In an industrial process, 20 mm diameter spherical steel ball bearings are heat-treated to improve their durability. For application (1), the entire ball bearing needs to be heated evenly to 1000 K. For application (2), only the outer 1 mm of the ball is to be heated to a temperature in excess of 1000 K. The properties of the ball bearing are c = 0.5 kJ/kg*K; p = 7800 kg/m³; k = 50 W/m.K. At your facility, you have access to two heating processes: a high-temperature convection oven (Tmax = 1200 K) and a liquid-salt immersion bath (Tmax = 1200 K). The convective heat transfer coefficients (h) are 50 W/m²K for the oven and 5000 W/m²K for the bath.

a) Which process would you use for each application, and why?

b) For application (1), using the process you selected in (a) calculate the time required to heat a ball that starts from 50^oC to the target temperature of 1000 K.

c) For application (2), using the process you selected in (a), calculate the time required to heat the outer layer of the ball to its target temperature.

d) For your answer in (c), what would be the temperature at the centre of the ball?

4: Consider a vapor refrigeration cycle.
a: Draw the T-s diagram of the reversed Carnot Cycle and describe what kind of problem each process of the cycle has explicitly. (We use the mixture of liquid and vapor as its working fluid.)
b: Draw a T-s diagram in the ideal refrigeration cycle and label each process explicitly. Write down the COP in terms of enthalpy.
c: There are the multipurpose refrigeration system and the multistage refrigeration system to improve the ideal refrigeration system. Describe their cycles in terms of the property diagrams explicitly and discuss the reasons why they are necessary.
d: Discuss the current status of existing refrigerants and describe how to resolve their problems explicitly.

3: Consider the Rankine power cycle using vapor and liquid.
a: Explain what kinds of problems the Carnot Vapor Cycle has.
b: Draw a T-s diagram for the ideal Rankine cycle and label each process explicitly.
c: There is a method to lower the condenser pressure in order to improve the efficiency of the ideal Rankine cycle. Explain its advantages and disadvantages explicitly.
d: Name the gas power cycle which uses the same four processes in its cycle and draw the T-s diagram and the P-v diagram for the gas power cycle.

How to calibrate portable CMM(Coordinate Measuring Machine)?

thermodynamics

show whey with equations Cv can be calculated using enthalpy while Cp using the internal energy

A 5-cylinder square engine with a total stroke volume of 3.5 liters, operating according to a 4-stroke cycle, operates at 2500 rpm. Since the mechanical efficiency of the engine is 62% and the Indicative work produced for each cylinder is 1 kJ, find the specific power of the engine in kW / cm2.

In the flow around a cylinder, boundary layer separation occurs due to (SELECT CORRECT ANSWER)

A boundary layer is

Two flows may be classified as having dynamic similarity if

8: There is a boundary between a system A with a low temperature TL = 25 C and another system B with a high temperature TH = 89 C. The surrounding of the two systems has an equilibrium temperature 15 C.
a: Schematically sketch the transfer diagrams of temperature, heat, entropy, and exergy across the boundary between A and B.
b: Calculate the entropy at B and the entropy generation if the entropy at A is 2.9 kJ/K.
c: Calculate the exergy at B and the exergy destruction during the process.

Air at 1 atm and 80 ºC is used for the fluidization of catalyst pellets in 2.5 mm diameter in a vertical cylindrical reactor. The density of the catalyst particles is 3000 kg/m³. The catalyst particles have a sphericity (Øs) of 0.8 and . What should be the minimum limit of the air velocity? Explain the reasons

b) If the air flow rate is 45000 kg/h and the operational air velocity is 1.5 Vt, what should be the reactor diameter? Viscosity of air is 2.1x10^-5 kg/m.s

A roller coaster starts from rest at A, rolls down the track to B, describes a circular loop of 12-m diameter, and travels up and down past point E. Assume that there is no energy loss due to friction. Given: h = 20 m. Shoe the free body diagrams at points B,D, and E. Determine the force exerted by his seat by a 80 kg rider at B and D and the minimum value of the radius of curvature at E if the roller coaster is not to leave the track at that point.

Write a report on the security threats faced by india

can you answer those question as a field service engineer for job interview

1-Please describe in detail your knowledge of electrical engineering?

2-Please describe in detail your knowledge of mechanical engineering?

3-Please describe in detail your knowledge of computer software?

4-What does customer service mean to you?

5-What interests you most about this position?

6-What are your career goals?

7-Why are you looking for another job?

8-What is your business travel tolerance?

9-What has been your business travel levels in your past opportunities?

Consider the vertical rear window of an automobile that has a thickness L= 9 mm and height H=0.5 m with heating wires that create uniform volumetric heating. The window interior is exposed to ambient air at 10°C and the window exterior to air at -10°C which moves in parallel flow over the surface with a velocity of 20 m/s. The surface temperature of the window exterior is 12°C. Find the volumetric heating rate necessary to keep the window interior at 16°C. What is the convective heat flux for the interior and exterior of the window?