A food product with 73% moisture content in a 10 cm diameter can wants to be frozen. The density of the product is 970 kg / m³, the thermal conductivity is 1.2 W / (m K), and the initial freezing temperature is -2.5 ° C. After 14 hours in the freezing medium -40 ° C, the product temperature becomes -10 ° C. Estimate the convection heat transfer coefficient of the freezing medium. Assume the can as an infinite cylinder. h = Answer W / (m² K).

Two identical 7.5-cm cubes of copper at 425 and 90°C are brought into contact. Assuming that the blocks exchange heat only with each other and that there is no resistance to heat flow as a result of the contact of the blocks, plot the temperature of each block as a function of time, using the lumped-capacity method of analysis. That is, assume the resistance to heat transfer is the conduction resistance of the two blocks. Assume that all surfaces are insulated except those in contact.

Number 3 A food product with 73% moisture content in a 5 cm diameter can wants to be frozen. The density of the product is 970 kg / m³, the thermal conductivity is 1.2 W / (m K), and the initial freezing temperature is -1.75 ° C. After 10 hours in the freezing medium -25 ° C, the product temperature becomes -10 ° C. Estimate the convection heat transfer coefficient of the freezing medium. Assume the can as an infinite cylinder. identify: a. h = Answer in W / (m² K).

2. The wall of a furnace is made up of a material which has thermal conductivity of 1.65 W/m•C and a thicknesses 250 mm. The inner side of the furnace wall is exposed to hot gases at 1000 °C with a convection coefficient of 25 W/m2°C and the inside the surface is at 800 °C. The air outside the furnace is at 25°C with a convection coefficient of 12 W/m2°C. a. Draw a clear diagram representing the system b. Determine the temperature of the outside surface of the furnace C. The rate of heat loss from the furnace.

Problem 3 A novel material is suddenly exposed on one side to a fluid material. The material has an overall thermal gradient of °C W -7,000 with a thermal conductivity of 23.8. The fluid m m.K • has a temperature of 30° C and a heat transfer coefficient of 325 W m². K. material. . Calculate the temperature at the surface of the

Steel pipe (outer diameter 100 mm) is covered with two layers of insulation. The inner layer, 40 mm thick, has a thermal conductivity of 0.07 W / (m K). The outer layer, 20 mm thick, has a thermal conductivity of 0.15 W / (m K). Pipes are used to deliver steam with a pressure of 700 kPa. The temperature on the outer insulation surface is 24 ° C. If the pipe is 10 m long, determine the following: (assuming that the conduction heat transfer resistance of the steel pipe and the vapor convection resistance are negligible). a. Heat loss per hour. = AnswerkJ / hour. b. Temperature between insulation layers. = Answer° C.

A copper electric wire of radius R, = 1 mm is isolated by a layer of PVC so that the outer radius of the wire Rg = 2 mm, as shown in Figure below. The wire exchanges heat with the air at 20°C according to a heat transfer coefficient h=20 W/m2°c: Given that : k=copper electrical conductivity=4.0 × 1070hm-'m¯! kpvc= PVC thermal conductivity = 0.3- m°C kco = copper thermal conductivity = 100 m°C %3D (amp/m)² And that the electrical heating source is given by : S, amp²s /kgm³ If the temperature (T,) on the outer surface (r = RG) is 25°C, what is the electrical current C (amp) that passes through this wire? Dont forget to state your hypothesis clearly.     Hi, Could you please tell me what the book's name is? Thank you!

D -A₂ = Ac Obtain a relation for the fin efficiency for a fin of constant cross-sectional area Ac, perimeter p, length L, and thermal conductivity k exposed to convection to a medium at T with a heat transfer coefficient h. Assume the fins are sufficiently long so that the temperature of the fin at the tip is nearly T... Take the temperature of the fin at the base to be Tb and neglect heat transfer from the fin tips. Simplify the relation for (a) a circular fin of diameter D and (b) rectangular fins of thickness t. h, T

A large slab of aluminum has a thickness of 10 cm and is initially uniform in temperatureat 400◦C. It is then suddenly exposed to a convection environment at 90◦Cwith h=1400 W/m2 · ◦C. How long does it take the center to cool to 180◦C?

Please answer A