Thermal streak spacing in fully developed duct flow with different Reynolds and Prandtl numbers

Sharma, Mohit Pramod (avtor), Tiselj, Iztok (avtor), Kren, Jan (avtor), Mikuž, Blaž (avtor), Cizelj, Leon (avtor)

The present study investigates the behaviour of thermal streaks on a heated foil which is cooled with turbulent flow in a square duct channel. Real-time infrared thermography is used to visualize and measure the spacing between the thermal streaks. A stainless-steel foil with a thickness of 25 microns is cooled by water. The experiments were performed in a range of Reynolds numbers from 5000 to 20000 and Prandtl numbers from 3 to 7. The mean temperature, root-mean-square of temperature and autocorrelation function have been calculated and used to measure the average thermal streak spacing and power spectra in the spanwise and streamwise directions. The root mean square temperature was 0.3 °C to 0.5 °C which corresponds to roughly 10% of the mean temperature difference between foil and water. The uncertainty in mean temperature difference and root mean square temperature was around 5% and 10%, respectively. The measured thermal streak spacing was 100 wall unit to 180 wall unit under the present experimental range. The uncertainty in measured thermal streak spacing was around 2.5%. The effects of Reynolds number, Prandtl number and heat flux on the thermal streak spacing and also on the statistics of the temperature field have been presented and discussed in this paper. A new correlation has been proposed to predict the dimensionless thermal streak spacing. The error in the prediction is estimated within ± 15 %.

• Jezik: Angleški jezik
• Ključne besede: thermal streaks, thermal streak spacing, Reynolds number, Prandtl number, heat flux
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: FMF - Fakulteta za matematiko in fiziko
• Status publikacije: Objavljeno
• Različica publikacije: Objavljena publikacija
• Leto izida: 2023
• Št. strani: Str. 2105–2116
• Številčenje: Vol. 59, iss. 11
• PID: 20.500.12556/RUL-152539
• UDK: 621.039
• ISSN pri članku: 1432-1181
• DOI: 10.1007/s00231-023-03399-z
• COBISS.SI-ID: 159282435
• Datum objave v RUL: 27.11.2023

Gradivo je del revije

• Naslov: Heat and mass transfer
• Skrajšan naslov: Heat mass transf.
• Založnik: Springer Nature
• ISSN: 1432-1181
• COBISS.SI-ID: 512810265

Licence

• Licenca: CC BY 4.0, Creative Commons Priznanje avtorstva 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by/4.0/deed.sl
• Opis: To je standardna licenca Creative Commons, ki daje uporabnikom največ možnosti za nadaljnjo uporabo dela, pri čemer morajo navesti avtorja.

Projekti

• Financer: ARRS - Agencija za raziskovalno dejavnost Republike Slovenije
• Številka projekta: L2-9210
• Naslov: Raziskave turbulentnega prenosa toplote v kanalu z naprednimi eksperimentalnimi in računskimi metodami

• Financer: ARRS - Agencija za raziskovalno dejavnost Republike Slovenije
• Številka projekta: P2-0026
• Naslov: Reaktorska tehnika