Investigation of heat transfer between a horizontal tube and gas–solid fluidized bed.pdf

International Journal of Heat and Fluid Flow 29 (2008) 1504–1511 Contents lists available at ScienceDirect International Journal of Heat and Fluid Flow journal homepage: www.else /locate/ijhff Investigation of heat transfer between a horizontal tube and gas–solid fluidized bed Nima Masoumifard, Navid Mostoufi *, Ali-Asghar Hamidi, Rahmat Sotudeh-Gharebagh Multiphase Systems Research Laboratory, Department of Chemical Engineering, University of Tehran, P.O. Box 11155-4563, Tehran, Iran a r t i c l e i n f o a b s t r a c t Article history: Experiments have been carried out in a fluidized bed in order to verify the influence of the axial position, Received 22 March 2008 particle diameter and the superficial gas velocity on the heat transfer coefficient from a small horizontal Received in revised form 14 June 2008 tube (Dt = 8 mm) immersed in the fluidized bed. The solid particles used were 280, 490 and 750 lm diam- Accepted 26 June 2008 eter sand particles, fluidized by air. The experimental results showed that the heat transfer coefficient is Available online 12 August 2008 increased with increasing the gas velocity, up to a maximum, and then decreases with a slight slope. The heat transfer coefficient was found to decrease by increasing the particle size. The probe position had less Keywords: influence on the heat transfer coefficients. In order to predict the heat transfer coefficient from the fluid- Fluidized bed Heat transfer co