- Author
- Kapoor, K. | Jaluria, Y.
- Title
- Mixed Convective Heat Transfer Characteristics of a Downward Turning Buoyant Ceiling Jet.
- Coporate
- Rutgers, State University of New Jersey, New Brunswick
- Sponsor
- National Institute of Standards and Technology, Gaithersburg, MD
- Contract
- NIST-GRANT-60NANB7D0743
- Book or Conf
- American Society of Mechanical Engineers (ASME). National Heat Transfer Conference, 28th. Mixed Convection Heat Transfer, 1991. HTD-Vol. 163. July 28-31, 1991, Am. Soc. of Mechanical Engineers, New York, NY, Minneapolis, MN, Pepper, D. W.; Armaly, B. F.; Ebadian, M. A.; Oosthuizen, P. H., Editors, 9-17 p., 1991
- Keywords
- ceiling jets | convective heat transfer
- Abstract
- An experimental investigation has been carried out on the mixed convective heat transfer characteristics of a buoyant ceiling jet turning downward at a corner. Such flows are frequently encountered in buoyancy driven transport in enclosed regions, such as those associated with thermal energy storage problems and enclosure fires. However, very little work has been done on the basic heat transfer mechanisms in such flows, particularly on the local heat flux distributions over the ceiling and the vertical wall near the corner. In this study, a two-dimensional horizontal jet of heated air is discharged adjacent to the underside of an isothermal horizontal plate whose other end is attached to an isothermal vertical plate, making a right angle corner with it. The distance between the jet discharge and the corner could be varied. Extensive heat flux measurements were carried out for different inflow conditions of the jet. The variation of the local heat transfer rate along the ceiling and the vertical wall shows a minimum followed by a recovery, as the flow turns at the corner. The average Nusselt numbers for the horizontal surface and the vertical walls are obtained as functions of the mixed convection parameter Gr/Re² which is also known as the Richardson number Ri of the discharged ceiling jet. The total heat transfer rate to the isothermal ceiling and the vertical wall by the jet flow is also obtained. The study brings out several basic considerations in the thermal transport from a buoyant jet to the isothermal surface over which it flows, including the effects of opposing buoyancy for the vertical wall.