Second law thermodynamic analysis of imbalanced counter flow heat exchanger for energy conservation

2020 ◽  
pp. 250-262
Author(s):  
K. Manjunath
Keyword(s):  
Heat Exchanger ◽  
Energy Conservation ◽  
Entropy Generation ◽  
Diameter Ratio ◽  
Second Law ◽  
Exergetic Efficiency ◽  
Minimum Entropy ◽  
Counter Flow ◽  
Flow Heat ◽  
Length To Diameter Ratio

Entropy generation of imbalanced counter flow heat exchanger is analyzed to know the thermal behavior effects such as entropy generation minimization and exergetic efficiency. The analysis of first law which does not considers different irreversibilities such as transfer of heat, drop in fluid pressure and mass flow streams unbalance is possible from second law of thermodynamics studies. In this analysis the parameters which are considered are length to diameter dimensions of heat transfer equipment tube, fluid streams capacity ratio, Reynolds number of fluid and type of fully developed fluid flow. To understand the behavior of heat exchanger the heat capacity rate of heat exchanger’s maximum value is changed for both cases of hot stream and cold stream. Optimum heat exchanger geometrical dimension namely length-to-diameter ratio can be obtained from the second law analysis corresponding to lower total entropy generation and higher second law efficiency which leads to energy conservation. Accordingly, for the minimum entropy generation and maximum exergetic efficiency resulted, the optimum length-to-diameter ratio are obtained for different cases considered.

PERFORMANCE ANALYSIS OF MICROCHANNEL COUNTER FLOW HEAT EXCHANGER USING DIFFERENT NANOFLUIDS

2018 ◽  
Author(s):  
Bharath P ◽  
Doddamani Hithaish ◽  
Saravanan Venkatesh ◽  
C K Umesh
Keyword(s):  
Heat Exchanger ◽  
Performance Analysis ◽  
Counter Flow ◽  
Flow Heat

scholarly journals PENGARUH SUDUT LOUVERED STRIPS TERHADAP LAJU PERPINDAHAN PANAS PADA COUNTER FLOW HEAT EXCHANGER

2011 ◽  
Vol 8 (2) ◽  
Author(s):  
Nyoman Arya Wigraha
Keyword(s):  
Heat Exchanger ◽  
Performance Ratio ◽  
Counter Flow ◽  
Tube Heat Exchanger ◽  
Plain Tube ◽  
Flow Heat

Pengaruh turbulator Louvered strips terhadap laju perpindahan kalor dan faktor gesekan aliran turbulen pada double tube heat exchanger dapat memecah (partitioning) dan mengganggu (blockage) pola streamline dari fluida yang mengalir ke saluran pipa dalam (inner tube) sehingga mengakumulasi aliran turbulensi dan meningkatkan laju perpindahan kalor dalam pipa. Louvered strips memiliki variasi sudut serang (q = 15°, 25°, 30°) yang terpasang ditengah-tengah pipa bagian dalam dan searah aliran fluida masuk. Laju aliran fluida (air) panas di bagian pipa dalam diteliti dengan interval 400 lt/jam sampai 900 lt/jam dan laju aliran air dingin di bagian pipa luar konstan 900 lt/jam. Data hasil pengujian dari masing – masing sudut serang turbulator ini dibandingkan data tanpa turbulator (plain tube),  secara keseluruhan terjadi peningkatan laju perpindahan kalor sebesar 26 % sampai 58 % dari pada tanpa turbulator serta menghasilkan faktor gesekan dari 25 % sampai 40 %. Dengan performance ratio rata –rata tertinggi pada turbulator dengan sudut 30O sebesar 0,948.   Kata kunci:  Louvered strips, Heat Exchanger, Counter flow, turbulensi, faktor gesekan, turbulator, efektifitas

scholarly journals PENGARUH SUDUT LOUVERED STRIPS TERHADAP LAJU PERPINDAHAN PANAS PADA COUNTER FLOW HEAT EXCHANGER

2011 ◽  
Vol 8 (2) ◽  
Author(s):  
Nyoman Arya Wigraha
Keyword(s):  
Heat Exchanger ◽  
Performance Ratio ◽  
Counter Flow ◽  
Tube Heat Exchanger ◽  
Plain Tube ◽  
Flow Heat

Pengaruh turbulator Louvered strips terhadap laju perpindahan kalor dan faktor gesekan aliran turbulen pada double tube heat exchanger dapat memecah (partitioning) dan mengganggu (blockage) pola streamline dari fluida yang mengalir ke saluran pipa dalam (inner tube) sehingga mengakumulasi aliran turbulensi dan meningkatkan laju perpindahan kalor dalam pipa. Louvered strips memiliki variasi sudut serang (q = 15°, 25°, 30°) yang terpasang ditengah-tengah pipa bagian dalam dan searah aliran fluida masuk. Laju aliran fluida (air) panas di bagian pipa dalam diteliti dengan interval 400 lt/jam sampai 900 lt/jam dan laju aliran air dingin di bagian pipa luar konstan 900 lt/jam. Data hasil pengujian dari masing – masing sudut serang turbulator ini dibandingkan data tanpa turbulator (plain tube),  secara keseluruhan terjadi peningkatan laju perpindahan kalor sebesar 26 % sampai 58 % dari pada tanpa turbulator serta menghasilkan faktor gesekan dari 25 % sampai 40 %. Dengan performance ratio rata –rata tertinggi pada turbulator dengan sudut 30O sebesar 0,948.   Kata kunci:  Louvered strips, Heat Exchanger, Counter flow, turbulensi, faktor gesekan, turbulator, efektifitas

Second-Law Analysis on Wavy Plate Fin-and-Tube Heat Exchangers

1998 ◽  
Vol 120 (3) ◽  
pp. 797-800 ◽  
Author(s):  
W. W. Lin ◽  
D. J. Lee
Keyword(s):  
Entropy Generation ◽  
Operating Conditions ◽  
Generation Rate ◽  
Entropy Generation Rate ◽  
Second Law ◽  
Spanwise Direction ◽  
Minimum Entropy ◽  
Tube Heat Exchanger ◽  
Second Law Analysis ◽  
Minimum Entropy Generation

Second-law analysis on the herringbone wavy plate fin-and-tube heat exchanger was conducted on the basis of correlations of Nusselt number and friction factor proposed by Kim et al. (1997), from which the entropy generation rate was evaluated. Optimum Reynolds number and minimum entropy generation rate were found over different operating conditions. At a fixed heat duty, the in-line layout with a large tube spacing along streamwise direction was recommended. Furthermore, within the valid range of Kim et al.’s correlation, effects of the fin spacing and the tube spacing along spanwise direction on the second-law performance are insignificant.

Detailed Design Optimisation of Three-Fluid Parallel-Flow Plate-Fin Heat Exchanger Using Second Law Analysis

2020 ◽  
Author(s):  
Harpreet Kaur Aasi ◽  
Manish Mishra
Keyword(s):  
Heat Exchanger ◽  
Entropy Generation ◽  
Current Flow ◽  
Parallel Flow ◽  
Operating Conditions ◽  
Continuous Variables ◽  
Minimum Entropy ◽  
Louvered Fin ◽  
Counter Current Flow ◽  
Counter Current

Abstract Three-fluid compact heat exchanger of plate-fin type with parallel-flow configuration is optimised for the entropy generation. Four different types of plate fins (plain rectangular, offset strip, corrugated louvered and wavy fin) are embodied within heat exchanger for both co-current and counter-current flow arrangements have been selected for the study. Genetic algorithm is selected as an optimisation tool having apt in handling various continuous variables and discrete variables and the problems with complexities in the objective function as well as in constraints. Validation of the optimization model is carried out by comparing the results with that from experimental results, Particle swarm optimization (without heat duty constraint) and from graphical method (with heat duty constraint). It is observed that for a specified heat duty and given operating conditions corrugated louvered fin with counter-current flow arrangement offers the minimum entropy generation amongst all.

scholarly journals Second Law Analysis for the Experimental Performances of a Cold Heat Exchanger of a Stirling Refrigeration Machine

Entropy ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 215 ◽  
Author(s):  
Steve Djetel-Gothe ◽  
François Lanzetta ◽  
Sylvie Bégot
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Entropy Generation ◽  
Mass Flow ◽  
Hydraulic Diameter ◽  
Entropy Generation Rate ◽  
Second Law ◽  
Water Mixture ◽  
Fluid Friction ◽  
Refrigeration Machine

The second law of thermodynamics is applied to evaluate the influence of entropy generation on the performances of a cold heat exchanger of an experimental Stirling refrigeration machine by means of three factors: the entropy generation rate N S , the irreversibility distribution ratio ϕ and the Bejan number B e | N S based on a dimensionless entropy ratio that we introduced. These factors are investigated as functions of characteristic dimensions of the heat exchanger (hydraulic diameter and length), coolant mass flow and cold gas temperature. We have demonstrated the role of these factors on the thermal and fluid friction irreversibilities. The conclusions are derived from the behavior of the entropy generation factors concerning the heat transfer and fluid friction characteristics of a double-pipe type heat exchanger crossed by a coolant liquid (55/45 by mass ethylene glycol/water mixture) in the temperature range 240 K < TC < 300 K. The mathematical model of entropy generation includes experimental measurements of pressures, temperatures and coolant mass flow, and the characteristic dimensions of the heat exchanger. A large characteristic length and small hydraulic diameter generate large entropy production, especially at a low mean temperature, because the high value of the coolant liquid viscosity increases the fluid frictions. The model and experiments showed the dominance of heat transfer over viscous friction in the cold heat exchanger and B e | N S → 1 and ϕ → 0 for mass flow rates m ˙ → 0.1 kg.s−1.

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