Waste heat of exhaust hot air from a manufacturing process may be recovered by passing water through a thin-walled tube of 1.00 cm diameter as shown. Assume the temperature of the hot air is 177℃ in cross flow with a velocity of 20 m/s over the tube. The inlet and outlet temperature of water are 20C and 60 C, rospectively, and the ilow rate is 0.2 k/s. Deiemine (a) the total heat transfer rate from air to water, (b) The...
A concentric tube heat exchanger for cooling lubricating oil
consists of a thin-walled inner tube of 25 mm diameter carrying
water and an outer tube of 45 mm diameter carrying the oil. The
exchanger operates in countercurrent flow with an overall heat
transfer coefficient of 55 W/m2 K and the tabulated average
properties given below. Mass flow rates of oil and water are both
0.1 kg/s, oil enters the exchanger at 100°C, and water enters the
exchanger at 30°C. (a)...
A concentric tube heat exchanger of length L = 2 m is used to thermally process a pharmaceutical product flowing at a mean velocity of u_m,c = 0.1 m/s with an inlet temperature of T_c,i = 20 degree C. The inner tube of diameter D_i = 10 mm is thin walled, and the exterior of the outer tube (D_0 = 20 mm) is well insulated. Water flows in the annular region between the tubes at a mean velocity of u_m,h...
25 PRR HEAT TRANSFER NAME: UNIT SIX AND SEVEN EXCHANGERS BOILING AND CONDENSATION, He- Solve the following problems: 1. In a gas-faired boiler, water is boiler at 150 C by hot gases flowing through 59 m long, 5 cm outer diameter mechanically polished stailess-stell pipes submerged in water, If the outer surface temperature of the pipes is 180 °C. determine (a) the rate of heat transfer from the hot gases to water. (b) the rate of evaporation, (c) the ratio...
Water enters a 20-mm tube at 27°C with a flow rate of 450 kg/h. The rate of heat transfer from the tube wall to the fluid is given as q5'(W/m) - a x, where the coefficient a is 20 W/m2 and x (m) is the axial distance from the tube entrance. (a) Beginning with a properly defined differential control volume in the tube, derive an expression for the temperature distribution T m(x) of the water. Use this expression to determine...
Problem 3: (35pts) Atmospheric air enters the heated section of a circular tube at a flow rate of 0.005 kg/s and a temperature of 30°C. The tube is of diameter D =60mm, and fully developed conditions with h = 30W/m2K exist over the entire length of L-4m. Take cp-1015 /kg.K 2 (a) (10pts) For the case of uniform surface heat flux at q"-1000W/m, determine the total heat transfer rate q and the mean temperature of the air leaving the tube...
An organic liquid is heated from 20°C to 40°C by hot water in a 1:1 pass shell-and- tube heat exchanger in counter-current flow. The inlet temperature of the water stream is 85oC and flows in the shell side. The organic liquid flows through a bundle of 200 tubes of outside diameter 21 mm with a wall thickness of 2 mm. The flows of the organic liquid and water are 40 kg s and 15 kg s1, respectively (a) Calculate the...
A) Determine the convection
heat transfer coefficient for the flow of air.
[W/m2·°C]
B) Determine the convection heat transfer coefficient for water.
[W/m2·°C]
The velocity of the fluid is 9 m/s in an 8-cm diameter and 7-m-long tube when the tube is subjected to uniform heat flux from all surfaces. Use fluid properties at 25°C. Water or Air D 8 cm L=7 m Given: The properties of air at 25°C are: k 0.02551 W/m."C v 1.562 10-5 m2/s Pr =...
the examinatiU to Heat Transfer" by Frank P. Incropera and Bavid F. Air entering a circular stainless steel tube D 50 mm outside diameter by d 45 mm inside diameter by L 5 m long atTa 20 C is heated by saturated steam at T100 c through which the tube passes. The thermal conductivity of the stainless steel tube kss .. 16.3 w/m° ? and the heat transfer coefficient at the interface between the tube and the steam h. 5000...
Problem 1. (30 points) A double-pipe heat exchanger is used to condense steam at 7370 N/m2. Water at an average bulk temperature of 10°C flows at 2.50 m/s through the inner pipe. which is made of copper and has a 2.54-cm ID and a 3.05-cm OD. Steam at its saturation temperature flows in the annulus formed between the outer surface of the inner pipe and an outer pipe of 5.08-cm-ID. The average heat transfer coefficient of the condensing steam is...