Questions
A piston-cylinder device initially has a volume of 1.5 m3 containing steam at 300 kPa absolute...

A piston-cylinder device initially has a volume of 1.5 m3 containing steam at 300 kPa absolute and 150 oC. It is then heated so it expands at constant pressure until it reaches a temperature of 400 oC.

Draw a diagram of the device showing system boundary and flows of energy. What boundary work is done by the cylinder, in kJ, during the expansion? State your assumptions.

1. What is the mass of steam in the piston-cylinder?

2. How much heat is added to the cylinder, in kJ, during the expansion? State your assumptions.

3. Assuming there are no irreversibilities during the expansion; S.GEN=0, does the entropy of the steam decrease, remain constant, or increase during the expansion? Explain your answer.

In: Mechanical Engineering

Find a word, number or name.The only restrictions are that it must have at least four...

  • Find a word, number or name.The only restrictions are that it must have at least four characters, and must include at least one horizontal, vertical, angled, and curved segment each  [ example: LOVE ].
  • Find parameterizations for the each characters in your word, in the xy-plane. At any time the "plotter" can only be at one location and hence the different curves making up your characters must utilize distinct time intervals!
  • If F(x,y) = (xy2) i + (x2y) j is the force field acting on the plotter tip as it traces out your characters, calculate the total work done in plotting your word
  • Draw typical velocity and acceleration vectors at various points along the curves of each character (on print-out).
  • Calculate and graph the speed (as a function of time) along each character.
  • Calculate and graph the Normal and Tangential component of the acceleration vectors (as a function of time), at least 2 locations on each character.
  • Calculate and graph the curvature (as a function of time) along each character.

In: Mechanical Engineering

Does systematic error vary during repeated readings? What is the relationship between systematic error and the...

Does systematic error vary during repeated readings? What is the relationship between systematic error and the sample size?

In: Mechanical Engineering

Find a word, number or name.The only restrictions are that it must have at least four...

  • Find a word, number or name.The only restrictions are that it must have at least four characters, and must include at least one horizontal, vertical, angled, and curved segment each  [ example: LOVE ].
  • Find parameterizations for the each characters in your word, in the xy-plane. At any time the "plotter" can only be at one location and hence the different curves making up your characters must utilize distinct time intervals!

In: Mechanical Engineering

What is the difference between SMC-R50 composite and fabric reinforced composites? I know SMC uses random...

What is the difference between SMC-R50 composite and fabric reinforced composites?

I know SMC uses random fiber orientation, is there a random fiber fabric?

Thanks

In: Mechanical Engineering

If a golf ball were dropped from a significant height and the force of Drag is...

If a golf ball were dropped from a significant height and the force of Drag is modeled by Fd=0.0057*V-0.0106, where V is the velocity in m/s the Fd is the force of drag in N. The mass of the golf ball is 0.0455 Kg.

h. How high will the golf ball bounce after the 5th impact with the concrete surface ignore drag force?

i. If drag was included for G and H what type of analysis technique would be needed

In: Mechanical Engineering

Water is discharged from a pipe outlet at a rate of 60l/s at 120.8 kPa absolute...

Water is discharged from a pipe outlet at a rate of 60l/s at 120.8 kPa absolute pressure. All pipes are 15 cm in diameter with a total length of 200 m. The total pipe length on the suction side is 10.8 m. Both reservoirs are big. The water surfaces are exposed to the atmosphere and the difference in their levels is 9 m.

Pipeline friction head loss is 0.086 m per meter length of pipe. On the suction side, fitting loss is 1.3 m while on the delivery side, fitting loss varies with the square of the velocity with K = 1.0.

a) Find the height of the water level above the pipe outlet in the receiving reservoir (m).

b) Find the total head loss of the system (m).

c) What is the hydraulic power (kW)?

d) The water to be pumped has a vapour pressure of 2335 N/m2. The cavitation parameter, s = 0.12. Find the maximum pump height possible above the surface of the water in the supply reservoir (Show clearly the calculation of all heads involved).]

(Atmospheric pressure = 101.3 kPa).

In: Mechanical Engineering

The stream function ?? in a two-dimensional flow field is given as ?? = 4?? −...

The stream function ?? in a two-dimensional flow field is given as ?? = 4?? − 3?? + 7???? (a) Prove that this flow field is irrotational and that it satisfies the continuity equation. (b) Find the potential flow function Ф(??, ??) for this flow field with boundary condition Ф = 0 at x = 2, y = 1.

In: Mechanical Engineering

Why are the tolerance characteristics categorized as forced fitting and loose can't represent shape and position...

Why are the tolerance characteristics categorized as forced
fitting and loose can't represent shape and position tolerance?

In: Mechanical Engineering

1. Control charts are usually expressed in terms of average values ​​and their dispersion. Give an...

1. Control charts are usually expressed in terms of average values ​​and their dispersion.
Give an explanation (and the reason) about the condition of a production system that is
stated in the control chart

2. From the results of the control chart analysis, how to determine the correlation between
changes in product quality conditions for the causes?

In: Mechanical Engineering

2. Surface roughness of a machining product is an important factor determine the quality of geometry....

2. Surface roughness of a machining product is an important factor
determine the quality of geometry. Explain the following:
a. Explain how the surface roughness measurement tool works!
b. Explain the concept of measuring surface roughness!
c. How are the surface measurements results stated (written down)?

In: Mechanical Engineering

Consider a case in which you have a material that support a certain stress at 75oC...

  1. Consider a case in which you have a material that support a certain stress at 75oC and you have several candidate polymers for which you need to determine the Tg using DSC or DMA(both of these are in your lab). Which technique would you select? Please provide a basis for your selection in terms of how the type of information it provides (based on how it works) and how/why it would be best suited for this application.

In: Mechanical Engineering

At the beginning of compression of an ideal Diesel cycle the gas has a temperature and...

At the beginning of compression of an ideal Diesel cycle the gas has a temperature and pressure of 400C and 90 kN/m2, respectively. The volume ratio of compression is 16:1. The maximum temperature of the cycle is 14000C. Determine, for the cycle,

  1. the pressure and temperature at each of the cycle process change points,                            [8]
  2. the work done/kg gas,                                                                                                                           [4]
  3. the thermal efficiency,                                                                                                                           [4]
  4. the work ratio,                                                                                                                                         [3]
  5. the mean effective pressure,                                                                                                                [3]
  6. the Carnot efficiency within the cycle temperature limits.                                                           [3]

Take, γ=1.4 , cp = 1.004 kJ/kg K.

In: Mechanical Engineering

One kilogram of air is taken through a constant volume cycle. At the commencement of the...

One kilogram of air is taken through a constant volume cycle. At the commencement of the adiabatic compression, the pressure and temperature are 103 kN/m2 and 1000C respectively. The adiabatic compression has a volume ratio of 6:1. The maximum pressure of the cycle is 3.45 MN/m2. Determine, for the cycle,

  1. the pressure, volume and temperature at each of the cycle process change points,                [8]
  2. the heat transferred to the air,                                                                                                            [3]
  3. the heat rejected by the air,                                                                                                                 [3]
  4. the ideal thermal efficiency,                                                                                                                 [4]
  5. cyclic work                                                                                                                                                 [4]
  6. the mean effective pressure.                                                                                                               [3]

For the air, take, R = 0.287 kJ/kg K, γ=1.4

In: Mechanical Engineering

A cooling plant adopted a two-stage cascade refrigeration system to meet the required cooling load. In...

A cooling plant adopted a two-stage cascade refrigeration system to meet the required cooling load. In both upper and lower cycles, the refrigerant leaves condenser as saturated liquid and enters compressor as saturated vapor. The isentropic efficiency of the upper cycle compressor is 80 %, while the lower cycle compressor is 70% efficient. The pressure limits of the upper and lower cycles are 1 MPa and 0.2 MPa with refrigerant-134a, respectively. Heat rejection from the lower cycle to the upper cycle takes place in an adiabatic counterflow heat exchanger where the lower cycle enters about at 0.5 MPa and the upper cycle enter about at 0.32MPa. If the mass flow rate of the refrigerant in the upper cycle is 0.28 kg/s, determine
i. the mass flow rate of the refrigerant in the lower cycle

ii. the rate of heat removal from the refrigerated space and the power input into the compressors
iii. the COP of the refrigerator,

In: Mechanical Engineering