A 2 cm thick steel slab heated to 5250 C is held in air stream having a mean temperature of 25° C. determine the time interval when the slab temperature would not depart from the mean value of 250 C by more than 0.5º C at any point in the slab when Boit Number = Bi = 0.0078, Fourier number = Fo = 0.127 I %3D

One of the strengths of numerical methods is their ability to handle complex boundary conditions. In the sketch, the boundary condition changes from specified heat flux ′′ qs (into the domain) to convection, at the location of the node (m, n). Write the steady-state, two- dimensional finite difference equation at this node.

2. Calculate the mass of silver initially at 445 °C which would be needed to be dropped into a 435 mL sample of water initially at 23.0 °C in an insulated container to raise the temperature of the water to 33.5 °C. The specific heat capacity of water is 4.184 J K-¹ g¹ and the molar heat capacity of silver is 25.9 J K¹ mol¹¹. 2 Tot 21

A food product wants to be produced in a small round shape (pellet) by freezing it in a water blast freezer freezer. Air freezer operates at -25 ° C. The initial product temperature is 25 ° C. The pellet has a diameter of 0.5 cm, and a density of 980 kg / m3. The initial freezing temperature is -2.5 ° C. The latent heat of freezing of the product is 280 kJ / kg. The thermal conductivity of the frozen product is 1.9 W / (m ° C). The convective heat transfer coefficient is 50 W / (m? K). Calculate the freeze time.