A Correlation for the Heat Conduction Effects in Counterflow Rotary Regenerative Heat Exchangers

1993 ◽  
Vol 115 (4) ◽  
pp. 287-290 ◽  
Author(s):  
C. M. Shen ◽  
W. M. Worek
Keyword(s):  
Heat Capacity ◽  
Fluid Flow ◽  
Heat Conduction ◽  
Heat Exchangers ◽  
Flow Direction ◽  
Performance Comparison ◽  
Regenerative Heat ◽  
Numerical Predictions ◽  
The Matrix ◽  
Biot Numbers

Equations that predict the dependence of regenerator effectiveness on heat conduction in the matrix both parallel to and perpendicular to the fluid flow are derived from numerical simulations. The equations developed use Biot numbers parallel to the direction of fluid flow (Bix) and perpendicular to the fluid flow direction (Biy), the ratio of heat capacity rates (C*), the heat capacity rate ratio (C*Γ), and the overall number of transfer units (NTUo) to characterize the regenerator performance. Comparison of numerical predictions with those obtained using the equations developed in this paper show excellent agreement. These equations enable designers to accurately account for two-dimensional conduction effects when regenerators are designed.

scholarly journals The influence of main parameters of regenerative heat exchanger on its energy efficiency

2020 ◽  
Vol 178 ◽  
pp. 01024
Author(s):  
Nikolay Monarkin ◽  
Anton Sinitsyn ◽  
Mikhail Pavlov ◽  
Timur Akhmetov
Keyword(s):  
Energy Efficiency ◽  
Heat Capacity ◽  
Heat Exchanger ◽  
Wall Thickness ◽  
Thermal Energy ◽  
Thermal Efficiency ◽  
Heat Exchangers ◽  
Regenerative Heat ◽  
Flow Through ◽  
Geometric Length

The influence of various parameters of stationary switching regenerative heat exchangers used for ventilation on its thermal efficiency was studied. Considered are the geometric (length, diameter and wall thickness of a single equivalent nozzle channel), thermophysical (density and heat capacity of the nozzle material) and operation (air flow through the regenerator and the time of one stage of accumulation/regeneration of thermal energy) parameters.

scholarly journals Method for designing energy-efficient ventilation systems based on regenerative heat exchangers

2020 ◽  
Vol 178 ◽  
pp. 01037
Author(s):  
Nikolay Monarkin ◽  
Anton Sinitsyn ◽  
Denis Karpov ◽  
Timur Akhmetov
Keyword(s):  
Heat Capacity ◽  
Heat Exchangers ◽  
Energy Efficient ◽  
Channel Wall ◽  
Single Channel ◽  
Air Flow Rate ◽  
Heat Accumulation ◽  
Regenerative Heat ◽  
Selection Of ◽  
Ventilation Systems

The method of designing ventilation systems based on stationary switching regenerative heat exchangers is presented. Recommendations for selection of rational device parameters are given and substantiated. The diameter and thickness of a single channel wall of regenerative nozzle; the total diameter and length of nozzle; the time of heat accumulation or regeneration stages; the heat capacity and density of nozzle material; air flow rate are considered.

Performance Comparison of Rod-Baffle and Segment-Baffle Heat Exchangers Using Numerical Simulations

2014 ◽  
Vol 595 ◽  
pp. 128-133 ◽  
Author(s):  
Yuan Zhe Cao ◽  
Liu Juan Zhu ◽  
Yan Hua Shi
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Comparative Study ◽  
Numerical Simulations ◽  
Heat Exchangers ◽  
Performance Comparison ◽  
Shell Side ◽  
Design And Optimization ◽  
Shell And Tube ◽  
Insight Into

A comparative study on performances of rod-baffle (RB) and segment-baffle (SB) heat exchangers was carried out by numerical simulations under the same conditions. The results show that the overall heat transfer efficiencies are similar in these two types of heat exchangers with the same heat transfer areas. But RB heat exchangers show more uniform and smooth fluid flow, as well as much lower pressure in the shell side compared to SB counterparts. These detailed characteristics of heat transfer and fluid flow evidence better performances in RB heat exchangers and also provide a deeper insight into design and optimization of shell-and-tube heat exchangers.

Thermal Performance and Sizing of Moving Bed Heat Exchangers

2014 ◽  
Author(s):  
Pedro Isaza ◽  
W. David Warnica ◽  
Markus Bussmann
Keyword(s):  
Heat Capacity ◽  
Heat Conduction ◽  
Heat Exchanger ◽  
Thermal Performance ◽  
Biot Number ◽  
Heat Exchangers ◽  
Moving Bed ◽  
Thermal Transfer ◽  
Central Receiver ◽  
Condition C

A novel thermal performance relation is presented for a moving bed heat exchanger (MBHE) and its application is demonstrated via a sample rating calculation. Unlike conventional fluid-fluid heat exchangers, where effectiveness relations are a function of the heat capacity ratio, C, and the number of thermal transfer units, NTU, the MBHE expression also depends on the Biot number, Bi, due to heat conduction in the solids. The effectiveness curve for an MBHE operating under the special condition C = 0 is presented, along with its application to a proposed system for solar central receiver plants [1].

Numerical analysis of compact plate-fin heat exchangers for aerospace applications

2018 ◽  
Vol 28 (2) ◽  
pp. 395-412 ◽  
Author(s):  
Ranganayakulu Chennu
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Heat Conduction ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
Cross Flow ◽  
Design Data ◽  
Content Type ◽  
Compact Heat Exchangers ◽  
Performance Deterioration

Purpose The purpose of this study is to find the thermo-hydraulic performances of compact heat exchangers (CHE’s), which are strongly depending upon the prediction of performance of various types of heat transfer surfaces such as offset strip fins, wavy fins, rectangular fins, triangular fins, triangular and rectangular perforated fins in terms of Colburn “j” and Fanning friction “f” factors. Design/methodology/approach Numerical methods play a major role for analysis of compact plate-fin heat exchangers, which are cost-effective and fast. This paper presents the on-going research and work carried out earlier for single-phase steady-state heat transfer and pressure drop analysis on CHE passages and fins. An analysis of a cross-flow plate-fin compact heat exchanger, accounting for the individual effects of two-dimensional longitudinal heat conduction through the exchanger wall, inlet fluid flow maldistribution and inlet temperature non-uniformity are carried out using a Finite Element Method (FEM). Findings The performance deterioration of high-efficiency cross-flow plate-fin compact heat exchangers have been reviewed with the combined effects of wall longitudinal heat conduction and inlet fluid flow/temperature non-uniformity using a dedicated FEM analysis. It is found that the performance deterioration is quite significant in some typical applications due to the effects of wall longitudinal heat conduction and inlet fluid flow non-uniformity on cross-flow plate-fin heat exchangers. A Computational Fluid Dynamics (CFD) program FLUENT has been used to predict the design data in terms of “j” and “f” factors for plate-fin heat exchanger fins. The suitable design data are generated using CFD analysis covering the laminar, transition and turbulent flow regimes for various types of fins. Originality/value The correlations for the friction factor “f” and Colburn factor “j” have been found to be good. The correlations can be used by the heat exchanger designers and can reduce the number of tests and modification of the prototype to a minimum for similar applications and types of fins.

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