A grain dryer consists of a long semicircular duct of radius R = 1 m. One-half of
Question:
A grain dryer consists of a long semicircular duct of radius R = 1 m. One-half of the base surface consists of an electrically heated plate of emissivity ɛp = 0.8, while the other half supports the grain to be dried, which has an emissivity of ɛg = 0.9. In a batch drying process for which the temperature of the grain is Tg = 330 K, 2.50 kg of water are to be removed per meter of duct length over a 1-hour period.
(a) Neglecting convection heat transfer, determine the required temperature Tp of the heater plate.
(b) If the water vapor is swept from the duct by the flow of dry air, what convection mass transfer coefficient hm must be maintained by the flow?
(c) If the air is at 300 K, is the assumption of negligible convection justified?
Step by Step Answer:
a To calculate the required temperature Tp of the heater plate we need to balance the radiant h...View the full answer
Fundamentals of Heat and Mass Transfer
ISBN: 978-0471457282
6th Edition
Authors: Incropera, Dewitt, Bergman, Lavine
