scholarly journals Improvement of Flow Distribution by New Inlet Header Configuration with Splitter Plates for Plate-Fin Heat Exchanger

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1323 ◽  
Author(s):  
Xiang Peng ◽  
Denghong Li ◽  
Jiquan Li ◽  
Shaofei Jiang ◽  
Qilong Gao
Keyword(s):  
Heat Exchanger ◽  
Pressure Drop ◽  
Fluid Dynamic ◽  
Structural Parameters ◽  
Flow Distribution ◽  
Two Stage ◽  
Optimum Configuration ◽  
Splitter Plates ◽  
Inclined Angle ◽  
Flow Maldistribution

The pressure drop increases along with the decrease in the flow maldistribution in the two-stage distributing inlet headers of a plate-fin heat exchanger. To solve this issue, we proposed a new inlet header configuration with splitter plates to decrease the flow maldistribution and pressure drop simultaneously. We used computational fluid dynamic technology to analyze the flow properties in the inlet header configuration and calculated the flow maldistribution degree of the outlet channels and the pressure drop in the inlet header. We performed a sensitivity analysis between the structural parameters, the flow maldistribution degree, and the pressure drop. We determined the optimum values of the structural parameters (the construction of transition duct, the number of splitter plates, the inclined angle of outermost plates, the height of splitter plates, the height of inlet header, etc.), and acquired the optimum configuration of the improved inlet header. Compared with the traditional inlet header, the flow maldistribution degree and pressure drop decreased by 91.5% and 40.9%, respectively, using the proposed improved inlet header with splitter plates, which performed better than the conventional two-stage distribution inlet header.

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.

Numerical Simulation Applied to Study the Effects of Fractal Tree-Liked Network Channel Designs on PEMFC Performance

2012 ◽  
Vol 488-489 ◽  
pp. 1219-1223 ◽  
Author(s):  
Shan Jen Cheng ◽  
Jr Ming Miao ◽  
Chang Hsien Tai
Keyword(s):  
Fuel Cell ◽  
Pressure Drop ◽  
Flow Field ◽  
Fluid Dynamic ◽  
Flow Distribution ◽  
Flow Channel ◽  
Proton Exchange ◽  
Channel Network ◽  
Computational Fluid Dynamic Analysis ◽  
Network Channel

The effect of pressure drop and the flow-field of inhomogeneous transport of reactions gas are two important issues for bipolar flow channel design in proton exchange membrane fuel cell (PEMFC). A novel design through the imitation of biological development of the topology distribution of fractal tree-liked network channel is the main topic of this research. The effects of different Reynolds numbers and stoichiometric mass flow rate of reaction gas on the flow field distribution of tree-like channels were investigated by three-dimensional computational fluid dynamic analysis. According to numerical simulations, the fractal tree-liked network channel would have an excellent performance on the uniformity of multi-branching flow distribution and lower pressure drop along channels. The new type of fractal tree-liked bionic flow channel network design will be applied to assist in the experimental reference for improving the performance of fuel cell stack system in PEMFC for future.

A Numerical Study of Flow and Temperature Maldistribution in a Parallel Microchannel System for Heat Removal in Microelectronic Devices

2012 ◽  
Author(s):  
Manoj Siva ◽  
Arvind Pattamatta ◽  
Sarit Kumar Das
Keyword(s):  
Heat Exchanger ◽  
Cross Section ◽  
Design Theory ◽  
Cooling System ◽  
Search Algorithm ◽  
Numerical Study ◽  
Heat Removal ◽  
Flow Distribution ◽  
Microchannel Cooling ◽  
Flow Maldistribution

A common assumption in basic heat exchanger design theory is that fluid is distributed uniformly at the inlet of the exchanger on each fluid side and throughout the core. However in reality, uniform flow distribution is never achieved in a heat exchanger and is referred to as flow maldistribution. Flow maldistribution is generally well understood for the macrochannel system. But it is still unclear whether the assumptions underlying the flow distribution in conventional macrochannel heat exchangers hold good for microchannel system. In this regard, extensive numerical simulations are carried out in a ‘U’ type parallel micro-channel system in order to study flow and heat transfer maldistribution and validated with in-house experimental data. A detailed parametric analysis is carried out to characterize flow maldistribution in a microchannel system and to study the effect of geometrical factors such as number of channels, n, Area of cross section of the channel Ac, manifold cross section area Ap, and flow parameter such as Reynolds number, Re, on the pressure and temperature distribution. In order to minimize the variation in pressure and to reduce temperature hot spots in the microchannel, a Response surface based surrogate approximation (RSA) and a gradient based search algorithm are used to arrive at the best configuration of microchannel cooling system. A three level factorial design involving three parameters namely Ac/Ap, Re, n are considered. The results from the optimization indicate that the case of n = 5, Ac/Ap = 0.12, and Re = 100 is the best possible configuration to alleviate flow maldistribution and hotspot formation in microchannel cooling system.

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.

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.

A Numerical Study of Flow and Temperature Maldistribution in a Parallel Microchannel System for Heat Removal in Microelectronic Devices

2013 ◽  
Vol 5 (4) ◽  
Author(s):  
V. Manoj Siva ◽  
Arvind Pattamatta ◽  
Sarit Kumar Das
Keyword(s):  
Heat Exchanger ◽  
Cross Section ◽  
Design Theory ◽  
Cooling System ◽  
Search Algorithm ◽  
Numerical Study ◽  
Heat Removal ◽  
Flow Distribution ◽  
Microchannel Cooling ◽  
Flow Maldistribution

A common assumption in basic heat exchanger design theory is that fluid is distributed uniformly at the inlet of the exchanger on each fluid side and throughout the core. However, in reality, uniform flow distribution is never achieved in a heat exchanger and is referred to as flow maldistribution. Flow maldistribution is generally well understood for the macrochannel system. But it is still unclear whether the assumptions underlying the flow distribution in conventional macrochannel heat exchangers hold good for microchannel system. In this regard, extensive numerical simulations are carried out in a “U” type parallel microchannel system in order to study flow and heat transfer maldistribution and validated with in-house experimental data. A detailed parametric analysis is carried out to characterize flow maldistribution in a microchannel system and to study the effect of geometrical factors such as number of channels, n, Area of cross section of the channel Ac, manifold cross section area Ap, and flow parameter such as Reynolds number, Re, on the pressure and temperature distribution. In order to minimize the variation in pressure and to reduce temperature hot spots in the microchannel, a response surface based surrogate approximation and a gradient based search algorithm are used to arrive at the best configuration of microchannel cooling system. A three level factorial design involving three parameters namely Ac/Ap, Re, n are considered. The results from the optimization indicate that the case of n = 7, Ac/Ap = 0.69, and Re = 100 is the best possible configuration to alleviate flow maldistribution and hotspot formation in microchannel cooling system.

Flow Maldistribution in a Simplified Plate Heat Exchanger Model - A Numerical Study

2011 ◽  
Vol 110-116 ◽  
pp. 2529-2536 ◽  
Author(s):  
Nityanand Pawar ◽  
R.S. Maurya
Keyword(s):  
Heat Exchanger ◽  
Uniform Distribution ◽  
Numerical Study ◽  
Flow Distribution ◽  
Plate Heat Exchanger ◽  
Design Parameters ◽  
Process Equipment ◽  
Numerical Work ◽  
Plate Heat ◽  
Flow Maldistribution

The performance of a plate heat exchanger (PHE) is severely influenced by non-uniform distribution of flow among its channels. Not only the PHEs, but many other process equipment needs uniform flow distribution for their optimum performance. Flow maldistribution (non-uniform distribution) is a common design problem which always puzzles process equipment designers. Being important design parameters, it has been investigated by several researchers and case based solution has been proposed and documented. Present numerical work is intended to target this aspect of the problem of PHEs but starts with a general investigation with simple multichannel geometry. The numerical setup consists of two headers having multiple channels for U-and Z-turn flow configuration under multichannel geometry and a simplified PHE for plate heat exchanger simulation. The problem has been investigated from hydrodynamic and thermodynamic view point. For hydrodynamic study, flow has been varied for Reynolds number 120 to 17600. It has been found that channel flow goes on reducing along downstream side. In thermal study the effect of wall temperature on air flow mal distribution has been investigated. Numerical results have been validated with the experimental results. Investigation reveals new features of flow mal-distribution which is helpful in better understanding of associated mal-distribution physics.

scholarly journals On the Use of Dual Cell Density Monoliths

Catalysts ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1075
Author(s):  
Ivan Cornejo ◽  
Gonzalo Garreton ◽  
Robert E. Hayes
Keyword(s):  
Pressure Drop ◽  
Cell Density ◽  
Conversion Efficiency ◽  
Flow Distribution ◽  
Apparent Permeability ◽  
Diffusion Limitations ◽  
Relevant Evidence ◽  
Automotive Catalytic Converters ◽  
Flow Maldistribution ◽  
The Impact

Monolith-type substrates are extensively used in automotive catalytic converters and have gained popularity in several other industrial processes. Despite their advantages over traditional unstructured catalysts, such as large surface area and low pressure drop, novel monolith configurations have not been investigated in depth. In this paper, we use a detailed computational model at the reactor scale, which considers entrance length, turbulence dissipation and internal diffusion limitations, to investigate the impact of using a dual cell substrate on conversion efficiency, pressure drop, and flow distribution. The substrate is divided into two concentric regions, one at its core and one at its periphery, and a different cell density is given to each part. According to the results, a difference of 40% in apparent permeability is sufficient to lead to a large flow maldistribution, which impacts conversion efficiency and pressure drop. The two mentioned variables show a positive or negative correlation depending on what part of the substrate—core or ring—has the highest permeability. This and other results contribute relevant evidence for further monolith optimization.

CFD Optimization of Gas-Side Flow Channel Configuration Inside a High Temperature Bayonet Tube Heat Exchanger With Inner and Outer Fins

2011 ◽  
Author(s):  
T. Ma ◽  
Y. P. Ji ◽  
M. Zeng ◽  
Q. W. Wang
Keyword(s):  
Reynolds Number ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Flow Distribution ◽  
Flow Channel ◽  
Original Design ◽  
Tube Heat Exchanger ◽  
Channel Configuration ◽  
Model C ◽  
Side Flow

In this paper, the gas-side fluid flow distribution inside a bayonet tube heat exchanger with inner and outer fins is numerically studied. The heat exchanger is designed based on the traditional bayonet tube heat exchanger, where compact continuous plain fins and wave-like fins are mounted on the outside and inside surfaces of outer tubes, respectively, to enhance the heat transfer performance. However, gross flow maldistribution and large vortices are observed in the gas-side flow channel of baseline design. In order to improve the flow uniformity, three modified designs are proposed. Three vertical plates and two inclined plates are mounted on the inlet manifold for Model B. For the Model C, another six bending plates are mounted on the middle manifolds and three pairs of them are connected together. The Model D has a similar structure as Model C except for the two additional baffles. The results indicate that the flow distributions of Model C and D are much more uniform under different inlet Reynolds number, especially in the high inlet Reynolds number. Although the flow distribution of Model D is the best, its pressure drop is 2.6 times higher than that of Model C. Therefore, the design of Model C is the most optimized structure. Compared with the original design, the nonuniformity of Model C can be reduced by 42% while the pressure drop is almost the same under the baseline condition.

CFD Simulation on Flow Distribution in Plate-Fin Heat Exchangers

2013 ◽  
Vol 655-657 ◽  
pp. 445-448
Author(s):  
Zhe Zhang ◽  
Jin Jin Tian ◽  
Yong Gang Guo
Keyword(s):  
Fluid Flow ◽  
Heat Exchanger ◽  
Cfd Simulation ◽  
Perforated Plate ◽  
Flow Distribution ◽  
Numerical Results ◽  
Flow Maldistribution ◽  
The Mathematical Model ◽  
First Time ◽  
Flow Nonuniformity

The influences of the conventional header configuration used in industry at present on the fluid flow distribution in plate-fin heat exchanger were numerically investigated. The numerical results showed that the fluid flow maldistribution is very serious in the heat exchanger. The header configuration with perforated plate was brought forward for the first time. The computational results indicated that the improved header configuration can effectively improve the performance of fluid flow distribution in the heat exchanger. The fluid flow distribution for the header configuration with curving perforated plate is more uniform than for the header configuration with plane perforated plate. The absolute degree of fluid flow nonuniformity in plate-fin heat exchanger has reduced from 3.47 to 0.32 by changing the header configuration. The numerical results are compared with the experimental results. They are basically consistent which indicates that the mathematical model and the calculating method are reliable.

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