Engineering, 11.10.2021 06:00 yanelyportillo7
A sphere 30mm in diameter initially at 800K is quenched in large bath having a constant temperature of 320K with a convection heat transfer coefficient of 75W/m^2. K. The thermo-physical properties of the sphere material are rho = 400kg/m^3, c = 1600 J/kg. K, and k = 1.7W/m K. a) Sketch the temperature gradient in the sphere over time with temperature (y-axis) and radius (x-axis) showing several lines to represent the initial time, an intermediate time, and the temperature at after a long time has elapsed. Note the boundary conditions you assumed in the center of the sphere and the edge of the sphere and show them on your sketch b) Calculate the Biot number and determine the best solution path using a characteristic length of gamma _o. c) Calculate the time required for the surface of the sphere to reach 415K [seconds]. d) At the time found, determine the heat flux [W/m^2] from the surface of the sphere.
Answers: 1
Another question on Engineering
Engineering, 04.07.2019 18:10
What difference(s) did you notice using a pneumatic circuit over hydraulic circuit.explain why the pneumatic piston stumbles when it hits an obstacle.
Answers: 2
Engineering, 04.07.2019 18:10
The mass flow rate of the fluid remains constant in all steady flow process. a)- true b)- false
Answers: 1
Engineering, 04.07.2019 18:10
Steel is coated with a thin layer of ceramic to protect against corrosion. what do you expect to happen to the coating when the temperature of the steel is increased significantly? explain.
Answers: 1
Engineering, 04.07.2019 19:20
Acommercial grade cubical freezer, 4 m on a side, has a composite wall consisting of an exterior sheet of 5.0-mm thick plain carbon steel (kst= 60.5 w/m k), an intermediate layer of 100-mm thick polyurethane insulation (kins 0.02 w/m k), and an inner sheet of 5.0- mm thick aluminium alloy (kal polyurethane insulation and both metallic sheets are each characterized by a thermal contact resistance of r 2.5 x 104 m2 k/w. (a) what is the steady-state cooling load that must be maintained by the refrigerator under conditions for which the outer and inner surface temperatures are 25°c and -5°c, respectively? (b) for power saving purpose, which wall material should be increased/reduced in. thickness in order to reduce 50% of the cooling load found in part (a)? redesign the thickness of the proposed material. 177 w/m-k). adhesive interfaces between the q=575.93 w
Answers: 2
You know the right answer?
A sphere 30mm in diameter initially at 800K is quenched in large bath having a constant temperature...
Questions
