Fluid (air) enters a nozzle at 150 m/s, 26.85 oC, and at a pressure of 200 kPa. Assuming isentropic flow, evaluate the temperature and pressure of the fluid at a location where the speed of fluid equals the speed of sound. What is the ratio of the area at this location to the entrance area?
In: Mechanical Engineering
The spray characteristics of a highly toxic liquid fuel, especially particle their diameter is required. In the examination, the particle diameter dp, spray outlet rate U, liquid viscosity µ, surface tension Y, density ρ and spray it is suggested that the spray injector is connected to the outlet diameter D and is safe it is suggested that an experiment can be carried out with water, design and state the requirements for the creation of this experiment and obtain how to use your data for prototype fuel in mathematical terms If necessary, write with dimensionless numbers.
In: Mechanical Engineering
In: Mechanical Engineering
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 50oC 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?
In: Mechanical Engineering
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.
In: Mechanical Engineering
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.
In: Mechanical Engineering
How to calibrate portable CMM(Coordinate Measuring Machine)?
In: Mechanical Engineering
thermodynamics
show whey with equations Cv can be calculated using enthalpy while Cp using the internal energy
In: Mechanical Engineering
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: Mechanical Engineering
In: Mechanical Engineering
In the flow around a cylinder, boundary layer separation occurs due to (SELECT CORRECT ANSWER)
energy losses in the boundary layer that prevent it from remaining attached. |
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the Mach number being too high |
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the surface being rough |
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a low buoyancy force. |
A boundary layer is
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Two flows may be classified as having dynamic similarity if
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In: Mechanical Engineering
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.
In: Mechanical Engineering
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
In: Mechanical Engineering
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.
In: Mechanical Engineering
Write a report on the security threats faced by india
In: Mechanical Engineering