Mao Takeyama (Avtor), Matevž Zupančič (Avtor), Tomoaki Kunugi (Avtor)

Povzetek

To clear the effects of the hydrodynamic interactions among neighboring vapor bubbles on the saturated pool boiling heat transfer, artificial nucleation sites with several cavity arrangements were manufactured on the substrate surface and measured liquid temperatures near heated substrate by a miniature thermocouple probe with 10 kHz. The surface temperature of heated substrate was measured by an infrared camera with 1 kHz and bubble dynamics were simultaneously visualized by a high-speed video camera with 5 kHz and 10 kHz, respectively. The liquid temperature fluctuations, measured with micro thermocouple 100 %m and 10 %m above the substrate surface, were compared among each other and with the transient temperature fields obtained through IR measurements. Results showed that the hydrodynamic interaction among neighboring bubbles causes the liquid convection, that was only detected 100 %m above the boiling surface. Generally, the degree of liquid temperature fluctuations at 10 %m height and different arrangements of nucleation sites was under 1 K. Here the superheated sublayer in the vicinity of the boiling surface was generally not affected by the convection. Only when the coalescence from two neighboring nucleation sites occurred and the liquid-vapor interface nearly reached the substrate, a steep temperature drop over 2 K was detected. It was concluded that the viscous sublayer stably exists during boiling of water in lower heat flux conditions. To enhance the convective heat transfer in nucleate boiling, coalesced bubble needs to peel off the viscous sublayer during its deformation. Based on the measurements in this study, this peel-off effect only happens when the coalescence point is less than 1 mm above the heated surface.

Ključne besede

nucleate boiling;bubble coalescence;superheated sublayer;convection effect;liquid temperature measurement;substrate temperature measurement;

Podatki

Jezik: Angleški jezik
Leto izida:
Tipologija: 1.01 - Izvirni znanstveni članek
Organizacija: UL FS - Fakulteta za strojništvo
UDK: 536.24
COBISS: 66639875 Povezava se bo odprla v novem oknu
ISSN: 0894-1777
Št. ogledov: 249
Št. prenosov: 19
Ocena: 0 (0 glasov)
Metapodatki: JSON JSON-RDF JSON-LD TURTLE N-TRIPLES XML RDFA MICRODATA DC-XML DC-RDF RDF

Ostali podatki

Sekundarni jezik: Slovenski jezik
Sekundarne ključne besede: mehurčkasto vrenje;koalescence mehurčkov;pregreta plast;konvektivni učinki;meritve temperature v kapljevini;meritve temperature na površini;
Vrsta dela (COBISS): Članek v reviji
Konec prepovedi (OpenAIRE): 2023-10-01
Strani: str. 1-11
Zvezek: ǂVol. ǂ128
Čas izdaje: 1 Oct. 2021
DOI: 10.1016/j.expthermflusci.2021.110449
ID: 13032313