3D Computational Analysis of Thermal and Hydraulic Performance of Louvered Fin Heat Exchanger With Variable Louver Angle and Louver Pitch

Author(s):  
Abdulkerim Okbaz ◽  
Ali Pınarbaşı ◽  
Ali Bahadır Olcay

In the present study, 3-D numerical simulations on heat and fluid flow characteristics of double-row multi-louvered fins heat exchanger are carried out. The heat transfer improvement and the corresponding pressure drop amounts were investigated depending on louver angles in the range of 20° ≤θ≤ 30°, louver pitches of Lp = 2,7mm, 3,5mm and 3,8mm and frontal velocities of Uin between 1.22 m/s and 3 m/s. The results are reported in terms of Colburn j-factor, Fanning friction factor f and area goodness factor j/f based on louver angle, louver pitch and Reynolds number. To understand local behavior of flow around louvered fins and heat exchanger tubes, flow visualization results of velocity vectors and stream-lines with temperature counters are presented. It is investigated that increasing louver angle enhances convective heat transfer while hydraulic performance decreases due to increased pressure drop. The flow noticeably behaves louver directed for all louver angles The flow can easily travel between different fins. This case study has been done to design and manufacture an industrial louver fin heat exchanger.

2000 ◽  
Vol 122 (3) ◽  
pp. 572-578 ◽  
Author(s):  
S. Y. Kim ◽  
J. W. Paek ◽  
B. H. Kang

The present experimental study investigates the impact of porous fins on the pressure drop and heat transfer characteristics in plate-fin heat exchangers. Systematic experiments have been carried out in a simplified model of a plate-porous fin heat exchanger at a controlled test environment. The porous fins are made of 6101 aluminum-alloy foam materials with different permeabilities and porosities. Comparison of performance between the porous fins and the conventional louvered fins has been made. The experimental results indicate that friction and heat transfer rate are significantly affected by permeability as well as porosity of the porous fin. The porous fins used in the present study show similar thermal performance to the conventional louvered fin. However, the louvered fin shows a little better performance in terms of pressure drop. For compactness of the heat exchanger, the porous fins with high pore density and low porosity are preferable. Useful correlations for the friction factor and the modified j-factor are also given for the design of a plate-porous fin heat exchanger. [S0022-1481(00)01103-8]


Author(s):  
Rong Yu ◽  
Andrew D. Sommers ◽  
Nicole C. Okamoto ◽  
Koushik Upadhyayula

In this study, we have explored the effectiveness of heat exchangers constructed using anisotropic, micro-patterned aluminum fins to more completely drain the condensate that forms on the heat transfer surface during normal operation with the aim of improving the thermal-hydraulic performance of the heat exchanger. This study presents and critically evaluates the efficacy of full-scale heat exchangers constructed from these micro-grooved surfaces by measuring dry/wet air-side pressure drop and dry/wet air-side heat transfer data. The new fin surface design was shown to decrease the core pressure drop of the heat exchanger during wet operation from 9.3% to 52.7%. Furthermore, these prototype fin surfaces were shown to have a negligible effect on the heat transfer coefficient under both dry and wet conditions while at the same time reducing the wet airside pressure drop thereby decreasing fan power consumption. That is to say, this novel fin surface design has shown the ability, through improved condensate management, to enhance the thermal-hydraulic performance of plain-fin-and-tube heat exchangers used in air-conditioning applications. This paper also presents data pertaining to the durability of the alkyl silane coating.


Author(s):  
M. Sabari ◽  
D. Channankiah ◽  
D. Shivalingappa

Heat exchanger plays a major role in almost all mechanical industries. Enhancement of heat transfer surface plays major role in numerous applications such as in heat exchangers, refrigeration and air conditioning systems etc. This paper examines the fluid flow and heat exchange on the air side of a multi-row fin-and-tube heat exchanger. A brief comparison is given between fin-and-tube heat exchanger attributes with louvered fins in a wider range of operating conditions defined by inlet air velocities. The brief representation on the calculated data for the louvered heat exchanger shows better heat transfer characteristics with a slightly higher pressure drop. The CFD procedure is validated by comparing the numerical simulation results with different inlet air velocities. Best combination of higher heat transfer and minimum pressure drop are occurred in inlet air velocity of 2.5 m/s.


Author(s):  
Sunil Mehendale

Microchannel evaporators are being increasingly considered for application in residential and commercial cooling and heat pump applications. This work analyzes the principles of refrigerant circuiting design in refrigerant-to-air heat exchangers using an element-by-element model developed for a microchannel evaporator. Geometric parameters such as microchannel tube depth, tube height, and port size, louvered fin density, louver angle, louver height, louver pitch, and fin height, as well as the air side face velocity, the refrigerant pressure-drop and heat transfer as a function of refrigerant mass flux are considered in the analysis. The model was first validated using data available in the open literature, thus providing a high level of confidence in the predictive ability of the model. Starting with a given microchannel tube and louvered fin geometry and a fixed number of tubes (and fins), the thermal performance of the heat exchanger was simulated over a wide range of two pass circuit configurations and tube lengths. It was found that the heat transfer versus pressure-drop trade-off provides an optimum relationship between the fraction of tubes in the first pass and the heat exchanger length. The sensitivity of the evaporator cooling capacity to the percentage of tubes in the first pass was also explored.


2015 ◽  
Vol 787 ◽  
pp. 72-76 ◽  
Author(s):  
V. Naveen Prabhu ◽  
M. Suresh

Nanofluids are fluids containing nanometer-sized particles of metals, oxides, carbides, nitrides, or nanotubes. They exhibit enhanced thermal performance when used in a heat exchanger as heat transfer fluids. Alumina (Al2O3) is the most commonly used nanoparticle due to its enhanced thermal conductivity. The work presented here, deals with numerical simulations performed in a tube-in-tube heat exchanger to study and compare flow characteristics and thermal performance of a tube-in-tube heat exchanger using water and Al2O3/water nanofluid. A local element-by-element analysis utilizing e-NTU method is employed for simulating the heat exchanger. Profiles of hot and cooling fluid temperatures, pressure drop, heat transfer rate along the length of the heat exchanger are studied. Results show that heat exchanger with nanofluid gives improved heat transfer rate when compared with water. However, the pressure drop is more, which puts a limit on the operating conditions.


2021 ◽  
Author(s):  
Syaiful ◽  
M. Kurnia Lutfi

The high thermal resistance of the airside of the compact heat exchanger results in a low heat transfer rate. Vortex generator (VG) is one of the effective passive methods to increase convection heat transfer by generating longitudinal vortex (LV), which results in an increase in fluid mixing. Therefore, this study aims to analyze the convection heat transfer characteristics and the pressure drop of airflow in a rectangular channel in the presence of a concave rectangular winglet VG on a heated plate. Numerical calculations were performed on rectangular winglet pairs vortex generators (RWP VGs) and concave rectangular winglet pairs vortex generators (CRWP VGs) with a 45° angle of attack and one, two, and three pairs of VGs with and without holes. The simulation results show that the decrease in the value of convection heat transfer coefficient and pressure drop on CRWP with three perforated VG configuration is 4.63% and 3.28%, respectively, of the three pairs of CRWP VG without holes at an airflow velocity of 2 m/s.


2018 ◽  
Vol 172 ◽  
pp. 02003
Author(s):  
R Badgujar Pankaj ◽  
S Rangarajan ◽  
S. R Nagaraja

The objective of the present paper is to propose an analytical model for calculating performance parameter of a radiator having rectangular tube with louvered fins. The theoretical effectiveness, heat transfer rate, outlet temperatures of both air and coolant are determined using effectiveness-NTU method. The coolant and air side pressure drop is also calculated. The proposed procedure is validated with experimetal results available in the literature and the GT model. It is found that the maximum deviation in the heat transfer rate calculated from proposed model is 10.97%, the coolant and air outlet temperatures is 2.75% and variation in pressure drop is about 3.29%.


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