Numerical Analysis on The Effect of Longitudinal and Transversal Pitch Ratio to The Flow and Heat Transfer Characteristic of Staggered Elliptical Tubes-Bank

摘要

Numerous studies have been conducted to improve the heat exchanger performance. Most of them dealt with the geometry of tube banks as the core of heat exchanger. Within some previous decades the research of non-circular tube banks received greater attention. Elliptic tube is one of the most promising alternative to construct better heat exchanger core. It is due to the aerodynamic profile characteristic of ellipse. This study is carried out to find out the characteristics of fluid flow and heat transfer across staggered elliptical tube banks. The aspect ratio of the tube is 2.5 whilst the banks consist of 3 x 5 tubes. The banks configures in 16 arrangement models in accordance with 4 variations of both Pt and Pl. Air flow of 300K and 4 m/s across the banks is modeled as ideal gas. The tube surface emits a uniform heat flux of 2000 W/m~2. The study is based on 2 dimension steady state model on Computational Fluid Dynamic commercial software. The study reveals that the lower PT value the higher pressure drop and Nusselt Number. Model A of both Pt and Pl= 0.9 gains the highest Nu of 45.13 and pressure drop of 93.15 Pa. On the contrary, model P of both Pt and PL= 1.25 obtains the lowest Nu of 37.8 and pressure drop of 32.46 Pa. It is also concluded that model P performs highest ratio of Nu to pressure drop.