Heat capacity ratio and the best type of heat exchanger for geothermal water providing maximum heat transfer

Energy ◽  
2015 ◽  
Vol 90 ◽  
pp. 1563-1568 ◽  
Author(s):  
Özden Ağra ◽  
Hasan Hüseyin Erdem ◽  
Hakan Demir ◽  
Ş. Özgür Atayılmaz ◽  
İsmail Teke
Keyword(s):  
Heat Transfer ◽  
Heat Capacity ◽  
Heat Exchanger ◽  
Geothermal Water ◽  
Maximum Heat ◽  
Capacity Ratio ◽  
Maximum Heat Transfer

scholarly journals Numerical Study on Flow and Heat Transfer Mechanisms in the Heat Exchanger Channel with V-Orifice at Various Blockage Ratios, Gap Spacing Ratios, and Flow Directions

2019 ◽  
Vol 2019 ◽  
pp. 1-21 ◽  
Author(s):  
Amnart Boonloi ◽  
Withada Jedsadaratanachai
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Numerical Study ◽  
Numerical Results ◽  
Blockage Ratio ◽  
Maximum Heat ◽  
Flow And Heat Transfer ◽  
Maximum Heat Transfer ◽  
Smooth Channel ◽  
Gap Spacing

Numerical assessments in the square channel heat exchanger installed with various parameters of V-orifices are presented. The V-orifice is installed in the heat exchanger channel with gap spacing between the upper-lower edges of the orifice and the channel wall. The purposes of the design are to reduce the pressure loss, increase the vortex strength, and increase the turbulent mixing of the flow. The influence of the blockage ratio and V-orifice arrangement is investigated. The blockage ratio, b/H, of the V-orifice is varied in the range 0.05–0.30. The V-tip of the V-orifice pointing downstream (V-downstream) is compared with the V-tip pointing upstream (V-upstream) by both flow and heat transfer. The numerical results are reported in terms of flow visualization and heat transfer pattern in the test section. The thermal performance assessments in terms of Nusselt number, friction factor, and thermal enhancement factor are also concluded. The numerical results reveal that the maximum heat transfer enhancement is found to be around 26.13 times higher than the smooth channel, while the optimum TEF is around 3.2. The suggested gap spacing for the present configuration of the V-orifice channel is around 5–10%.

Heat Transfer Study of Staggered Thin Rectangular Blocks in a Channel Flow

1991 ◽  
Vol 113 (3) ◽  
pp. 294-300 ◽  
Author(s):  
Ching Jen Chen ◽  
Ramiro H. Bravo
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Channel Flow ◽  
Vector Fields ◽  
Block Size ◽  
Navier Stokes ◽  
Maximum Heat ◽  
Flow And Heat Transfer ◽  
Maximum Heat Transfer ◽  
Energy Equations

In this study, fluid flow and heat transfer in two-dimensional staggered thin rectangular blocks in a channel flow heat exchanger is analyzed by the Finite Analytic Numerical Method. The heat exchanger consists of four staggered thin rectangular blocks at temperature T1 placed inside a channel which is formed by two plates maintained at constant temperature T0. The fluid is considered to be incompressible and the flow laminar. Flow and heat transfer from the inlet of the heat exchanger to the outlet are simulated by solving Navier-Stokes and energy equations. Results were obtained for different block spacing and different size of the blocks. Computations were made for Reynolds numbers 100, 500, and 1,000, and Prandtl numbers 0.7 and 4.0. The results are presented in the form of velocity vector fields, isotherms, and local and global Nusselt numbers. The characteristics of the heat transfer and pressure drop in different block size and block separation are analyzed. The optimal length of separation between thin blocks and the optimal block length for maximum heat transfer are determined.

scholarly journals Enhancing Heat Transfer in Tube Heat Exchanger by Inserting Discrete Twisting Tapes with Different Positions

2019 ◽  
Vol 25 (8) ◽  
pp. 39-51
Author(s):  
Nassr Fadhil Hussein ◽  
Abdulrahman Shakir Mahmood
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Constant Heat Flux ◽  
Vertical Position ◽  
Maximum Heat ◽  
Tube Heat Exchanger ◽  
Twisted Tapes ◽  
Maximum Heat Transfer

Enhancement of heat transfer in the tube heat exchanger is studied experimentally by using discrete twisted tapes. Three different positions were selected for inserting turbulators along tube section (horizontal position by α= 00, inclined position by α= 45 0 and vertical position by α= 900). The space between turbulators was fixed by distributing 5 pieces of these turbulators with pitch ratio    PR = (0.44). Also, the factor of constant heat flux was applied as a boundary condition around the tube test section for all experiments of this investigation, while the flow rates were selected as a variable factor (Reynolds number values vary from 5000 to 15000). The results show that using discrete twisted tapes enhances the heat transfer rate by about 60.7-103.7 % compared with plane tube case. Also, inserting turbulators with inclined position offers maximum heat transfer rate by 103.7%.  

Simulation and Analysis of Air Performance of Multi-Row Finned-Tube Heat Exchanger

2011 ◽  
Vol 347-353 ◽  
pp. 2519-2523
Author(s):  
Wen Wen Wang ◽  
Rui Li
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Finned Tube ◽  
Mathematics Model ◽  
Maximum Heat ◽  
Tube Heat Exchanger ◽  
Heat Transfer Efficiency ◽  
Maximum Heat Transfer ◽  
Finned Tube Heat Exchanger ◽  
Pressure Changes

In this paper, simulates the air performance of multi-row finned-tube heat exchanger by Fluent. The mathematics model is established, using standard k-ε turbulence model. The temperature, velocity and pressure changes of air are analyzed. By research the multi-row finned-tube heat exchanger, analyzed the different structures have different effects on the efficiency of heat transfer, obtained the most appropriate number of tube rows, making the heat exchanger for maximum heat transfer efficiency.

Heat Transfer to Water-Oxygen Mixtures at High Pressure

2002 ◽  
Author(s):  
S. N. Rogak ◽  
S. Boskovic ◽  
D. Faraji
Keyword(s):  
Heat Transfer ◽  
Heat Capacity ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Water Oxidation ◽  
Pure Water ◽  
Heat Fluxes ◽  
Maximum Heat ◽  
Water Oxygen ◽  
Maximum Heat Transfer

The constant pressure heat capacity and forced convection heat transfer coefficient was measured in a horizontal, smooth, electrically-heated tube. For the supercritical pressures considered, flow rates and temperatures (330–430 °C), the flow in the 6.2 mm ID tube was fully turbulent. The fluid was distilled water and up to 9 wt% oxygen. This mixture and the experimental conditions are found in supercritical water oxidation systems. At subcritical temperatures, the oxygen and water are almost immiscible, but just below the critical temperature, the fluid becomes single-phase. By measuring bulk and surface temperatures, knowing the mass and heat flux, both the heat capacity and heat transfer coefficient could be measured. The water-oxygen system is a highly non-ideal mixture, and small amounts of oxygen significantly reduce the temperature at which maximum heat transfer occurs. The changes in heat capacity appear to dominate the effect of oxygen on heat transfer, however, the mixtures do exhibit heat transfer deterioration at slightly subcritical temperatures, at flows and heat fluxes for which pure water shows nothing similar.

THE ANALYSIS OF EXERGY EFFICIENCY IN THE LOW TEMPERATURE HEAT EXCHANGER

2007 ◽  
Vol 21 (18n19) ◽  
pp. 3497-3499 ◽  
Author(s):  
LAN PENG ◽  
YOU-RONG LI ◽  
SHUANG-YING WU ◽  
BO LAN
Keyword(s):  
Heat Transfer ◽  
Heat Capacity ◽  
Heat Exchanger ◽  
Low Temperature ◽  
Transfer Process ◽  
Heat Exchangers ◽  
Heat Transfer Process ◽  
Exergy Efficiency ◽  
Capacity Ratio ◽  
Temperature Heat

Based on the analyzing of the thermodynamic performance of the heat transfer process in the low temperature heat exchangers, the exergy efficiency of the heat transfer process is defined and a general expression for the exergy efficiency is derived, which can be used to discuss the effect of heat transfer units number and heat capacity ratio of fluids on the exergy efficiency of the low temperature heat exchanger. The variation of the exergy efficiency for several kinds of flow patterns in the low heat exchangers is compared and the calculating method of the optimal values of heat capacity ratio for the maximum exergy efficiency is given.

scholarly journals Optimization Performance on Plate Fin Tube Heat Exchanger

2019 ◽  
Vol 5 (3) ◽  
pp. 10
Author(s):  
Mahtab Alam ◽  
Dr. Dharmendra Singh Rajput
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Circular Tube ◽  
Fluid Dynamic ◽  
Cfd Analysis ◽  
Maximum Heat ◽  
Tube Heat Exchanger ◽  
Tube Arrangement ◽  
Maximum Heat Transfer ◽  
Fin Tube

The main objective of the present work is to investigation of optimum design of plate fin tube heat exchanger using Computational fluid dynamic approach and maximizing thermal performance. There are total five designs of plate fin and tube heat exchanger are used in present work and CFD analysis have been performed in it to get maximum heat transfer. It has been observed from CFD analysis that the maximum heat transfer can be achieved from plate fin and tube heat exchanger with elliptical tube arrangement inclined at 30o with 23.22% more heat transfer capacity as compared to circular tube plate pin heat exchanger. So that it is recommended that if the plate fins and tube heat exchanger with inclined elliptical tube used in place of circular tube arrangement, batter heat transfer can be achieved.

scholarly journals A heat pipe heat recovery heat exchanger for a mini-drier

2006 ◽  
Vol 17 (1) ◽  
pp. 50-57 ◽  
Author(s):  
A Meyer ◽  
R T R T Dobson
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Theoretical Model ◽  
Heat Pipe ◽  
Experimental Testing ◽  
Thermal Design ◽  
Working Fluid ◽  
Transfer Coefficients ◽  
Maximum Heat ◽  
Maximum Heat Transfer

This paper considers the thermal design and the experimental testing of a heat pipe (thermosyphon) heat exchanger for a relatively small commercially available mini-drier. The purpose of the heat exchanger is to recover heat from the moist waste air stream to preheat the fresh incoming air. The working fluid used was R134a and the correlations are given for the evaporator and condenser inside heat transfer coefficients as well as for the maximum heat transfer rate. The theoretical model and computer simulation program used for the thermal design calculations are described. The validity of the as-designed and manufactured heat exchanger coupled to the drier is experimentally verified. The theoretical model accurately predicted the thermal performance and a significant energy savings and a reasonable payback period was achieved.

Optimization of Finned Ducts in Laminar Flow

1984 ◽  
Vol 106 (3) ◽  
pp. 586-590 ◽  
Author(s):  
M. Kovarik
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Natural Convection ◽  
Heat Exchanger ◽  
Laminar Flow ◽  
Unit Cost ◽  
Necessary Condition ◽  
Maximum Heat ◽  
Maximum Heat Transfer ◽  
Necessary Condition Of Optimality

A simple necessary condition of optimality for a finned heat exchanger duct in laminar flow is derived. The criterion of optimality is maximum heat transfer from the fin per unit cost of the finned duct. The heat transfer is determined by the conjugate convection-conduction process rather than by the assumption of a given heat transfer coefficient on the fin surface. Both forced and natural convection are considered. Expressions comparing the performance of optimal assemblies of different materials are given. Approximate dimensions of optimal fins are derived. The relations between the present and earlier results are discussed.

scholarly journals Optimizing Thermal Behavior of Flat Plate Heat Exchanger Tube by Varying Geometrical Configuration

2020 ◽  
pp. 13-25
Author(s):  
Nitesh Kumar Singh
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Circular Tube ◽  
Fluid Dynamic ◽  
High Ratio ◽  
Cfd Analysis ◽  
Maximum Heat ◽  
Tube Heat Exchanger ◽  
Tube Arrangement ◽  
Maximum Heat Transfer

A plate fin heat exchanger is a type of heat exchanger design that uses plates and finned chambers to transfer heat between liquids. It is often classified as a compact heat exchanger to emphasize the relatively high ratio between the heat transfer surface and the volume. The main objective of the present work is to investigation of optimum design of plate fin tube heat exchanger using Computational fluid dynamic approach and maximizing thermal performance. There are total five designs of plate fin and tube heat exchanger are used in present work and CFD analysis have been performed in it to get maximum heat transfer. It has been observed from CFD analysis that the maximum heat transfer can be achieved from plate fin and tube heat exchanger with elliptical tube arrangement inclined at 30o with 23.22% more heat transfer capacity as compared to circular tube plate pin heat exchanger. So that it is recommended that if the plate fins and tube heat exchanger with inclined elliptical tube used in place of circular tube arrangement, batter heat transfer can be achieved.

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