scholarly journals Numerical and experimental analysis of a tube-and-fin cross-flow heat exchanger with a controlled non-uniform inflow of gas

2021 ◽  
Vol 323 ◽  
pp. 00005
Author(s):  
Tomasz Bury ◽  
Małgorzata Hanuszkiewicz-Drapała
Keyword(s):  
Heat Exchanger ◽  
Water Temperature ◽  
Experimental Test ◽  
Experimental Analysis ◽  
Cross Flow ◽  
Ansys Fluent ◽  
Flow Rates ◽  
Air Inlet ◽  
Flow Heat ◽  
The Impact

The paper presents results of numerical and experimental analyses of a fin-and-tube air-water heat exchanger. The analysed device is a one-row heat exchanger with finned elliptical tubes. The aim of the analyses is to investigate the impact of a controlled non-uniform inflow of air on the heat exchanger performance. The heat exchanger was modelled numerically using the ANSYS Fluent program. The developed model was applied to simulate the heat exchanger operation in the conditions of the uniform inflow of air. Cases of an uncontrolled non-uniform inflow of gas were investigated experimentally, using a purpose-designed test station. On the experimental test station the effect of a controlled non-uniform air inflow was also achieved by placing appropriately shaped inserts in the air inlet duct, directing the air partially to the region of the water inlet header. By controlling the gas inflow, it was possible to significantly enhance the heat exchanger performance. The results of the multivariate numerical analyses conducted for the adopted parameters of the mediums (air and water volumetric flow rates and water temperature) show that the heat exchanger performance can be improved by up to almost 5% compared to a variant with a natural non-uniform air inflow taking place in the exchanger under consideration.

Analysis of Flow Mal-Distribution in a Cross-Flow Heat Exchanger

2014 ◽  
Vol 592-594 ◽  
pp. 1428-1432 ◽  
Author(s):  
Krishna P. Mohan ◽  
Shekar M. Santosh ◽  
M. Ramakanth ◽  
M.R. Thansekhar ◽  
M. Venkatesan
Keyword(s):  
Heat Exchanger ◽  
Pressure Drop ◽  
Cross Flow ◽  
Flow Distribution ◽  
Ansys Fluent ◽  
Commercial Code ◽  
Uniform Flow Distribution ◽  
Flow Heat ◽  
Channel Assembly ◽  
Uniform Fluid

Flow mal-distribution is defined as the non-uniform fluid flow distribution among the parallel channels having a common header. Flow mal-distribution is present in every header channel assembly. This mal-distribution has a significant effect on the performance of the heat exchanger by increasing the pressure drop and affecting the heat transfer characteristics. However, in designing a heat exchanger, a uniform flow distribution in each channel is assumed. The present work attempts to reduce the flow mal-distribution in a cross flow heat exchanger. A numerical analysis is done using a commercial code ANSYS FLUENT 3D and the results are validated experimentally. A parametric study is done by changing the size of the channels within the heat exchanger so as to reduce the flow mal-distribution. The effect of varying channel size on flow mal-distribution and pressure drop across the heat exchanger is studied and a geometry with reduced flow mal-distribution is found.

Calculation of Transients in a Cross-Flow Heat Exchanger

1959 ◽  
Vol 81 (1) ◽  
pp. 61-67 ◽  
Author(s):  
G. M. Dusinberre
Keyword(s):  
Heat Exchanger ◽  
Numerical Methods ◽  
Gas Turbine ◽  
Digital Computer ◽  
Computer Programming ◽  
Cross Flow ◽  
Flow Rates ◽  
Flow Heat

This paper shows how transient temperatures in a cross-flow heat exchanger may be calculated by numerical methods. Digital computer programming is considered. A gas-turbine regenerator is used as an example. In particular, methods are developed which are useful when the flow rates vary, as in the starting transient.

scholarly journals Dynamics of Cross-Flow Heat Exchanger Tubes With Multiple Loose Supports

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Anwar Sadath ◽  
Harish N. Dixit ◽  
C. P. Vyasarayani
Keyword(s):  
Heat Exchanger ◽  
Flow Velocity ◽  
Galerkin Approximation ◽  
Cross Flow ◽  
Beam Equation ◽  
Critical Flow Velocity ◽  
Flow Heat ◽  
Delay Differential ◽  
The Impact ◽  
Loose Support

Dynamics of cross-flow heat exchanger tubes with two loose supports has been studied. An analytical model of a cantilever beam that includes time-delayed displacement term along with two restrained spring forces has been used to model the flexible tube. The model consists of one loose support placed at the free end of the tube and the other at the midspan of the tube. The critical fluid flow velocity at which the Hopf bifurcation occurs has been obtained after solving a free vibration problem. The beam equation is discretized to five second-order delay differential equations (DDEs) using Galerkin approximation and solved numerically. It has been found that for flow velocity less than the critical flow velocity, the system shows a positive damping leading to a stable response. Beyond the critical velocity, the system becomes unstable, but a further increase in the velocity leads to the formation of a positive damping which stabilizes the system at an amplified oscillatory state. For a sufficiently high flow velocity, the tube impacts on the loose supports and generates complex and chaotic vibrations. The impact loading on the loose support is modeled either as a cubic spring or a trilinear spring. The effect of spring constants and free-gap of the loose support on the dynamics of the tube has been studied.

scholarly journals Performance Analysis of a Countercurrent Flow Heat Exchanger Placed on the Truck Compartment Roof

2012 ◽  
Vol 4 (4) ◽  
Author(s):  
Wamei Lin ◽  
Jinliang Yuan ◽  
Bengt Sundén
Keyword(s):  
Heat Exchanger ◽  
Thermal Performance ◽  
Cross Flow ◽  
Countercurrent Flow ◽  
Position Change ◽  
Power Requirement ◽  
Ansys Fluent ◽  
Pin Fin ◽  
Flow Heat ◽  
The Cross

Due to the increasing power requirement and the limited available space in vehicles, placing the heat exchanger at the roof or the underbody of vehicles might increase the possibility to handle the cooling requirement. A new configuration of the heat exchanger has to be developed to accommodate with the position change. In this paper, a countercurrent heat exchanger is developed for position on the roof of the vehicle compartment. In order to find an appropriate configuration of fins with high thermal performance on the air side, the computational fluid dynamics approach is applied for a comparative study among louver fin, wavy fin, and pin fin by using ANSYS FLUENT software. It is found that the louver fin performs high thermal performance and low pressure drop. Thus, the louver fin is chosen to be the configuration of the countercurrent flow heat exchanger. It is also found that the countercurrent flow heat exchanger presents higher heat transfer coefficient than the cross flow heat exchanger. Furthermore, the overall size and the air pumping power of the countercurrent flow heat exchanger are lower than those in the cross flow heat exchanger. Several suggestions and recommendations are highlighted.

scholarly journals Performance Analysis of a Countercurrent Flow Heat Exchanger Placed on the Truck Compartment Roof

2011 ◽  
Author(s):  
Wamei Lin ◽  
Jinliang Yuan ◽  
Bengt Sunde´n
Keyword(s):  
Heat Exchanger ◽  
Thermal Performance ◽  
Cross Flow ◽  
Countercurrent Flow ◽  
Position Change ◽  
Power Requirement ◽  
Ansys Fluent ◽  
Pin Fin ◽  
Fluent Software ◽  
Flow Heat

Due to the increasing power requirement and the limited available space in vehicles, placing the heat exchanger at the roof or the underbody of vehicles might increase the possibility to handle the cooling requirement. A new configuration of the heat exchanger has to be developed to accommodate with the position change. In this paper, a countercurrent heat exchanger is developed for position on the roof of the vehicle compartment. In order to find an appropriate configuration of fins with high thermal performance on the air side, the CFD (computational fluid dynamics) approach is applied for a comparative study among louver fin, wavy fin, and pin fin by using ANSYS FLUENT software. It is found that the louver fin has high thermal performance and low pressure drop. Thus, the louver fin is chosen to be the configuration of the countercurrent heat exchanger, which presents higher heat transfer coefficient than a cross flow heat exchanger. For a specific case, the overall size and the air pumping power of the countercurrent flow heat exchanger is lower than that one for a cross flow heat exchanger. Several suggestions and recommendations are highlighted.

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