A general and rapid method to evaluate the effect of flow maldistribution on the performance of heat exchangers

2021 ◽  
Vol 170 ◽  
pp. 107152
Author(s):  
Kai Zhang ◽  
Ming-Jia Li ◽  
Hua Liu ◽  
Jian-Guo Xiong ◽  
Ya-Ling He
Keyword(s):  
Rapid Method ◽  
Heat Exchangers ◽  
Flow Maldistribution

Experimental and Theoretical Analysis of Transient Response of Plate Heat Exchangers in Presence of Nonuniform Flow Distribution

2008 ◽  
Vol 130 (5) ◽  
Author(s):  
N. Srihari ◽  
Sarit K. Das
Keyword(s):  
Steady State ◽  
Heat Exchangers ◽  
Sudden Change ◽  
Temperature Response ◽  
Flow Distribution ◽  
Transient Temperature ◽  
Nonuniform Flow ◽  
Flow Rates ◽  
Plate Heat ◽  
Flow Maldistribution

Transient analysis helps us to predict the behavior of heat exchangers subjected to various operational disturbances due to sudden change in temperature or flow rates of the working fluids. The present experimental analysis deals with the effect of flow distribution on the transient temperature response for U-type and Z-type plate heat exchangers. The experiments have been carried out with uniform and nonuniform flow distributions for various flow rates. The temperature responses are analyzed for various transient characteristics, such as initial delay and time constant. It is also possible to observe the steady state characteristics after the responses reach asymptotic values. The experimental observations indicate that the Z-type flow configuration is more strongly affected by flow maldistribution compared to the U-type in both transient and steady state regimes. The comparison of the experimental results with numerical solution indicates that it is necessary to treat the flow maldistribution separately from axial thermal dispersion during modeling of plate heat exchanger dynamics.

Flow maldistribution in heat exchangers

1999 ◽  
Vol 19 (8) ◽  
pp. 847-863 ◽  
Author(s):  
S. Lalot ◽  
P. Florent ◽  
S.K. Lang ◽  
A.E. Bergles
Keyword(s):  
Heat Exchangers ◽  
Flow Maldistribution

scholarly journals Numerical Study of Flow Maldistribution in Multi-Plate Heat Exchangers Based on Robust 2D Model

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3121 ◽  
Author(s):  
Arkadiusz Brenk ◽  
Pawel Pluszka ◽  
Ziemowit Malecha
Keyword(s):  
Heat Exchangers ◽  
Numerical Study ◽  
High Heat ◽  
Pressure Balance ◽  
Plate Heat ◽  
Pressure Losses ◽  
Heat Transfer Efficiency ◽  
High Heat Transfer ◽  
Wide Range ◽  
Flow Maldistribution

Plate heat exchangers (PHE) are characterized by high heat transfer efficiency and compactness. An exploitation problem of the PHE is related to flow maldistribution, which can make part of the PHE idle, resulting in overheating and damage. Making geometrical modifications to the PHE can help reduce flow maldistribution. Modifications should be kept to a minimum, so as not to complicate the production process. There is a large number of possible geometrical modifications, which simply considers additional obstacles or stream dividers. To test all of them would be impractical and would also take a prohibitively long amount of time to obtain experimental measurements. A typical PHE is characterized by a complex system of channels. Making numerical calculations of its 3D model can be prohibitively time and resource-consuming. The present work introduces a physically consistent methodology of the transformation of a real 3D geometry to its 2D representation. Its main novelty is to assure the same pressure drop balance remains between the 3D and 2D geometries. This is achieved by a preservation of the same cumulative pressure losses in both geometries. The proposed innovative approach levels the pressure balance difference by adding properly designed local geometrical modifications. The developed methodology allowed a wide range of parameter space and various geometrical modifications to be investigated, and revealed geometrical optimizations leading to the improved performance of the PHE. To minimize the influence of other factors, an incompressible and single-phase flow was studied.

Flow Maldistribution Effects on the Temperature Uniformity in Double-Layered Microchannel Heat Sinks

2019 ◽  
Author(s):  
Carlo Nonino ◽  
Stefano Savino
Keyword(s):  
Thermal Resistance ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Total Mass ◽  
Cross Flow ◽  
Heat Sinks ◽  
Temperature Uniformity ◽  
Inlet Velocity ◽  
Microchannel Heat Sinks ◽  
Flow Maldistribution

Abstract A numerical investigation is carried out on the effects of flow maldistribution on the temperature uniformity and overall thermal resistance in double-layered microchannel heat sinks. Different flow maldistribution models accounting for the effects of some typical header designs are considered together with different combinations of the average inlet velocity in the two layers of microchannels for a given total mass flow rate. The numerical simulations are carried out using an in-house FEM procedure previously developed by the authors for the analysis of cross-flow microchannel heat exchangers.

Numerical simulation of flow distribution in the header of plate-fin heat exchanger

2020 ◽  
Vol 34 (14n16) ◽  
pp. 2040111
Author(s):  
Shu-Ling Tian ◽  
Ying-Ying Shen ◽  
Yao Li ◽  
Hai-Bo Wang ◽  
Sheryar Muhammad ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Optimization Design ◽  
High Efficiency ◽  
Flow Distribution ◽  
Optimal Number ◽  
Compact Structure ◽  
Flow Maldistribution

Plate-fin heat exchangers are widely used in industry at present due to their compact structure and high efficiency. However, there is a problem of flow maldistribution, resulting in poor performance of heat exchangers. The influence of the header configuration on fluid flow distribution is studied by using CFD software FLUENT. The numerical results show that the fluid flow inside the header is seriously uneven. The reliability of the numerical simulation is validated against the published results. They are found to be basically consistent within considerable error. The optimal number of the punch baffle is investigated. Various header configuration with different opening ratios have been studied under the same boundary conditions. The gross flow maldistribution parameter (S) is used to evaluate flow nonuniformity, and the flow maldistribution parameters of different schemes under different Reynolds numbers are listed and compared. The optimal header with minimum flow maldistribution parameter is obtained through the performance analysis of headers. It is found that the flow maldistribution of the improved header is significantly smaller compared with the conventional header. Hence, the efficiency of the heat exchanger is effectively enhanced. The conclusion provides a reference for the optimization design of plate-fin heat exchanger.

scholarly journals Analysis Exploring the Uniformity of Flow Distribution in Multi-Channels for the Application of Printed Circuit Heat Exchangers

Symmetry ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 314 ◽  
Author(s):  
Hanbing Ke ◽  
Yuansheng Lin ◽  
Zhiwu Ke ◽  
Qi Xiao ◽  
Zhiguo Wei ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Heat Exchangers ◽  
Electronic Device ◽  
Numerical Models ◽  
Sudden Change ◽  
Flow Distribution ◽  
Outer Radius ◽  
Air Separation ◽  
Printed Circuit ◽  
Flow Maldistribution

The maldistribution of fluid flow through multi-channels is a critical issue encountered in many areas, such as multi-channel heat exchangers, electronic device cooling, refrigeration and cryogenic devices, air separation and the petrochemical industry. In this paper, the uniformity of flow distribution in a printed circuit heat exchanger (PCHE) is investigated. The flow distribution and resistance characteristics of a PCHE plate are studied with numerical models under different flow distribution cases. The results show that the sudden change in the angle of the fluid at the inlet of the channel can be greatly reduced by using a spreader plate with an equal inner and outer radius. The flow separation of the fluid at the inlet of the channel can also be weakened and the imbalance of flow distribution in the channel can be reduced. Therefore, the flow uniformity can be improved and the pressure loss between the inlet and outlet of PCHEs can be reduced. The flow maldistribution in each PCHE channel can be reduced to ± 0.2%, and the average flow maldistribution in all PCHE channels can be reduced to less than 5% when the number of manifolds reaches nine. The numerical simulation of fluid flow distribution can provide guidance for the subsequent research and the design and development of multi-channel heat exchangers. In summary, the symmetry of the fluid flow in multi-channels for PCHE was analyzed in this work. This work presents the frequently encountered problem of maldistribution of fluid flow in engineering, and the performance promotion leads to symmetrical aspects in both the structure and the physical process.

Effect of Flow Maldistribution and Viscosity Variations on Transient Response of Plate Heat Exchangers: A Comparison With Uniform Flow and Constant Viscosity Model

Volume 1 ◽  
2004 ◽  
Author(s):  
H. Shokouhmand ◽  
N. Khareghani
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Transient Response ◽  
Heat Exchangers ◽  
Uniform Flow ◽  
Viscosity Model ◽  
Step Response ◽  
Plate Heat ◽  
Constant Viscosity ◽  
Flow Maldistribution

In this paper, transient response of plate heat exchangers under flow maldistribution and viscosity variations is discussed. This transient response is compared with the response achieved from uniform flow and constant viscosity through the exchanger. Flow maldistribution (unequal flow in channels) is calculated for U and Z types of plate heat exchangers. This flow maldistribution along with viscosity variations, during the growth of the temperature profile in each channel, affect the convective heat transfer coefficient in the transient period of heat transfer, and make it to be different from that of the other channels. These conditions make the transient response of a plate heat exchanger to have some deviations from the uniform flow and constant viscosity model response, which is discussed in this paper. The governing equations of heat transfer are solved using finite difference methods. Frequency response as well as step response of the heat exchanger is implemented as a time dependent initial conditions.

Experimental Investigation on Port-to-Channel Flow Maldistribution in Plate Heat Exchangers

2007 ◽  
Vol 28 (5) ◽  
pp. 435-443 ◽  
Author(s):  
Fantu A. Tereda ◽  
N. Srihari ◽  
Bengt Sunden ◽  
Sarit K. Das
Keyword(s):  
Experimental Investigation ◽  
Channel Flow ◽  
Heat Exchangers ◽  
Plate Heat ◽  
Flow Maldistribution

Steam Condensation in Parallel Channels of Plate Heat Exchangers

2010 ◽  
Author(s):  
Prabhakara Rao Bobbili ◽  
Bengt Sunden
Keyword(s):  
Heat Exchanger ◽  
Heat Exchangers ◽  
Flow Distribution ◽  
Small Degree ◽  
Flow Conditions ◽  
Steam Condensation ◽  
Cooling Fluid ◽  
Plate Heat ◽  
Parallel Channels ◽  
Flow Maldistribution

An experimental investigation has been carried out to find the nature of temperature profiles of the process and cooling fluids during steam condensation across the port to channel in plate heat exchangers (PHEs). In the present study, low corrugation angle (30°) plates have been used for different plate package of PHEs with 41 and 81 plates. The process steam entered at 1 bar with a small degree of superheat. Water has been used as the cold fluid. A traverse temperature probe is inserted into both inlet and outlet ports of the plate heat exchanger. The temperature of the process steam and cooling fluid have been measured and recorded at the location of first, middle and last channels for different inlet and exit flow conditions for each plate package of the heat exchanger. Also, the overall pressure drop has been measured at different conditions at the outlet of the process steam, i.e., full and partial condensation. The traverse temperature measurements have indicated that there is a considerable variation in temperature along inlets and outlets of process steam and cooling fluid, due to flow maldistribution. The experimental data has been analyzed to show how the flow distribution on the cooling side affects the condensation of steam in plate heat exchangers. The present results will help to study further the nature of steam condensation in parallel channels of heat exchangers.

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