Computer-aided engineering analysis for the performance augmentation of a fin-tube heat exchanger using vortex generator (original) (raw)
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Applied Thermal Engineering, 2013
In present work, heat transfer enhancement and pressure loss penalty for fin-and-tube heat exchangers with rectangular winglet pairs (RWPs) were numerically investigated in a relatively low Reynolds number flow. The purpose of this study was to explore the fundamental mechanism between the local flow structure and the heat transfer augmentation. The RWPs were placed with a special orientation for the purpose of enhancement of heat transfer. The numerical study involved three-dimensional flow and conjugate heat transfer in the computational domain, which was set up to model the entire flow channel in the air flow direction. The effects of attack angle of RWPs, row-number of RWPs and placement of RWPs on the heat transfer characteristics and flow structure were examined in detail. It was observed that the longitudinal vortices caused by RWPs and the impingement of RWPs-directed flow on the downstream tube were important reasons of heat transfer enhancement for fin-and-tube heat exchangers with RWPs. It was interesting to find that the pressure loss penalty of the fin-and-tube heat exchangers with RWPs can be reduced by altering the placement of the same number of RWPs from inline array to staggered array without reducing the heat transfer enhancement. The results showed that the rectangular winglet pairs (RWPs) can significantly improve the heat transfer performance of the finand-tube heat exchangers with a moderate pressure loss penalty.
2017
Vortex generator is considered as an effective device for augmentation of the thermal-hydraulic performance of a heat exchanger. The aim of present study is to examine the influence of vortex generators on a double fin and tube heat exchanger performance. Vortex generator of rectangular winglet type is chosen and investigated at different angles of attack 0◦, −10◦ and −20◦ with the flow direction. Three-dimensional numerical model is developed and simulations are performed for a Reynolds number range 5000 ≤ Re ≤ 11000 taking conjugate heat transfer into account. The heat transfer and pressure loss characteristics are determined and analyzed for an in-line configuration of a fin and tube heat exchanger. In order to evaluate the enhancement in the performance on an equitable basis, the heat exchanger with plain fin surface is considered as a reference design. Results show that the angle of attack of a vortex generator has a significant impact on the volume goodness factor, and enhance...
Efficiency Enhancement of Fin Tube Heat Exchanger Using New Winglet Vortex Generator
High performance requirement for thermal systems in engineering applications have led researchers to search for enhancement techniques that will increase heat transfer rates in systems. Longitudinal vortex generation is a common technique for enhancing heat transfer performance. It can be achieved by employing small flow manipulators, known as vortex generator (VGs), which are placed on the heat transfer surface. The vortex generators (VGs) can generate longitudinal and horseshoe vortices. These vortices strongly disturb the flow structure and have significant influence on the velocity and temperature fields, which in turn cause heat transfer enhancement. The main aim of this study is The effects of the different configurations of the vortex generator types is used in the CFD simulation to obtain the accurate results the geometrical optimization is used in the project using the shapes like Gothic, Rectangular, Triangular, Parabolic, Ogive to determine which shape gives the optimum heat transfer in all the arrangement's standard boundary conditions is adopted to conclude the shape of the heat exchanger vortex generator.
Energy Procedia, 2014
In the present study, 3D computational analysis was performed to investigate heat transfer and pressure drop characteristics of flow in new Smooth Wavy Fin-and-Elliptical Tube (SWFET) heat exchanger model with new vortex generators. Performance results are presented in terms of non-dimensional parameters, friction factor f and Colburn j factor. Four new types of vortex generators were considered; rectangular trapezoidal winglet (RTW), angle rectangular winglet (ARW), curved angle rectangular winglet (CARW) and Wheeler wishbone (WW). Fluid flow and heat transfer are simulated and the results are compared. The SST k ω − turbulence model is used, with steady-state solvers to calculate pressure drop, flow and temperature fields. The influences of the geometrical factors of mounted vortex generators including attack angles of the winglets (15 ,30 , 45 ,60 VG α = and 75°) and width/length aspect ratio (0.5,1.0 w l =) of the Wheeler wishbones in enhancing the heat transfer performance of a smooth wavy fin heat exchanger with a three-row staggered elliptical tube bundle are investigated. The Reynolds number ranges from 500 to 3000 based on the hydraulic diameter. A parametric study on the winglet vortex generators indicated that for the small attack angle, CARW vortex generators gives better thermohydraulic performance under the present conditions.
Effect of a delta-winglet vortex pair on the performance of a tube–fin heat exchanger 2007
The experimental analysis of the effects of delta-winglet vortex generators on the performance of a fin and tube radiator is presented. The winglets were arranged in flow-up configuration, and placed directly upstream of the tube. This is a hitherto untested configuration, but is thought to have certain advantages. In addition to vortex generation the flow is guided onto the tube surface increasing the localised velocity gradients and Nusselt numbers in this region. The study includes dye visualisation and full scale heat transfer performance measurements. The results are compared to a standard louvre fin surface. It was found that the winglet surface had 87% of the heat transfer capacity but only 53% of the pressure drop of the louvre fin surface.
International Journal of Engineering Sciences & Research Technology, 2014
This review paper presents the work of various researchers on the heat transfer enhancement of fin tube heat exchanger. In this research author used different type of vortex generator like delta winglet, rectangular winglet, curved trapezoidal winglet pair. The vortex generator can be embedded in the plate fin and that too in a low cost with effect the original design and setup of the commonly used heat exchangers. The various design modifications which are implemented and studied numerically and experimentally is been discussed in the paper
Effect of a delta-winglet vortex pair on the performance of a tube-fin heat exchanger
International Journal of Heat and Mass Transfer, 2007
The experimental analysis of the effects of delta-winglet vortex generators on the performance of a fin and tube radiator is presented. The winglets were arranged in flow-up configuration, and placed directly upstream of the tube. This is a hitherto untested configuration, but is thought to have certain advantages. In addition to vortex generation the flow is guided onto the tube surface increasing the localised velocity gradients and Nusselt numbers in this region. The study includes dye visualisation and full scale heat transfer performance measurements. The results are compared to a standard louvre fin surface. It was found that the winglet surface had 87% of the heat transfer capacity but only 53% of the pressure drop of the louvre fin surface.
CFD analysis of fin tube heat exchanger with a pair of delta winglet vortex generators
Among tubular heat exchangers, fin-tube types are the most widely used in refrigeration and air-conditioning equipment. Efforts to enhance the performance of these heat exchangers included variations in the fin shape from a plain fin to a slit and louver type. In the context of heat transfer augmentation, the performance of vortex generators has also been investigated. Delta winglet vortex generators have recently attracted research interest, partly due to experimental data showing that their addition to fin-tube heat exchangers considerably reduces pressure loss at heat transfer capacity of nearly the same level. The efficiency of the delta winglet vortex generators widely varies depending on their size and shape, as well as the locations where they are implemented. In this paper, the flow field around delta winglet vortex generators in a common flow up arrangement was analyzed in terms of flow characteristics and heat transfer using computational fluid dynamics methods. Flow mixing due to vortices and delayed separation due to acceleration influence the overall fin performance. The fin with delta winglet vortex generators exhibited a pressure loss lower than that of a plain fin, and the heat transfer performance was enhanced at high air velocity or Reynolds number.
Heat Transfer Performance of a Fin and Ovaltube Heat Exchanger with Delta Winglet Vortex Generators
In this thesis, thermal performance assessments, flow configurations and heat transfer characteristics in a fin-and-oval-tube heat exchanger with the delta winglet vortex generators are investigated analytically and compared with that of original model. Delta winglet vortex generators like V-ribs are placed on fin surfaces. The effects of varying Reynolds numbers on heat transfer, heat transfer coefficient and thermal performance are determined. The velocities for the input of CFD analysis are calculated from Reynolds number. 3D modeling of the fin-and-oval-tube heat exchanger without and with the delta winglet vortex generators is done in Creo 2.0. CFD and thermal analysis are done in Ansys. The heat transfer coefficient which is used as input for thermal analysis is taken from the results of CFD analysis.