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Estimation of Thermal and Hydraulic Characteristics of Compact Brazed Plate Heat Exchangers

Gullapalli, Vijaya Sekhar LU (2013)
Abstract (Swedish)
Popular Abstract in Swedish

Lödda kompakta plattvärmeväxlare används i stor utsträckning i kyl – och värmepumpanläggningar samt luftkonditioneringsanläggningar.

Såväl enfasvärmeutbyte, dvs värmeutbyte mellan två vätskor, som fasomvandling genom kondensation och förångning är viktiga

tillämpningsområden. Apparaterna användes inom industri, hushåll, samhälleliga inrättningar mm.

Prestandan för olika plattvärmeväxlare har traditionellt bestämts genom experimentella undersökningar av värmeöverföring och tryckfall i

speciella testriggar eller laboratorier hos de tillverkande företagen.

För att göra ingenjörsarbetet med produktutveckling, design samt test av innovativa idéer effektivt... (More)
Popular Abstract in Swedish

Lödda kompakta plattvärmeväxlare används i stor utsträckning i kyl – och värmepumpanläggningar samt luftkonditioneringsanläggningar.

Såväl enfasvärmeutbyte, dvs värmeutbyte mellan två vätskor, som fasomvandling genom kondensation och förångning är viktiga

tillämpningsområden. Apparaterna användes inom industri, hushåll, samhälleliga inrättningar mm.

Prestandan för olika plattvärmeväxlare har traditionellt bestämts genom experimentella undersökningar av värmeöverföring och tryckfall i

speciella testriggar eller laboratorier hos de tillverkande företagen.

För att göra ingenjörsarbetet med produktutveckling, design samt test av innovativa idéer effektivt krävs datorbaserade beräkningsmetoder av

olika slag. Vijayas avhandling handlar i huvudsak om detta och han har utvecklat beräkningsverktyg och beräkningsmetoder som är

tillämpbara för dessa ändamål.

Användningen av avancerade och moderna beräkningsmetoder (CFD) baserade på lösning av partiella differentialekvationer (vilka

matematiskt beskriver värmeöverföringen och strömningen) utvärderas ingående genom studier av inverkan av ett flertal parametrar såsom

turbulensmodeller, randvillkor och geometrisk upplösning mm. Rekommendationer fastläggs.

En robust enklare metodik för prestandaberäkning har utvecklats för valet av lödd plattvärmeväxlare. Tryck-entalpi metoden utgör grunden.

För att möjliggöra att den utvecklade metodiken kan integreras med andra simuleringsverktyg har speciella subrutiner utvecklats för

beräkning av värmeövergångskoefficienter och köldmediers termiska egenskaper.

Metoder har också utvecklats för utvärdering av experimentella mätningar för såväl enfas som fasomvandlingsprocesser.

Noggrannhetsaspekter i olika metoder för uppskattning av termiska prestanda ventileras också. (Less)
Abstract
This thesis work presents various performance estimation methods of compact brazed plate

heat exchangers (BPHE) operating in single phase, condenser, evaporator, cascaded and

transcritical applications. Such methods play a vital role in development of heat exchanger

selection software and during geometry parameter estimation in the new product development

process.

The suitability of employing commercial computational fluid dynamics (CFD) codes for

estimating single phase thermal and hydraulic performance is investigated. Parametric studies

are conducted on geometries of single phase fluid sections to isolate and quantify the

influence of individual geometric... (More)
This thesis work presents various performance estimation methods of compact brazed plate

heat exchangers (BPHE) operating in single phase, condenser, evaporator, cascaded and

transcritical applications. Such methods play a vital role in development of heat exchanger

selection software and during geometry parameter estimation in the new product development

process.

The suitability of employing commercial computational fluid dynamics (CFD) codes for

estimating single phase thermal and hydraulic performance is investigated. Parametric studies

are conducted on geometries of single phase fluid sections to isolate and quantify the

influence of individual geometric parameters. The influence of mesh characteristics, choice of

boundary conditions and turbulent flow modeling on the accuracy of the thermal and

hydraulic predictions is presented. Benefits of simulation of fluid flow in entire channels and

characteristics of channel flow for different geometric patterns are also presented.

A computationally light, general, robust and continuous rating calculation method is

developed for implementation in BPHE selection software. The pressure-enthalpy based

method provides a generic rating core for various types of applications and provides extensive

post processing information of the heat transfer process. General single phase thermal and

hydraulic empirical correlations are developed as functions of plate geometric parameters.

For facilitating better integration of the developed calculation method with other refrigeration

system simulation software, first or higher order continuity is maintained in the sub-routines

used for calculating local heat transfer coefficients and refrigerant properties. A new finite

grid interpolation method is developed for fast and accurate retrieval of refrigerant properties.

The developed method is currently implemented in SSPG7 (BPHE selection software of

SWEP International AB) for supporting transcritical CO2 calculations and cascaded heat

exchanger calculations.

Additionally, the methods developed for single phase and two phase test data evaluation

based on meta-heuristic optimization routines is also presented. The application and results of

using the developed rating models for various types of calculations is summarized. Other

topics such as influence of variable fluid properties on BPHE rating calculations, influence of

multi-pass flow arrangement on lumped BPHE rating calculations are briefly presented. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Dr Wadekar, Vishwas, Aspen Technology, Great Britain
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Brazed plate heat exchangers, CFD, heat transfer, pressure drop, heat exchanger selection software, transcritical-CO2 calculations, heat exchanger rating, evaporation, condensation, refrigerant properties, discretized calculations
pages
156 pages
publisher
Department of Energy Sciences, Lund University
defense location
Room E:B, in the E-building, Ole Römers väg 3, Lund University Faculty of Engineering
defense date
2013-06-13 13:15
ISBN
978-91-7473-565-9
language
English
LU publication?
yes
id
e881a11f-f55d-479f-bb39-efb462c120ec (old id 3799250)
date added to LUP
2013-05-23 12:35:28
date last changed
2016-09-19 08:45:11
@phdthesis{e881a11f-f55d-479f-bb39-efb462c120ec,
  abstract     = {This thesis work presents various performance estimation methods of compact brazed plate<br/><br>
heat exchangers (BPHE) operating in single phase, condenser, evaporator, cascaded and<br/><br>
transcritical applications. Such methods play a vital role in development of heat exchanger<br/><br>
selection software and during geometry parameter estimation in the new product development<br/><br>
process.<br/><br>
The suitability of employing commercial computational fluid dynamics (CFD) codes for<br/><br>
estimating single phase thermal and hydraulic performance is investigated. Parametric studies<br/><br>
are conducted on geometries of single phase fluid sections to isolate and quantify the<br/><br>
influence of individual geometric parameters. The influence of mesh characteristics, choice of<br/><br>
boundary conditions and turbulent flow modeling on the accuracy of the thermal and<br/><br>
hydraulic predictions is presented. Benefits of simulation of fluid flow in entire channels and<br/><br>
characteristics of channel flow for different geometric patterns are also presented.<br/><br>
A computationally light, general, robust and continuous rating calculation method is<br/><br>
developed for implementation in BPHE selection software. The pressure-enthalpy based<br/><br>
method provides a generic rating core for various types of applications and provides extensive<br/><br>
post processing information of the heat transfer process. General single phase thermal and<br/><br>
hydraulic empirical correlations are developed as functions of plate geometric parameters.<br/><br>
For facilitating better integration of the developed calculation method with other refrigeration<br/><br>
system simulation software, first or higher order continuity is maintained in the sub-routines<br/><br>
used for calculating local heat transfer coefficients and refrigerant properties. A new finite<br/><br>
grid interpolation method is developed for fast and accurate retrieval of refrigerant properties.<br/><br>
The developed method is currently implemented in SSPG7 (BPHE selection software of<br/><br>
SWEP International AB) for supporting transcritical CO2 calculations and cascaded heat<br/><br>
exchanger calculations.<br/><br>
Additionally, the methods developed for single phase and two phase test data evaluation<br/><br>
based on meta-heuristic optimization routines is also presented. The application and results of<br/><br>
using the developed rating models for various types of calculations is summarized. Other<br/><br>
topics such as influence of variable fluid properties on BPHE rating calculations, influence of<br/><br>
multi-pass flow arrangement on lumped BPHE rating calculations are briefly presented.},
  author       = {Gullapalli, Vijaya Sekhar},
  isbn         = {978-91-7473-565-9},
  keyword      = {Brazed plate heat exchangers,CFD,heat transfer,pressure drop,heat exchanger selection software,transcritical-CO2 calculations,heat exchanger rating,evaporation,condensation,refrigerant properties,discretized calculations},
  language     = {eng},
  pages        = {156},
  publisher    = {Department of Energy Sciences, Lund University},
  school       = {Lund University},
  title        = {Estimation of Thermal and Hydraulic Characteristics of Compact Brazed Plate Heat Exchangers},
  year         = {2013},
}