Synthetic and Continuous Jets Impinging on a Circular Cylinder

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388998%3A_____%2F19%3A00505915" target="_blank" >RIV/61388998:_____/19:00505915 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/46747885:24210/19:00008176

Výsledek na webu

<a href="https://www.tandfonline.com/doi/full/10.1080/01457632.2018.1457245" target="_blank" >https://www.tandfonline.com/doi/full/10.1080/01457632.2018.1457245</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1080/01457632.2018.1457245" target="_blank" >10.1080/01457632.2018.1457245</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Synthetic and Continuous Jets Impinging on a Circular Cylinder

Popis výsledku v původním jazyce

Synthetic and continuous water jets impinging onto an electrically heated circular cylinder were experimentally investigated. The slot nozzle width was 0.36 mm, the cylinder diameter was 1.2 mm, and the cylinder-to-nozzle spacing related to the slot width was 5-21. Two optical methods were used: qualitative laser-induced fluorescence (LIF) visualization and laser Doppler vibrometry (LDV) measurements. Simultaneously with the optical experiments, the overall convective heat transfer from the circular cylinder was evaluated. The LDV quantified the velocity of the oscillating piezo-driven diaphragm at frequencies from 30 to 68 Hz. A majority of the study was performed at the near-resonant frequencies from 46 to 49 Hz. For all investigated jets, the Reynolds numbers based on the nozzle width ranged from 36 to 171. The LIF visualization revealed a dominant flow separation occurring on the windward cylinder side. This result is attributed to the effect of the miniscales, a relatively small ratio of the nozzle width to the cylinder diameter, and low Reynolds numbers. An increase in the Reynolds number changes the flow pattern from a steady jet-flow separation to a vortex shedding wake-flow regime. The heat transfer experiments were validated in a natural convection regime. An enhancement of the average Nusselt numbers by 4.2-6.2 times by means of the synthetic jets was quantified by comparison with the natural convection regime. A correlation for the average Nusselt number was proposed for both the continuous and synthetic jets.

Název v anglickém jazyce

Synthetic and Continuous Jets Impinging on a Circular Cylinder

Popis výsledku anglicky

Synthetic and continuous water jets impinging onto an electrically heated circular cylinder were experimentally investigated. The slot nozzle width was 0.36 mm, the cylinder diameter was 1.2 mm, and the cylinder-to-nozzle spacing related to the slot width was 5-21. Two optical methods were used: qualitative laser-induced fluorescence (LIF) visualization and laser Doppler vibrometry (LDV) measurements. Simultaneously with the optical experiments, the overall convective heat transfer from the circular cylinder was evaluated. The LDV quantified the velocity of the oscillating piezo-driven diaphragm at frequencies from 30 to 68 Hz. A majority of the study was performed at the near-resonant frequencies from 46 to 49 Hz. For all investigated jets, the Reynolds numbers based on the nozzle width ranged from 36 to 171. The LIF visualization revealed a dominant flow separation occurring on the windward cylinder side. This result is attributed to the effect of the miniscales, a relatively small ratio of the nozzle width to the cylinder diameter, and low Reynolds numbers. An increase in the Reynolds number changes the flow pattern from a steady jet-flow separation to a vortex shedding wake-flow regime. The heat transfer experiments were validated in a natural convection regime. An enhancement of the average Nusselt numbers by 4.2-6.2 times by means of the synthetic jets was quantified by comparison with the natural convection regime. A correlation for the average Nusselt number was proposed for both the continuous and synthetic jets.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20303 - Thermodynamics

Projekt

<a href="/cs/project/GA16-16596S" target="_blank" >GA16-16596S: Optimalizace generování pulzujících proudů v mechanice tekutin</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2019

Kód důvěrnosti údajů

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

Název periodika

Heat Transfer Engineering

ISSN

0145-7632

e-ISSN

—

Svazek periodika

40

Číslo periodika v rámci svazku

13-14

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

15

Strana od-do

1111-1125

Kód UT WoS článku

000472768800005

EID výsledku v databázi Scopus

2-s2.0-85045287583