The Size Effect of Heat-Transfer Surfaces on Boiling

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26210%2F16%3APU116772" target="_blank" >RIV/00216305:26210/16:PU116772 - isvavai.cz</a>

Výsledek na webu

<a href="http://dx.doi.org/10.17222/mit.2015.245" target="_blank" >http://dx.doi.org/10.17222/mit.2015.245</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.17222/mit.2015.245" target="_blank" >10.17222/mit.2015.245</a>

Jazyk výsledku

angličtina

Název v původním jazyce

The Size Effect of Heat-Transfer Surfaces on Boiling

Popis výsledku v původním jazyce

A sprinkled tube bundle is frequently used in technology processes where an increase or decrease of a liquid temperature in a very low-pressure environment is required. Phase transitions of the liquid very often occur at low temperatures at pressures ranging in the thousands of pascals, which enhances the heat transfer. This paper focuses on the issue of a heat-transfer coefficient that is experimentally examined at the surface of a tube bundle. The tube is located in a low-pressure chamber where the vacuum is generated using an exhauster via an ejector. The tube consists of smooth copper tubes of 12 mm diameter placed horizontally one above another. Heating water flows in the bundle from the bottom towards the top at an average input temperature of approximately 40 °C and an average flow rate of approximately 7.2 L/min. A falling film liquid at an initial temperature of approximately 15 °C at an initial tested pressure of approximately 97 kPa (atmospheric pressure) is sprinkled onto the tubes’ surface. Afterwards, the pressure in the chamber is gradually decreased. When reaching the minimum pressure of approximately 3 kPa (abs) the water partially evaporates at the lower part of the bundle. Consequently, the influence of the falling film liquid temperature increase is tested. This gradually leads to the boiling of water in a significant part of the bundle and the residual cooling liquid that drops back to the bottom of the vessel is almost not heated anymore. In this paper we present the influences of the size of the heat-transfer surfaces.

Název v anglickém jazyce

The Size Effect of Heat-Transfer Surfaces on Boiling

Popis výsledku anglicky

A sprinkled tube bundle is frequently used in technology processes where an increase or decrease of a liquid temperature in a very low-pressure environment is required. Phase transitions of the liquid very often occur at low temperatures at pressures ranging in the thousands of pascals, which enhances the heat transfer. This paper focuses on the issue of a heat-transfer coefficient that is experimentally examined at the surface of a tube bundle. The tube is located in a low-pressure chamber where the vacuum is generated using an exhauster via an ejector. The tube consists of smooth copper tubes of 12 mm diameter placed horizontally one above another. Heating water flows in the bundle from the bottom towards the top at an average input temperature of approximately 40 °C and an average flow rate of approximately 7.2 L/min. A falling film liquid at an initial temperature of approximately 15 °C at an initial tested pressure of approximately 97 kPa (atmospheric pressure) is sprinkled onto the tubes’ surface. Afterwards, the pressure in the chamber is gradually decreased. When reaching the minimum pressure of approximately 3 kPa (abs) the water partially evaporates at the lower part of the bundle. Consequently, the influence of the falling film liquid temperature increase is tested. This gradually leads to the boiling of water in a significant part of the bundle and the residual cooling liquid that drops back to the bottom of the vessel is almost not heated anymore. In this paper we present the influences of the size of the heat-transfer surfaces.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20704 - Energy and fuels

Projekt

<a href="/cs/project/LO1202" target="_blank" >LO1202: NETME CENTRE PLUS</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2016

Kód důvěrnosti údajů

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

Název periodika

Materiali in tehnologije

ISSN

1580-2949

e-ISSN

1580-3414

Svazek periodika

50

Číslo periodika v rámci svazku

6

Stát vydavatele periodika

SI - Slovinská republika

Počet stran výsledku

6

Strana od-do

939-944

Kód UT WoS článku

000391224300016

EID výsledku v databázi Scopus

2-s2.0-85008413109