Numerical Study of 3d Thermal and Hydraulic Characteristics of Wavy Fin-and-Tube Heat Exchanger

Abstract

This numerical analysis presents the airside performance of a wavy fin-and-tube heat exchanger having 4 row configurations considering steady, incompressible and 3D flow using Commercial CFD Code ANSYS CFX 12.0. Results are presented in the form of friction factor (f), Colburn factor (j) and efficiency index (j/f). The numerical procedure has been validated by comparison with published numerical and experimental results and good agreement has been observed. A series of numerical calculations have been carried out in order to analyze the influence of various geometric characteristics on different fields as well as on the heat transfer and pressure drop and efficiency within a heat exchanger. The effects of longitudinal pitch (Ll), transverse pitch (Lt), Fin Pitch (Fp), wavy angle (Wa) and inlet flow angle (α) on wavy fin-and-tube heat exchanger are studied. Different inlet flow angles such as 0 , + 17.5˚, -17.5˚, +35˚ and -35˚ are employed normal to the face of the heat exchanger in order to investigate the performance of inlet flow angles. There is a strong correlation between the response of the flow efficiency, pressure drop and heat transfer performance to these parameters.

Plate Fin and Tube Heat Exchanger Modeling: Effects of Performance Parameters for Turbulent Flow Regime

“…The suitability of the k-ω turbulent model has been evaluated comparing other models with the turbulent model and considerable success has been achieved in predicting performance by using this model. The distinctiveness in flow comparisons between staggered and inline arrangements have been demonstrated previously (Bhuiyan et al, 2012a;Bhuiyan et al, 2012b). For the plain fin staggered configurations flow interruption takes place on both sides of the domain.…”

“…This model is widely used and is a tested turbulence model. A numerical study considering various turbulent models and their effectiveness in the transitional regime for similar geometries has been conducted recently (Bhuiyan et al, 2012a;Bhuiyan et al, 2012b). The suitability of the k-ω turbulent model has been evaluated comparing other models with the turbulent model and considerable success has been achieved in predicting performance by using this model.…”

“…As mentioned earlier, this study is based on the experimental work of (Menter, 1994) and is a continuation of the numerical work of (Bhuiyan et al, 2012a;Bhuiyan et al, 2011)and the geometry considered for the analysis are plain fin, with inline and staggered tube arrangements. The detailed geometric dimensions are given in Table 1.…”

“…Therefore the suitability of any particular turbulence model for the practical applications of the plate-fin heat exchanger is not addressed. This author studied the suitability of different turbulent models, the k-ɛ model, RNG k-ɛ model, and k-ɷ model and finally k-ɷ model was considered an appropriate choice for turbulent flow (Bhuiyan, Islam, & Amin, 2012a).This author has previously also investigated the flow characteristics for plain and wavy fin tube staggered and inline arrangements for laminar and transitional flow range (Bhuiyan et al, 2012a;Bhuiyan, Amin, & Islam, 2012b;Bhuiyan, Islam, & Amin, 2011). The effects of different geometric parameters such as longitudinal, pitch, transverse pitch, and fin pitch for plain fin, as well as wavy angle and wavy height for the wavy fin have also already been investigated, but all these studies were limited for laminar to the transitional range.…”

“…The effects of different geometric parameters such as longitudinal, pitch, transverse pitch, and fin pitch for plain fin, as well as wavy angle and wavy height for the wavy fin have also already been investigated, but all these studies were limited for laminar to the transitional range. In this study, the simulation results for plain fin, considering staggered arrangements for turbulent (2100 ≤ Re H ≤ 7000) flow range, will be investigated to determine their effect on the heat transfer and pressure drop performance based on the available experimental data of (Yuan, 2000)and as a continuation of the numerical work of the authors for laminar flow (Bhuiyan et al, 2011)and transitional flow (Bhuiyan et al, 2012a;Bhuiyan et al, 2012b). A detailed analysis of the effect of the geometrical parameters mentioned above will also be presented.…”