Q/ A vapor-compression refrigeration cycle working with R22
contains a liquid-to-suction
heat exchanger. The saturated liquid refrigerant at 40 °C leaving
the condenser and entering
the heat exchanger is used to superheat the saturated vapor
refrigerant leaving the evaporator
at 7 °C by 8 °C. If the compressor is capable of pumping 5 l/s of
vapor refrigerant measured
at the inlet to the compressor and the compression processes are
considered isentropic in
both cases listed below, determine;
(a) The refrigerating capacity in kW, the compressor power in kW,
and the COP of the
system in the absence of the heat exchanger.
(b) The refrigerating capacity in tons refrigeration, the
compressor horsepower, and the
COP of the system in the presence of the heat exchanger.?
In: Mechanical Engineering
2 kW of power will be trasnmitted via chain-sprocket system. Rotational speed of input shaft is 20 rpm. Required approximate rotational speed of input shaft is 20 rpm. Required approximate rotational speed for the out shaft is 7 rpm. Approximate distance between center lines of input and output shafts should be 900 mm. This chain-sprocket system is used for an elevator and it is asked to use single or multiple DIN 8187 chain with 31.75 mm pitch.
a) Calculate number of teeth on sprocket, which is on output shaft, is number of teeth on the sprocket on input shaft is 19.
b) Calculate input power for selection of chain and select the appropriate chain type.
c) Calculate pitch circle diameters of driving and driven sprockets, linear velocity of chain, length of chain, (number of chain links), and exact center line distance between driving and driven sprocket.
d) Calculate factor of safety of the selected chain.
In: Mechanical Engineering
In: Mechanical Engineering
Study and indicate a method of marking of 8 holes on a single Pitch Circle Dia (PCD) of a round disc (illustration). The part of the problem is that of many of these discs are to be produced in a day (Bulk Production), what is the solution for quick marking and the quickest way of drilling holes so that the process time is minimized. No special machine is to be utilized. Standard machine shop equipment (Like manual Lathe/ Milling/ Drill machines) is to be taken into consideration for a solution.
Give a comprehensive answer with example not exceeding a single page.
In: Mechanical Engineering
1. Evaluate a music wire spring with plain ends where the wire
diameter is 0.100” and the outer
diameter is 0.600”. The desired spring rate is 100 lbf/in and the
free length is 2.4”. Let the load
safety factor be 1.00.
a) What is the spring index, C?
b) What is the total number of coils, Nt?
c) What is solid length, Ls?
d) What is the maximum suggested load?
e) What is the maximum suggested deflection?
f) What is the force to close to solid, Fs?
g) What is the critical length?
h) What is the critical frequency?
i) What is the factor of safety, solid, ns?
In: Mechanical Engineering
Find the solution for each part
A) In the tensile and wood experiments, you learned about the stress-strain behaviors of different materials. Sketch a thoroughly labeled stress-strain diagram to explain the mechanical properties of 1) window glass, 2) copper metal, 3) annealed copper metal. Make sure to have all three curves on the same plot. Please label the x and y-axis, and the different mechanical parameters (Ultimate Tensile Strength, Yield Stress, Rupture Stress and Modulus of Elasticity).
B) Hookes law is only applicable in the plastic region of the stress-strain curve. (True/False)
C) Polymers are more ductile than ceramics. (True/False)
In: Mechanical Engineering
Name the three Functions that advanced manufacturing automation, explain them in a few wards, and give an example on each one of them?
In: Mechanical Engineering
Question 7
An axial flow water Kaplan turbine operates under a head of 2.5 m while the rotational speed is 75 rpm. The runner tip diameter is 4.8 m and the hub diameter is 2.4 m. The flow rate is 48.5 m3/s and hydraulic efficiency of 93%. Assuming zero whirl at exit, determine: Sketch the inlet and outlet velocity triangles at the MEAN radius and calculate:
1.1 The runner blade inlet and exit angles at mean radius. ANS: +/- 74˚
1.2. The theoretical power developed? ANS: +/- 1.1MW
1.3. The mechanical efficiency if the shaft output power is 980 kW? ANS: +/- 88.6%
This is only one question, sir. Pls solve it in a comprehensive manner showing all the steps in detail. Thank you!!
In: Mechanical Engineering
I have Rockwell and Brinell hardness test data. How determine what kind of material I have from the hardness test?
In: Mechanical Engineering
Liquid phenol at 298 k, 100kPa is burned with 152% theoretical air at 295k, 100kPa. Determine the adiabatic flame temperature. Enthalpy of liquid phenol is given as -96,232 kJ/kmol
In: Mechanical Engineering
a four bar mechanism has the following dimensions. DA=300mm, CB=AB=360mm DC=600mm. the link DC is fixed and the angle ADC is 60⁰. The driving link DA rotates uniformly at a speed of 100rpm clockwise and the constant driving torque has a magnitude of 50 N-m. Determine the velocity of the point b and angular velocity of the driven link cb
In: Mechanical Engineering
In: Mechanical Engineering
Ammonia is initially at a temperature of -10° C and a specific volume of 0.07 m3/kg. The ammonia undergoes an isobaric expansion to a final specific volume of 0.22 m3/kg. Evaluate the specific work done on the ammonia in kJ/kg and the specific heat transfer to the ammonia in kJ/kg. Neglect changes in kinetic energy and potential energy.
Carbon dioxide is contained in a piston-cylinder assembly with an initial pressure and temperature of 8 lbf/in2 and 100° F, respectively. The carbon dioxide has a mass of 0.05 lb. The carbon dioxide is expanded isothermally to a final volume of 1 ft3. Model the carbon dioxide as an ideal gas with constant specific heats. Evaluate the specific heats at 100° F. Determine the amount of work done on the gas in Btu and the heat transfer to the gas in Btu. Neglect changes in kinetic energy and potential energy.
An ideal gas with constant specific heats undergoes a process from an initial pressure and specific volume of 80 kPa and 40 m3/kg to a final specific volume of 20 m3/kg. During the process, the hydrogen’s pressure and specific volume are related through the equation given below. In the equation, ?? and ?? are the initial pressure and specific volume of the hydrogen, respectively. Determine the specific work done on the gas in MJ/kg and the specific heat transfer to the gas in MJ/kg. The ideal gas has a molar mass of 2.0 kg/kmol and a specific heat at constant volume of 7.5 kJ/(kg∙K). Neglect changes in kinetic energy and potential energy.
? = ?? ⋅ [2 − (?/??)]
In: Mechanical Engineering
Consider a two-stage cascade refrigeration system operating between the pressure limits of 1.2 MPa and 200 kPa with refrigerant R717 (Ammonia) a as the working fluid. The refrigerant leaves the condenser as a saturated liquid and is throttled to a flash chamber operating at 0.45 MPa. Part of the refrigerant evaporates during this flashing process, and this vapor is mixed with the refrigerant leaving the low-pressure compressor. The mixture is then compressed to the condenser pressure by the high-pressure compressor. The liquid in the flash chamber is throttled to the evaporator pressure and cools the refrigerated space as it vaporizes in the evaporator. The mass flow rate of the refrigerant through the low-pressure compressor is 0.15 kg/s. Assuming the refrigerant leaves the evaporator as a saturated vapor and the isentropic efficiency is 80 percent for both compressors, determine (a) the enthalpy at the exit of the high pressure compressor, (b) the entropy at exit of low pressure compressor , (c) the mass flow rate of the refrigerant through the high-pressure compressor, (d) the rate of heat removal from the refrigerated space, and (e) the COP of this refrigerator. Also, determine (f) the rate of heat removal and (g) the COP if this refrigerator operated on a single-stage cycle between the same pressure limits with the same compressor efficiency and the same flow rate as in part (c)
In: Mechanical Engineering
6. (a) Name a conductor, an insulator, a semiconductor, a ductile material and a brittle material.
(b) Why does a typical conductor show a relatively high electrical conductivity and a high ductility at room temperature? Comment on its electrical conductivity when it is heated.
(c) Derive the units of ductility and electrical conductivity.
In: Mechanical Engineering