Numerical study on heat transfer enhancement of circular tube bank fin heat exchanger with interrupted annular groove fin

2014 ◽  
Vol 73 (2) ◽  
pp. 1465-1476 ◽  
Author(s):  
Zhi-Min Lin ◽  
Liang-Bi Wang ◽  
Yong-Heng Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Circular Tube ◽  
Numerical Study ◽  
Transfer Enhancement ◽  
Tube Bank

Heat Transfer Characteristics of a Circular Channel Inserted Metallic Wire With High Porosity

2010 ◽  
Author(s):  
Mitsutoshi Tendo ◽  
Tetsuaki Takeda
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Circular Tube ◽  
Copper Wire ◽  
Heat Transfer Surface ◽  
High Porosity ◽  
Transfer Enhancement ◽  
Heat Transfer Characteristics ◽  
Metallic Wire

There are several methods for heat transfer enhancement. For example, there are attaching various fins on the heat transfer surface, processing the surface roughly, inserting twisted tape, and so on. These methods increase heat transfer coefficient or area by manufacturing of the heat transfer surface. However, it has to take into consideration the deterioration of the structure strength by attaching the fins on the tube surface with the design of the heat exchanger. The objective of this study is to clarify characteristics of heat transfer and pressure drop in the channel inserted metallic wire with high porosity. A heat transfer experiment has been performed using a horizontal circular tube to obtain the heat transfer characteristics in the channel inserted copper wire. This paper describes the heat transfer and flow characteristics of a heat exchanger tube filled with a high porous material. Fine copper wire (diameter: 0.5 mm) was inserted in a circular tube dominated by thermal conduction and forced convection. Working fluid was air. Hydraulic equivalent diameter was cited as the characteristic length in Nusselt number and Reynolds number. From the results obtained in this experiment, it was found that an amount of heat transfer in the tube with the copper wire was larger than that without one. An effectiveness of heat transfer enhancement increased with the temperature of the heated wall. The amount of heat transfer in the circular tube inserted copper wire, which has 0.993–0.998 of porosity, increased about 15% comparing with the tube having a smooth wall surface under the condition of the constant heat flux and lower than 170°C of the wall temperature.

Numerical Investigation of Heat Transfer Enhancement Using Hybrid Vortex Generator Arrays in Fin-and-Tube Heat Exchangers

2016 ◽  
Vol 8 (3) ◽  
Author(s):  
Shubham Agarwal ◽  
R. P. Sharma
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Heat Exchangers ◽  
Numerical Study ◽  
Vortex Generator ◽  
Roll Angle ◽  
Transfer Enhancement ◽  
Maximum Heat ◽  
Hybrid Configuration

This is a novel study for assessing the heat transfer enhancement in a multi-row inline-tube heat exchanger using hybrid vortex generator (VG) arrays, i.e., rectangular winglet pairs (RWPs) with different geometrical configurations installed in coherence for enhanced heat transfer. The three-dimensional numerical study uses a full scale seven-tube inline heat exchanger model. The effect of roll of rectangular winglet VG on heat transfer enhancement is analyzed and optimized roll angle is determined for maximum heat transfer enhancement. Four different configurations are analyzed and compared in this regard: (a) single RWP (no roll); (b) 3RWP-inline array(alternating tube row with no roll of VGs); (c) single RWP (with optimized roll angle VGs); and (d) 3RWP-inline array(alternating tube row with all VGs having optimized roll angle). It was found that the inward roll of VGs increased the heat transfer from the immediately downstream tube but reduced heat transfer enhancement capability of other VG pairs downstream. Further, four different hybrid configurations of VGs were analyzed and the optimum configuration was obtained. For the optimized hybrid configuration at Re = 670, RWP with optimized roll angle increased heat transfer by 17.5% from the tube it was installed on and by 42% from the immediately downstream tube. Increase in j/ƒ of 36.7% is obtained by use of hybrid VGs in the optimized hybrid configuration. The deductions from the current study are supposed to well enhance the performance of heat exchangers with different design configurations.

A Numerical Study of Flow and Heat Transfer Enhancement Using an Array of Delta-Winglet Vortex Generators in a Fin-and-Tube Heat Exchanger

2006 ◽  
Vol 129 (9) ◽  
pp. 1156-1167 ◽  
Author(s):  
A. Joardar ◽  
A. M. Jacobi
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Numerical Study ◽  
Flow Behavior ◽  
Vortex Generators ◽  
Computational Domain ◽  
Transfer Enhancement ◽  
Local Flow ◽  
Tube Heat Exchanger

This work is aimed at assessing the potential of winglet-type vortex generator (VG) “arrays” for multirow inline-tube heat exchangers with an emphasis on providing fundamental understanding of the relation between local flow behavior and heat transfer enhancement mechanisms. Three different winglet configurations in common-flow-up arrangement are analyzed in the seven-row compact fin-and-tube heat exchanger: (a) single–VG pair; (b) a 3VG-inline array (alternating tube row); and (c) a 3VG-staggered array. The numerical study involves three-dimensional time-dependent modeling of unsteady laminar flow (330⩽Re⩽850) and conjugate heat transfer in the computational domain, which is set up to model the entire fin length in the air flow direction. It was found that the impingement of winglet redirected flow on the downstream tube is an important heat transfer augmentation mechanism for the common-flow-up arrangement of vortex generators in the inline-tube geometry. At Re=850 with a constant tube-wall temperature, the 3VG-inline-array configuration achieves enhancements up to 32% in total heat flux and 74% in j factor over the baseline case, with an associated pressure-drop increase of about 41%. The numerical results for the integral heat transfer quantities agree well with the available experimental measurements.

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