A multi-stage gas turbine is to be designed with impulse stages, and is to operate with an inlet pressure and temperature of 6 bar and 900 K, and an outlet pressure of 1 bar. The isentropic efficiency of the turbine is likely to be 85 per cent. All the stages are to have a nozzle outlet angle of 15 degrees, equal inlet and outlet blade angles, a mean blade speed of 250 m/s and equal 5 kJ/kg K o inlet and outlet gas velocities. Estimate the number of stages required. Assume cp 1.15 kJkg K and y 1.333.

[Suggested Answer: 2.54 stages (practically 3 stages)

Engine oil at a hundred degrees Fahrenheit passes through 1/8 inch diameter tube at a volume flow rate of 50ft³/m . If the surface temperature is 150 degrees F, what is the heat transfer rate Q.  

Q = ?????? Btu/h. Assume a smooth surface and the tube length is 5 meters.

From the book use p (density) = 54.24 lbm/ft^3,_,

Specific heat = 0.4809 Btu/(lbm*R)    R=Rankin,

Thermal conductivity = k= 0.08207 Btu/(h*ft*R)   

u = 7.617 * 10 ^-2 lbm/ft*s, u = fluid viscosity

Pr = 1607, Pr = Prandtl number

Design a DISC BRAKE based on the given below. Draw schematic diagram and show complete solutions/computations with direct subtitution. Also compute for the forces involved in the system.

GIVEN:

Braking Force (HP) = 15 HP

N (RPM) = 1800 RPM

Brine (S.G. = 1.2) flows through a 200 gpm pump. The pump outlet is 6” pipe and is 4 feet above the 8” pipe inlet. The inlet vacuum is 6” Hg. Outlet pressure is 20 psig. What is the water horsepower (WHP) of the pump? What color should the pipes be painted that are connected to this pump?

A piston-cylinder heat engine has five kilograms of air as the working fluid. Analyze this engine as a Carnot engine and determine the work of expansion and the amount of heat rejected in KJ assuming constant specific heat at 300k. During the heat rejection, the temperature is 300?. There is a temperature difference of 600 degrees in the engine. At the beginning of the heat rejection process, the pressure is .2MPa and during heat addition the volume doubles. Draw the P-v diagram and T-s diagram for the cycle.

Design documents state that a total of six M10 x 1.5, class 5.8 bolt and nut pairs fasten a 15 mm thick steel cap to a 15 mm thick steel flange. Safety requirements dictate that this fastening system must possess a safety factor of 1.5. Use the preload determined in Part A when calculating the bolted joints safety in dynamic loading in Part B. (Note: One may find km using the method outlined in class, or one may use Eqn. 15.19 on p. 929). a) If the steel cap experiences a static external load of 30 kN, is this design safe? b) If the steel cap experiences an external load that varies from 10-20 kN and the bolted joint must be 99% reliable, is this design safe?

Q2/ In one of applications, wanted to condition laboratory at inside design condition DBT-24 °C and 50% Rh and outside design condition DBT-44 °C and WBT-27 °C. Total sensible load for the space is 35 kW and total latent load for the space is 19 kW. Rate of supplied air to the space is 11050 m'/hr and rate of outside ventilation air is 4250 m/hr. The recireulated air is mixing with the outside air and then entering to cooling coil and leaving at 95% Rh then the air is passing through heating coil before supply to the space. Determine: 1.Condition of supply air to the conditioned space (DBT & RH): 2.Condition of air before and after cooling coil (DBT & RH); 3. Sensible load of heating coil; 4.Sensible load and latent load and total load of cooling coil: 5. Apparatus dew point (ADP) for the cooling coil; 6. Draw the cycle on the psychrometric chart.

To be able to use the conservation of energy on a moving body to determine key characteristics about the mechanics of the system. A package of mass m = 0.70 kg is pushed across the surface by a jet of compressed air during an assembly-line process. The package is moved through a distance of s = 49.0 cm . The package and the surface are known to have a coefficient of kinetic friction of ? k = 0.13 . The package is initially at rest for this process.

A)If the package must be moving at a speed of v = 10.5 cm/s when it has reached the distance of 49.0 cm , determine the average force that the jet of compressed air must supply to the package

B) If it is now desired that the package be at rest when it has reached the distance of 49.0 cm , determine the average force that the jet of compressed air must supply to the package if the package is initially traveling in the s direction at a velocity of v = 19.0 cm/s .

C) If the plant has changed the mass of the package on the assembly line to m = 1.25 kg , determine the average force that the jet of compressed air must supply to the package if the package and surface now have a coefficient of kinetic friction of ?k = 0.18 . Use the same initial and final conditions as in Part B.

A major application of ferro- and ferrimagnetic materials is in transformer and motor cores. Materials are required that are magnetically soft (high permeabilities – they are magnetized easily at low applied fields and a low coercive field) with large power-handling capacity and low losses. Why cannot pure iron metal be used in transformer cores?

Account for the magnetic behavior of the following spinels:
(a) ZnFe2O4 is antiferromagnetic
(b) MgFe2O4 is ferrimagnetic and its magnetic moment increases with temperature

c) MnFe2O4 is ferrimagnetic and its magnetic moment is independent of temperature

equation of motion

Material Science:

If you were to be given a DSC (Differential scanning calorimetry) trace of a polymer, how would you identify changes and characteristics of the polymer? I understand this is a vague question, but please try your best, I'm lost!

Thermodynamic

In a piston-cylinder air at 100 kPa and 15°C undergoes the following cycle. First, it is compressed isentropically to a compression ratio of 20. Then 1800
kJ/kg of heat is transferred to the air at constant pressure. Afterwards the air expands isentropically. In the last step, heat is removed at constant volume until the air reaches its original state. Assuming air behaves as an ideal gas and with Cp and Cv independent of temperature, determine the:
(a) pressure and temperature at each point in the cycle,
(b) thermal efficiency of the cycle, and
(c) mean effective pressure.

Please work by step and orderly to easy work

Define hardness, and explain the variation of hardness with respect to the slip systems in the material.

A Carnot heat engine within a piston cylinder has 10 kg of air as the working fluid and operates between 1000 K and 350 K. During the heat addition process the pressure changes by a factor of 2.5. The volume at the end of the isentropic compression process is 5m^3. Determine the pressure at each state in kPa and the net heat of the cue in KJ assuming Constant Heats at 300 K. Draw a P-v and T-s diagram