin tube systems based solely on their performance characteristics, thus facilitating optimization and selection processes.
- Comparison of different fin tube systems
- Optimization of thermohydraulic performance
- Redefined parameter groups for air coolers and condensers
- Face area concept for fin tube characteristics
- Limitations of classical dimensionless parameters
Zusammenfassung der Kapitel (Chapter Summaries)
- Introduction: This chapter provides an overview of atmospheric cooling systems and the diverse range of fin tube variations used in these systems. It highlights the limitations of general correlations due to the vast variety of fin tube geometries and emphasizes the need for a new approach to compare different systems effectively.
- Classical Form of Fin Tube Characteristics: This chapter discusses the conventional method of summarizing fin tube characteristics using dimensionless numbers, such as Reynolds number, heat transfer coefficient, and pressure drop coefficient. It explains the challenges associated with defining a universal hydraulic diameter for complex fin tube geometries, making Reynolds number less suitable for general comparisons.
- New Form of Fin Tube Characteristics: This chapter introduces a new approach based on a "black box" principle, where the face area velocity is used as the defining air speed, allowing for direct comparison of different fin tube systems. It defines the new pseudo Reynolds flow number (Ry), heat transfer (pseudo Nusselt) number (Ny), and pressure drop (pseudo Euler) number (Ey), which account for the complexities of fin tube geometries.
Schlüsselwörter (Keywords)
The key terms and concepts explored in this report include: fin tubes, thermohydraulic performance, comparison methods, Reynolds number, cross-flow air coolers, air-cooled condensers, redefined parameter groups, face area concept, pseudo Reynolds flow number (Ry), pseudo Nusselt number (Ny), pseudo Euler number (Ey).
- Quote paper
- Hans Georg Schrey (Author), 2017, Thermohydraulic Comparison of Fin Tubes, Munich, GRIN Verlag, https://www.grin.com/document/414394
