A circular pipe of 25-mm outside diameter and 500-mm length is placed in an airstream at...
A circular pipe, with an outside diameter of 30 mm and a wall thickness of 4 mm, is held stationary in a stream of air for which T-30°C, F-1 atm , and V-25 m/s . The pipe, which is made of PVC, experiences cross-flow conditions in the moving air 1) The temperature at the inner surface of the pipe is maintained at 90°C. The outer surface of the pipe is smooth. Also, assume that steady-state conditions exist. Since the outer...
use dimensionless equations Problem 1 A pipe of outside diameter d=30 mm is exposed to the cross air flow at 20°C, velocity of the air is 5 m/s, and the temperature of the outside surface of the pipe is 80 °C. Determine: a) An average coefficient of heat transfer from outside surface of the pipe to the air. b) The heat flux exchanged per unit length of the pipe.
HEAT TRANSFER 2. A steam pipe, 12 m in length and 10 cm in diameter, is exposed to the cross flow of air at 5°C with the velocity of 25 km/h. The surface of the pipe is maintained at 75°C and its emissivity is estimated to be 0.8. The surrounding temperature is at 0°C. Determined the total heat loss from the pipe.
Annular aluminum fins of rectangular profile are attached to a circular tube having an outside diameter of 50 mm and an outer surface temperature of 400°C. The fins are mm thick and 20 mm long. The system is in ambient air at a temperature of 20°C, and the surface convection coefficient is 40 W/ mK. (a) What are the fin efficiency and effectiveness? (b) If there are 125 such fins per meter of tube length, what is the rate of...
A vertical tube has an outer diameter of 150 mm. The pipe is 4 m long and the outdoor temperature is 60 C. The room temperature is 20 oC. The heat transfer coefficient, ,for the air is 6 Calculate heat transfer / heat flow / heat output W from pipe to air. A vertical tube has an outer diameter of 150 mm. The pipe is 4 m long and the outdoor temperature is 60 oC. The room temperature is 20...
A steam main of 150 mm outside diameter containing wet steam at 28 bar is insulated with an inner layer of diatomaceous earth, 40 mm thick, and an outer layer of 85 % magnesia, 25 mm thick. The inside surface of the pipe is at the steam temperature, and the heat transfer coefficient for the outside surface of the lagging is 17 W/m2 K. The thermal conductivities of diatomaceous earth and 85 % magnesia are 0.09, and 0.06 40 ME...
A long cylindrical rod of diameter 220 mm with thermal conductivity 0.5 W/m-K expe riences uniform volumetric heat generation of 25,000 W/m3. The rod is encapsulated by a circular sleeve having 7 W/m K. The outer surface of the sleeve is exposed to cross flow of air at 25°C with a convection coefficient of 25 W/m2-K. Find the temperature at the interface between the rod and sleeve, and on the outer surface. an outer diameter of 410 mm and thermal...
(c) Steam flows a pipe of external diameter 30 mm, where the pipe outer surface temperature is 130oC. Circular annular fins (k = 180 W·m-1·K-1) of outer diameter 60 mm and thickness 1 mm are fitted tightly to the pipe. Heat is transferred by convection (h=10 W·m-2·K-1) to the surrounding air at 20oC. (i) Determine the efficiency of a single fin. (ii) Determine the heat transfer rate for a single fin. (8 marks) (6 marks) (iii) Determine the effectiveness of...
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...
G4 Problem Statement: Circular fins of uniform cross section, with diameter of 14 mm and length 70 mm are attached to the wall with surface temperature o C. The fin is made of material with thermal conductivity of 210 W/mk, and exposed to an ambient air condition of 24 °C and the convection heat transfer coefficient of 190 W/m2k. f 300 1- Plot the temperature variation for the following boundary conditions a- Infinitely long fin b- Adiabatic fin tip c-...