EBK 3I-EBK: WELDING PRINCIPLES & APPLIC
8th Edition
ISBN: 9780176919764
Author: Jeffus
Publisher: VST
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Chapter 2, Problem 35R
Why is it important to keep a welding area clean?
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1. Steam leaves the boiler of a power plant at 5 MPa, 500°C as shown in the following figure. As
the steam passes to the turbine, the temperature drops to 496°C before it enters the turbine due to
a heat loss through the pipe's insulation. The pressure drop in the pipe connecting the boiler to
the turbine is negligible. The steam then passes through an adiabatic turbine and exits at 10 kPa.
The turbine has an isentropic efficiency of 85% and is delivering 1000 MW of power. Determine
the following.
P = 5 MPa
T₁ = 500°C
Boiler
P₁₂ =5 MPa
Τ =496°C
7 = 85%
W = 1,000 MW
P=1 atm
To=25°C
Turbine
3+ P = 10 kPa
a. The heat transfer rate from the pipe connecting the boiler to the turbine (in MW)
b. The change in flow exergy rate as the steam flows through the pipe (MW). This represents
exergy that is lost to the environment and unavailable for power delivery. Comment on the
magnitude of this exergy loss compared to the power delivered by the turbine. What factor(s)
would warrant better…
An aluminum rod of length L
=
1m has mass density p = 2700 kg and
Young's modulus E = 70 GPa. The rod is fixed at both ends. The exact
natural eigenfrequencies of the rod are wexact
E
=
√
ρ
for n=1,2,3,. . . .
1. What is the minimum number of linear elements necessary to
determine the fundamental frequency w₁ of the system? Discretize
the rod in that many elements of equal length, assemble the global
system of equations KU = w² MU, and find the fundamental
frequency w₁. Compute the relative error e₁ = (w1 - wexact) /w exact
Sketch the fundamental mode of vibration.
2. Use COMSOL to solve the same problem. Show the steps necessary
to find the fundamental frequency and mode of the rod. What is the
relative error using linear elements and a normal mesh?
A ball with a mass of 5.0 kg is hanging from a string and is initially at rest.
A bullet with a mass of 10.0 g and a velocity of 200.0 m/s is fired at the ball.
The bullet embeds itself inside the ball.
How high (h) do the ball and the bullet rise?
Gravitational acceleration: g=9.81g = 9.81g=9.81 m/s².
Chapter 2 Solutions
EBK 3I-EBK: WELDING PRINCIPLES & APPLIC
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