Chapter 15, Problem 15.4E

heat and mass transfer

heat and mass transfer

heat and mass transfer

Steam at atmospheric pressure (Tsat = 100oC, hfg = 2.257×106 J/kg) is in contact with a horizontal tube through which a cooling fluid is circulated. The tube has 0.0334 m outside diameter, 1 m length, and an outside-surface temperature that is maintained at 60oC. Determine the rate of heat that the cooling fluid must remove and the condensation rate. For water at average temperature, ρ L = 974 kg/m3, k = 0.668 W/m·K, ρ v = 0.516 kg/m3, ν L = 0.364×10-6m2/s. g =9.81 m/s2.

Surface A1 of the system shown in the figure below is a graybody with emissivity of 0.56 andsurface A2 is a blackbody.Can you determine view factors F1-2 and F2-1. And draw an analogous electrical circuit based on Ohm’s law and determine the net radiation heat transfer from surface A1 to surface A2 if T1 = 500oC and T2 = 27oC. For the graybody, α = ε. Stefan-Boltzmann constant, σ = 5.676 × 10-8 W/m2·K4.

An aluminum saucepan has a handle that is fixed to its wall. The handle itself is made of low carbon steel, and will have a plastic grip attached to it that is comfortable to grasp. Before selecting a plastic, it is necessary to have information on the temperature of the carbon steel handle. The carbon steel handle can be considered as a rod 11 mm in diameter and 45 mm long. When being used over a stove burner, the ambient temperature T∞ is 30 oC, and the temperature at the base of the handle reaches T0 = 100 oC. The convective heat transfer coefficient h is 8 W/m2·K and k = 43 W/m·K for low carbon steel. Can you derive the differential equation for the temperature of handle with x as a spatial variable and determine the temperature of handle at the position of 40 mm from the base. Using the general solution attached.   Also Can you determine the total heat transfer rate (q) from the handle using the above temperature profile equation and determine the total heat transfer rate (q) from…

For forced convection, the important variables, their symbols, and dimensional representations are listed below. From the Buckingham method of grouping the variables, the rank of the dimensional matrix is 4. What is the number of independent dimensionless groups in this case? By utilizing the dimensional- analysis approach, find a dimensionless group. (Show just one dimensionless group you can find)

A parallel flow heat exchanger with surface area of 62.5 m2 is to be designed for cooling oil at 80oC with specific heat of 2.5 kJ/kg·oC and mass flow rate of 5.0 kg/s. Water at 15oC flowing at 9.94 kg/s is used as the cooling fluid (cp = 4.19 kJ/kg·oC). 1 W = 1 J/s Can you determine the heat transfer rate and outlet temperatures, assuming an overall heat transfer coefficient equal to 300 W/m2·oC. For heat transfer rate, use the effectiveness, ε, and Check the results with log-mean temperature difference approach. (Calculate the heat transfer rate and compare the value in (1))v

A 5 cm diameter, 60 cm long aluminum cylinder initially at 50 oC is submerged in an ice-water bath at 2 oC. The convective heat transfer coefficient between the metal and the bath is 550 W/m2·K. Using the lumped parameter analysis, derive the equation below. Show procedures in detail please.And determine the central temperature of the aluminum after 1 min. For aluminum, k = 236 W/m·K, ρ =2702 kg/m3, and cp= 896 J/kg·K. (1 W = 1 J/s) Then calculate the cumulative heat transfer for the first 1 min.(the first law of theromodynamics is attached and the. needed equation to derive)