Thermo-Hydraulic Performance Optimization of Intrusion-Type Curved Fins in Tube-Bank Heat Exchangers Using Response Surface Methodology

Year 2026, Volume: 14 Issue: 2 , 551 - 566 , 19.04.2026

Orhan Yalçınkaya

https://doi.org/10.29130/dubited.1860015

https://izlik.org/JA52AT63NE

Abstract

Flow separation and wake formation around circular tubes are among the primary causes of pressure losses and limited heat transfer performance in tube-bank heat exchangers (TBHEs). In this study, the thermo-hydraulic performance of a staggered circular tube-bank heat exchanger enhanced with a novel Inward Curved Ring-Winglet (ICRW) configuration was numerically investigated. Unlike conventional external fins that primarily increase surface area, the proposed intrusion-type design modified the core flow by partially penetrating into the channel region, promoting longitudinal vortex formation while suppressing wake recirculation. A three-dimensional steady-state CFD framework was developed in ANSYS Fluent using the RNG k–ε turbulence model to analyze airflow and heat transfer characteristics. The effects of four geometric parameters, namely winglet length (L), winglet gap (G), inclination angle (θ), and channel height (H), together with the Reynolds number (Re), were systematically examined using Response Surface Methodology (RSM). A Central Composite Design–based RSM framework was employed to construct surrogate models and identify the optimal design by maximizing the thermo-hydraulic performance factor (TPF). The performance evaluation was based on the TPF, which accounts for both Colburn j-factor and friction factor. The investigated parameter ranges were L = 12.5–22.5 mm, G = 0.75–2.25 mm, θ = 3.75°–15°, H = 3.125–12.5 mm, and Re = 1100–11500. The RSM analysis identified an optimal configuration at L = 22.105 mm, G = 2.10 mm, θ = 5.12°, and H = 3.14 mm, for which the maximum TPF of 1.53 was achieved at Re = 11239. Compared to the baseline tube-bank configuration, the optimized ICRW design significantly enhances heat transfer while maintaining acceptable pressure losses. Flow visualization results indicate that the improvement is mainly attributed to intensified longitudinal vortex structures and effective disruption of thermal boundary layers. The results demonstrate that intrusion-type ICRW fins provide a compact and effective passive enhancement strategy for high-performance air-side TBHE applications.

Keywords

Tube-bank heat exchanger , intrusion-type fin , CFD , Response surface method

Ethical Statement

This study does not involve human or animal participants. All procedures followed scientific and ethical principles, and all referenced studies are appropriately cited.

Supporting Institution

This research received no external funding.

Thanks

The author does not wish to acknowledge any individual or institution.

Response Surface Methodology Kullanılarak Boru Demeti Isı Değiştiricilerinde İçe Doğru Kıvrımlı Kanatçıkların Termo-Hidrolik Performans Optimizasyonu

https://izlik.org/JA52AT63NE

Abstract

Bu çalışmada, içe doğru kıvrımlı halka-kanatçık (Inward Curved Ring-Winglet, ICRW) konfigürasyonu ile geliştirilmiş dairesel ve şaşırtmalı bir boru demeti ısı değiştiricisinin termo-hidrolik performansı sayısal olarak incelenmiştir. Yüzey alanını artırmaya odaklanan geleneksel dışa doğru büyüyen kanatçık tasarımlarının aksine, önerilen bu içe doğru uzanan (intrusion-type) yapı, akış kanalının çekirdek bölgesine kısmen nüfuz ederek ana akışı doğrudan değiştirmekte; boyuna girdap oluşumunu teşvik ederken iz bölgesi geri dolaşımını baskılamaktadır. Hava akışı ve ısı transferi özelliklerini analiz etmek amacıyla, RNG k–ε türbülans modeli kullanılarak ANSYS Fluent ortamında üç boyutlu, kararlı durumlu bir HAD çerçevesi oluşturulmuştur. Kanatçık uzunluğu (L), kanatçık aralığı (G), eğim açısı (θ) ve kanal yüksekliği (H) olmak üzere dört temel geometrik parametrenin yanı sıra Reynolds sayısının (Re) etkileri, Yanıt Yüzey Yöntemi (Response Surface Methodology, RSM) kullanılarak sistematik biçimde değerlendirilmiştir. Performans değerlendirmesi, Colburn j faktörü ile sürtünme faktörünü birlikte dikkate alan termo-hidrolik performans faktörü (TPF) esas alınarak gerçekleştirilmiştir. İncelenen parametre aralıkları L = 12.5–22.5 mm, G = 0.75–2.25 mm, θ = 3.75°–15°, H = 3.125–12.5 mm ve Re = 1100–11500 olarak belirlenmiştir. RSM analizi sonucunda, L = 22.105 mm, G = 2.10 mm, θ = 5.12° ve H = 3.14 mm geometrik ölçülerinde, Re = 11239 için maksimum TPF değeri 1.53 olarak elde edilmiştir. Temel boru demeti konfigürasyonu ile karşılaştırıldığında, optimize edilmiş ICRW tasarımı ısı transferini belirgin biçimde artırırken kabul edilebilir basınç kayıplarını korumaktadır. Akış görselleştirme sonuçları, performans iyileşmesinin temel olarak güçlenen boyuna girdap yapıları ve termal sınır tabakasının etkin biçimde bozulmasından kaynaklandığını göstermektedir. Elde edilen bulgular, içe doğru uzanan ICRW kanatçıklarının yüksek performanslı boru demeti ısı değiştiricileri için kompakt ve etkili bir pasif iyileştirme stratejisi sunduğunu ortaya koymaktadır.

Keywords

Boru demetli ısı değiştirici , içe doğru kanatçık , HAD , yanıt yüzey yöntemi , pasif ısı transferi artırımı

Ethical Statement

Bu çalışma insan veya hayvan katılımcılar içermemektedir. Tüm prosedürler bilimsel ve etik ilkelere uygun olarak yürütülmüş olup, atıf yapılan tüm çalışmalar uygun şekilde kaynaklandırılmıştır.

Supporting Institution

Bu araştırma herhangi bir dış fon almamıştır.

Thanks

Yazar, herhangi bir kişi veya kuruma teşekkür etmek istememektedir.

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