Comparison of Experimental Heat Transfer Coefficient with Qualitative Description of Classical Heat Transfer Coefficient at Low Heat Flux Conditions

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F46747885%3A24210%2F22%3A00010122" target="_blank" >RIV/46747885:24210/22:00010122 - isvavai.cz</a>

Výsledek na webu

<a href="http://https:/10.11159/ffhmt22.185" target="_blank" >http://https:/10.11159/ffhmt22.185</a>

DOI - Digital Object Identifier

—

Jazyk výsledku

angličtina

Název v původním jazyce

Comparison of Experimental Heat Transfer Coefficient with Qualitative Description of Classical Heat Transfer Coefficient at Low Heat Flux Conditions

Popis výsledku v původním jazyce

Due to complexities involved in experimental determination of heat transfer coefficient, diverse qualitative flow descriptions and maps have been proposed as the basis for theories and correlations. Interestingly, there have been several disagreements with the different qualitative descriptions and maps on their actual representation of heat transfer coefficient for certain regions of flow boiling processes. This study therefore seeks to experimentally investigate and compare the characteristics of heat transfer coefficient at low heat flux conditions with qualitative descriptions of heat transfer coefficient by different authors. In this study, R134a was the refrigerant used, heat fluxes from 4.6-8.5 kW/m2 and mass flux of 200-300 kg/m2s. The experimental heat transfer coefficient results were compared with Wojtan et al flow patterns map. In covering heat transfer coefficient over a wide range of vapor qualities, it was observed that, the qualitative descriptions proposed by different authors do not entirely validate the actual representation of heat transfer process within the experimental conditions studied. At vapor quality around zero (0), heat transfer coefficient rises to a peak and decreases to a local minimum before increasing as vapor quality increases and the flow pattern predicted for this region is slug flow. As vapor quality increased, the flow patterns observed were intermittent, annular, dryout and mist flow

Název v anglickém jazyce

Comparison of Experimental Heat Transfer Coefficient with Qualitative Description of Classical Heat Transfer Coefficient at Low Heat Flux Conditions

Popis výsledku anglicky

Due to complexities involved in experimental determination of heat transfer coefficient, diverse qualitative flow descriptions and maps have been proposed as the basis for theories and correlations. Interestingly, there have been several disagreements with the different qualitative descriptions and maps on their actual representation of heat transfer coefficient for certain regions of flow boiling processes. This study therefore seeks to experimentally investigate and compare the characteristics of heat transfer coefficient at low heat flux conditions with qualitative descriptions of heat transfer coefficient by different authors. In this study, R134a was the refrigerant used, heat fluxes from 4.6-8.5 kW/m2 and mass flux of 200-300 kg/m2s. The experimental heat transfer coefficient results were compared with Wojtan et al flow patterns map. In covering heat transfer coefficient over a wide range of vapor qualities, it was observed that, the qualitative descriptions proposed by different authors do not entirely validate the actual representation of heat transfer process within the experimental conditions studied. At vapor quality around zero (0), heat transfer coefficient rises to a peak and decreases to a local minimum before increasing as vapor quality increases and the flow pattern predicted for this region is slug flow. As vapor quality increased, the flow patterns observed were intermittent, annular, dryout and mist flow

Druh

A - Audiovizuální tvorba

CEP obor

—

OECD FORD obor

20301 - Mechanical engineering

Projekt

—

Návaznosti

S - Specificky vyzkum na vysokych skolach

Rok uplatnění

2022

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

ISBN

—

Místo vydání

—

Název nakladatele resp. objednatele

—

Verze

—

Identifikační číslo nosiče

—