In this paper a new method for determining heat transfer coefficients using a gradient method has been developed. To verify accuracy of the proposed method vertical isothermal heating plate with natural convection mechanism has been examined. This configuration was deliberately chosen, because of the fact that such case is historically the earliest and most thoroughly studied and its rich scientific documentation - the most reliable. New method is based on temperature field visualization made in perpendicular plane to the heating surface of the plate using infrared camera. Because the camera does not record temperature of air itself but the surface only, therefore plastic mesh with low thermal conductivity has been used as a detector. Temperature of each mesh cell, placed perpendicular to the vertical heating surface and rinsed with convection stream of heated air could be already recorded by infrared camera. In the same time using IR camera surface of heating plate has been measured. By numerical processing of the results matrix temperature gradient on the surface ∂T/∂x│x=0, local heat transfer coefficients αy, and local values of Nusselt number Nuy, can be calculated. After integration the average Nusselt number for entire plate can be calculated. Obtained relation characteristic numbers Nu = 0.647 Ra 0.236 (R2 = 0.943), has a good correlation with literature reports and proves usefulness of the method.
Autorzy
- Hubert Denda link otwiera się w nowej karcie ,
- prof. dr hab. inż. Witold Lewandowski link otwiera się w nowej karcie ,
- dr hab. inż. Michał Ryms link otwiera się w nowej karcie ,
- Patrycja Wcisło-Kucharek link otwiera się w nowej karcie ,
- prof. dr hab. Ewa Klugmann-Radziemska link otwiera się w nowej karcie
Informacje dodatkowe
- DOI
- Cyfrowy identyfikator dokumentu elektronicznego link otwiera się w nowej karcie 10.1051/matecconf/20141803002
- Kategoria
- Aktywność konferencyjna
- Typ
- materiały konferencyjne indeksowane w Web of Science
- Język
- angielski
- Rok wydania
- 2014