Dittus-Boelter equation used for the determination of heat transfer co-efficient is valid

Related MCQs

• For turbulent flow in a tube, the heat transfer co-efficient is obtained from the DittusBoelter correlation. If the tube diameter is halved and the flow rate is doubled, then the heat transfer co-efficient will change by a factor of
• Extended heat transfer surface like fins are used to increase the heat transfer rate. Fin efficiency is defined as the ratio of heat transferred across the fin surface to the theoretical heat transfer across an equal area held at the
• A dimensionless heat transfer coefficient which gives a measure of the ratio of the heat transfer rate to the rate at which heat would be conducted within the fluid under a temperature gradient is known as
• The average heat transfer co-efficient over the entire length of the plate (ha) and the local heat transfer co-efficient (hL), in case of heat transfer over a flat plate in laminar zone is related as
• A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0.8 W/m2 .°C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be
• The concept of overall coefficient of heat transfer is used in heat transfer problems of
• The concept of overall coefficient of heat transfer is used in case of heat transfer by
• The Sieder-Tate correlation for heat transfer in turbulent flow in pipe gives Nu α Re0.8 , where, Nu is the Nusselt number and Re is the Reynolds number for the flow. Assuming that this relation is valid, the heat transfer co-efficient varies with the pipe diameter (D) as
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