


1. Water flows over a cylinder perpendicular to its axis (in cross flow) at 3 m/s....
heat and mass transfer
(20 points) Air at 25°C cools a 2170 cylindrical battery (with a diameter of 21 mm and a length of 70 mm) with a cross flow velocity of 6 m/s. a) Determine the average convective heat transfer coefficient. (b) If the battery's internal heat generation is 5W and its thermal conductivity is 0.6 w/m-k, the determine the battery surface temperature and the maximum temperature in battery
(20 points) Air at 25°C cools a 2170 cylindrical battery...
Problem 3 (20 points) A cross-flow heat exchanger consists of a bundle of 32 tubes in a long duct. Hot water at 150°C and a mean velocity of 0.5 m/s enters the tubes having inner and outer diameters of 10.2mm and 12.5mm and has to be cooled to 136°C. The tubes are made of steel of thermal conductivity k-40 W/m.K. Air at 10°c enters the exchanger (unfinned) with a volumetric flow rate of 1.0 m3/s. The convective heat transfer coefficient...
Oil of unknown properties is heated in a shell-and-tube heat exchanger with one shell pass and 20 tube passes. The oil flows through the shell, and hot water flows inside the single copper tube that has an inner diameter of 20 mm, a wall thickness of 2 mm, and a length of 3 m per pass. The water enters at 360 K at a mass flow rate of 0.2 kg/s and leaves at 300 K. The inlet and outlet temperatures...
Q3. A very long horizontal cylinder of Unobtainium, of diameter 100 mm, is initially at a uniform temperature of 500 K. The cylinder is cooled by a fan. The fan blow airs, with a temperature of 300 K, over the cylinder at a velocity of 6 m/s in a direction perpendicular to the axis of the cylinder. Calculate a) the average convective heat transfer coefficient at the beginning of the cooling process when the initial temperature of the cylinder is...
Water at an average velocity of 3.5 m/s flows through a 5-m-long stainless steel tube (k = 14.2 W/m °C) in a boiler. The inner and outer diameters of the tube are Di = 1.0 cm and Do = 1.4 cm, respectively. If the convection heat transfer coefficient at the outer surface of the tube where boiling is taking place is ho = 8400 W/m2 • °C, determine product of the overall heat transfer coefficient Ui by the inner surface...
can you solve only last 4
questions
Q3. Oil of unknown properties is heated in a shell-and-tube heat exchanger with one shell pass and 20 tube passes. The oil flows through the shell, and hot water flows inside the single copper tube that has an inner diameter of 20 mm, a wall thickness of 2 mm, and a length of 3 m per pass. The water enters at 360 Kat a mass flow rate of 0.2 kg/s and leaves at...
Fluid enters a tube with a flow rate of 0.023 kg/s and an inlet temperature of 20°C. The tube, which has a length of 6 mand diameter of 15 mm, has a surface temperature of 30°C. Determine the heat transfer rate to the fluid if it is water, in W. Evaluate the properties of water at 300 K. Obtain the Nusselt number using the Baehr and Stephan recommended correlation. 9 w nin
Water is to be heated from 10 °C to 83 °C as it flows through a 0.015 m-internal-diameter, 13-m-long tube. The tube is equipped with an electric resistance heater, which provides uniform heating throughout the surface of the tube. The outer surface of the heater is well insulated, so that in steady operation all the heat generated in the heater is transferred to the water in the tube. The system provides hot water at a rate of 5 L/min Assumelp...
Problem 8.023 Fluid enters a tube with a flow rate of 0.017 kg/s and an inlet temperature of 20°C. The tube, which has a length of 6 m and diameter of 15 mm, has a surface temperature of 30°C. Determine the heat transfer rate to the fluid if it is water, in W. Evaluate the properties of water at 300 K. Obtain the Nusselt number using the Baehr and Stephan recommended correlation 9 Physical Properties Mathematical Functions the tolerance is...
An automobile radiator may be viewed as a cross-flow heat exchanger with both fluids unmixed. Water, which has a flow rate of 0.045 kg/s, enters the radiator at 400 K and is to leave at 330 K. The water is cooled by air that enters at 0.75 kg/s and 300 K. If the overall heat transfer coefficient is 220 W/m2.K, what is the required heat transfer surface area, in mº? Assume that T =320 K when evaluating the properties of...