In a dairy operation, milk at a flow rate of 250 L/h and a cow-body temperature of 38.6 oC must be chilled to a safe-to-store temperature of 13 oC or less. Ground water at 10 oC is available at a flow rate of 0.72 m3/h. The density and specific heat of milk are 1030 kg/m3 and 3860 J/kg∙K, respectively. By using NTU method, determine the UA product of a counterflow heat exchanger required for the chilling process. Determine the length of the exchanger if the inner pipe has a50-mm diameter and the overall heat transfer coefficient is U = 1000 W/m2∙K.

The rate of heat transfer from a body to the surroundings is governed by the following equation: D= hA(Tsur - Tbody) Where dis the heat transfer rate (J/s) h is the heat transfer coefficient A is the heat transfer area (m²) Tsur is the temperature of the surroundings (K) Tpody, is the temperature of the body (K) Find the units for the heat transfer coefficient, h.

The liquid food is flowed through an uninsulated pipe at 90 ° C. The product flow rate is 0.25 kg / s and has a density of 1000 kg / m³, a specific heat of 4 kJ / (kg K), a viscosity of 8 x 10-6 Pa s, and a thermal conductivity of 0.55 W / (m) K). Assume that the change in viscosity is negligible. The internal diameter of the pipe is 25 mm with a thickness of 3 mm made of stainless steel (k = 15 W / [m ° C]). The outside temperature is 15 ° C. If the outer convective heat transfer coefficient is 18 W / (m² K), calculate the heat loss at steady state per meter pipe length.    a. Find the convection coefficient in the pipe = AnswerW / m² ° C.    b. Calculate heat loss per meter pipe length = Answerwatt.

An air pipe carries cool air at an inlet bulk temperature of 15C and a velocity of 12 m/s. The pipe is made of carbon steel of 0.25 m diameter, it is not insulated, and it( the pipe) will be maintained at temperature of 120C in order to raise the flowing air temperature to 45C. Calculate the Reynolds number, the heat transfer coefficient in W/(m^2K) and the lenght of this pipe in meters. Use Table A.4 to read the air properties.

Heat Transfer Question