Chapter 4, Problem 4.20P

In a thermal power plant, a horizontal copper pipe of "D" diameter, "L" length and thickness 1.9 cm enters into the boiler that has the thermal conductivity as 0.37 W/mK. The boiler is maintained at 102 °C and temperature of the water that flows inside the pipe is at 34°C. If the energy transfer (Q) is 100735 kJ in 7 hours. Determine the Heat transfer rate, Surface area of the pipe and Diameter & Length of the pipe, if D = 0.015 L .

Energy transfer by conduction is primarily restricted to liquids fluids gases solids   Which is correct?

Q#01: Write a short note on the following: What are the best possible solutions to increase the heat transfer rate of a body? Which material will transfer more heat? Either a material with thermal conductivity ? = 121 or ? = 22  . Justify your answer. Explain the Fouling phenomenon. What is the effect of fouling on heat transfer rate.

A 10-cm diameter pipe is covered by 2 layers of lagging. The insidelayer is 4 cm thick and has a coefficient of thermal conductivity of 0.08W/m-K. The outside layer is 3cm thick and has a coefficient of thermalconductivity of 0.15 W/m-K. The steam main conveys steam apressure of 1.7 MPa with 25 C superheat. The outside temperature ofthe lagging is 27 C. If the steam main is 30 m long, determine theinterface temperature of the lagging and overall coefficient of heattransfer based on outside area.

In a thermal power plant, a horizontal copper pipe of "D" diameter, "L" length and thickness 1.7 cm enters into the boiler that has the thermal conductivity as 0.3 W/mK. The boiler is maintained at 107degreeC and temperature of the water that flows inside the pipe is at 31degreeC. If the energy transfer (Q) is 124925 kJ in 7 hours. Determine the Heat transfer rate, Surface area of the pipe and Diameter & Length of the pipe, if D = 0.012 L.Change in Temperature (in K) Heat Transfer Rate (in W) Surface Area of the Pipe (m2) Pipe Length (in m) Pipe Diameter (in mm)

Two metal rods are being heated in an oven with uniformambient temperature of 1000°C and convection heattransfer coefficient of 25 W/m2·K. Rod A is made of aluminum(r = 2702 kg/m3, cp = 903 J/kg·K, and k = 237 W/m·K)and rod B is made of stainless steel (r = 8238 kg/m3, cp =468 J/kg·K, and k = 13.4 W/m·K). Both rods have diameterof 25 mm and length of 1 m. If the initial temperature of bothrods is 15°C, determine the average temperatures of both rodsafter 5 min elapsed time.

Suppose that the 10 cm thick concrete wall of a commercial building measures 30 mby 4 m. The energy impinging on the surface is 700 W/m^2. Under these conditionsthe external air temperature is 25ºC, and the internal and external surfacetemperatures of the concrete wall are 17ºC and 40ºC, respectively. Calculate the net amount of thermal energy radiated by the wall answer = 41,880 W Data for wall: Heat transfer coefficient of air at 25ºC = 5 W/m^2KThermal conductivity of concrete = 1.2 W/mKEmissivity of concrete = 0.85Stefan’s constant = 5.7 x 10^-8 W/m^2K^4

In a cylindrical fuel rod of a nuclear reactor, heat is generated internally according to the equation: Determine the temperature drop from the centerline to the surface, considering that the rod has a diameter of 25 mm, thermal conductivity of 26 W / (mK), and has a heat removal rate from its surface of 1570 kW / (m²). Tip 1: It is not necessary to determine the value of the constant C2. Tip 2: the volumetric rate of energy generated is such that: 4.Qs"/D

IP Heat Transport in the Human Body The core temperature of the human body is 37.0 ∘C∘C, and the skin, with a surface area of 1.40 m2m2, has a temperature of 34.0 ∘C∘C.   Find the rate of heat transfer out of the body under the following assumptions: (i) The average thickness of tissue between the core and the skin is 1.20 cmcm; (ii) the thermal conductivity of the tissue is that of water.         Express your answer using two significant figures.        Without repeating the calculation of part A, what rate of heat transfer would you expect if the skin temperature were to fall to 31.0 ∘C∘C? Express your answer using two significant figures.