In: Mechanical Engineering
In: Mechanical Engineering
Lets say that we are testing an engine that produces 17 kW of power. As this engine is operating, it absorbs 95 kW of heat from the surrounding air at 17 C. The air is then exited from a combustor into a room at 20 C.
What is the reversible power?
Group of answer choices
-32.9 kW
32.9 kW
5.882 kW
-5.882 kW
In: Mechanical Engineering
Refrigerant 134a, initially (state 1) a saturated liquid at -80C, is contained in a piston-cylinder assembly. The water undergoes a process to the corresponding saturated vapor (state 2), during which the piston moves freely in the cylinder. The change of state is brought about by heating the water as it undergoes an internally reversible process at constant pressure and temperature. If the mass of the refrigerant is 0.1 kg, determine (a) heat transfer using first law of thermodynamics in kJ and (b) heat transfer using second law of thermodynamics in kJ.
In: Mechanical Engineering
Air passes through a jet engine nozzle operating at steady state. The flow at the nozzle inlet has a temperature of 900° F. The nozzle inlet has an area of 5 ft2. The flow at the nozzle outlet has a temperature of 875° F, a specific volume of 90 ft3/lb, and a velocity of 600 ft/s. The nozzle outlet has an area of 2 ft2. Model the air as an ideal gas with constant specific heats. Evaluate the specific heats at 900° F. Assume the nozzle is well insulated and neglect potential energy changes. Determine the velocity in ft/s and specific volume in ft3/lb of the flow at the inlet.
In: Mechanical Engineering
What are the Ethical and professional responsibilities of the pusher type system in the industry?
In: Mechanical Engineering
A gas turbine expands air adiabatically at 1000 kPa
and 550 ⁰C to 120 kPa and 130⁰C. Air enters the
turbine through a 0.25 m
2 opening with an aveage velocity of 45 m/s, and exhausts through a
1 m2
opening. Assume the air is ideal gas with constant specific heats.
Take the constant pressure specific
heat and gas constant of air as Cp= 1.05 kJ/(kg K) and R=0.287
kJ/(kg K), respectively. Determine;
(a) the mass flow rate of air through turbine and
(b) the power produced by the turbine.
In: Mechanical Engineering
1. Discuss Professional Responsibility of engineers in a situation of ethical dilemma. CLO1(2.5)
2. How individualism effect the situation when whistle blowing is going on? CLO2 (2.5)
3. Why safety is important in state of practicing whistle blowing? CLO3 (2.5)
4. How much the impact of personality and cultural norms effect on engineer's responsibilities in society? CL04 (2.5)
CLO 1: Discuss awareness of professional, social and ethical responsibility in engineering practice
CLO 2: Distinguish between individual behavior and behavior in a group
CLO 3: Choose different safety issues in engineering practice
CLO 4: Explain the impact of personality and cultural norms on engineer's responsibilities in society
In: Mechanical Engineering
Define the following items?
1-Sensor; 2- Signal conditioner; 3- Zero error; 4- Accuracy; 5- Hysteresis;
In: Mechanical Engineering
Making intricate and very small metal parts by casting is a difficult task. Suggest the casting technique for that and explain the steps in that technique.
In: Mechanical Engineering
CO2: Explain the ethical duties and responsibilities of engineers in society related to legal, management and entrepreneurship aspects
PO9: Apply ethical principles and commit to professional ethics and responsibilities and norms of engineering practice
In: Mechanical Engineering
Apply ethical principles and commit to professional ethics and responsibilities and norms of engineering practice
In: Mechanical Engineering
List the high-level benefits of programming languages and identify the particular language(s) which are most closely associated with each such specific benefit.
In: Mechanical Engineering
HW Problem 5: A 150 kW motor drives a hollow round shaft at 1,200 rpm. The outer diameter of the shaft is 100-mm and the inner diameter is 0.95*outer diameter. It is made of AISI 1050 WQ&T at 425- deg C.
(a) Look online or the book and explain briefly what “WQ&T” in the material designation stand for, and how it is different than OQ&T. Which is stronger at the specified temperature?
(b) Determine the maximum torsional shear stress (Tau max) in the hollow shaft. Write the units. Hint: Use the kW power equation, find torque, and find J to find Tau max. Use N, mm, MPa.
(c) Determine the safety or no safety factor for static loading (ns) according to (i) Tresca theory, and (ii) von-Mises theory. Hint: Read Sy from table and then calculate Ssy by Tresca and von-Mises. Then use (ns,Tresca) = (Ssy,Tresca) / (Tau max); (ns,von) = (Ssy,von) / (Taumax).
(d) If the calculated safety factor is more than 4.0, what parameters would you change to bring it down below 4.0 (and of course, above 1.0)?
In: Mechanical Engineering
A vertical close coiled helical spring must have a stiffness of
4,3 kN/m. The maximum shear stress of 130 MPa is induced by a load
of 720 N. With the spring fully compressed, the vertical height
over the coils is 250 mm. If G = 79 GPa, calculate:
3.1 the required wire diameter for the spring;
3.2 the mean coil diameter and the number of coils.
In: Mechanical Engineering