Multi-objective optimization of axially flat finned cam-shaped and elliptical tube banks based on entropy generation and thermal hydraulic performance

Year 2025, Volume: 16 Issue: 4, 1059 - 1066, 30.12.2025

Mehmet Özkarakoç , Muhammet Nasıf Kuru

https://doi.org/10.24012/dumf.1809125

Abstract

The use of different tube geometries in tube bank heat exchangers has a significant impact on thermal hydraulic performance and entropy generation. This study determined the geometric dimensions and operating conditions of a tube bank with in-line arrangement of cam-shaped and elliptical tubes with axially fins using a numerical optimization method. In order to maintain equal heat transfer surface areas, equivalent diameters (D_e=12.7 mm) were assumed for the tube geometries (cam and elliptical). The longitudinal (N_L ) and transversal (N_T ) configurations consist of four tubes. Diagrams of the multi-objective optimization workflow were established for two different tube geometries. The objective functions selected here were the reduction of entropy generation S_gen and the increase in thermal hydraulic performance (THP). The geometric optimization variables were the transversal tube spacing (y_interval ), longitudinal tube spacing (x_interval ) and longitudinal fin length (L_fin ), which varied within the ranges D_e⁄4 and D_e, respectively. The average velocity at the channel inlet V_in was used as the optimization variable for the operating condition and varies within the range 1 m/s

Keywords

Tube bank , axially flat fin , cam-shaped tube , elliptical tube , multi-objective optimization

Entropi üretimi ve termal hidrolik performansa dayalı eksenel olarak düz kanatlı kam şekilli ve eliptik boru demetlerinin çok amaçlı optimizasyonu

Abstract

Boru demeti ısı değiştiricilerde farklı boru geometrilerinin kullanımı, ısıl hidrolik performans ve entropi üretimi üzerinde önemli bir etkiye sahiptir. Bu çalışmada, sayısal bir optimizasyon yöntemi kullanılarak; düzgün sıralı dizilime sahip eksenel düz kanatlı, kam şekilli ve eliptik borulu boru demetinin geometrik boyutları ve çalışma koşulları belirlenmiştir. Eşit ısı transfer yüzey alanları sağlamak amacıyla, boru geometrileri (kam ve eliptik) için eşdeğer çaplar (D_e=12,7 mm) kabul edilmiştir. Konfigürasyonlar, boyuna (N_L ) ve enine (N_T ) dört borudan oluşmaktadır. İki farklı boru geometrisi için çok amaçlı optimizasyon iş akış şemaları oluşturulmuştur. Burada seçilen amaç fonksiyonları, entropi üretiminin (S_gen ) azaltılması ve ısıl hidrolik performansın (THP) artırılmasıdır. Geometrik optimizasyon değişkenleri; sırasıyla D_e⁄4 ve D_e arasında değişen enine borular arası boşluk (y_interval ), boyuna borular arası boşluk (x_interval ) ve boyuna kanat uzunluğudur (L_fin ). Çalışma koşulu için optimizasyon değişkeni olarak kanal girişindeki ortalama hız (V_in ) kullanılmış ve (1 m⁄s≤V_in≤6 m⁄s) aralığında değiştirilmiştir. Sonuç olarak, incelenen optimizasyon problemleri için elde edilen Pareto tasarımlar değerlendirildiğinde; elde edilen en düşük entropi üretim değerleri kam şekilli boru demeti için daha düşükken (5.05%), elde edilen en yüksek ısıl-hidrolik performans değerleri eliptik boru demeti için daha yüksektir (1.66%).

Keywords

Boru demeti , Eksenel düz kanat , Kama şekilli boru , Eliptik boru , Çok amaçlı optimizasyon

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