System Dynamics
3rd Edition
ISBN: 9780073398068
Author: III William J. Palm
Publisher: MCG
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Chapter 7, Problem 7.48P
A particular house wall consists of three layers and has a surface area of 30 m2. The inside layer is 10 mm thick and made of plaster board with a thermal conductivity of k = 0.2 W/(m • °C). The middle layer is made of fiberglass insulation with k = 0.04 W/(m • °C). The outside layer is 20 mm thick and made of wood siding with k = 0.1 W/(m • °C). The inside temperature is 20°C, and the convection coefficient for the inside wall surface is /i, = 40 W/(m~ • °C). The convection coefficient for the outside wall surface is ho= 70 W/(m~ • °C). How thick must the insulation layer be so that the heat loss is no greater than 400 W if the outside temperature is —20°C?
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Insulating material is used to reduce heat loss from the heating furnace walls to the room. The surface temperature of the insulating material is 100 ° C and the other surfaces 20 ° C. Allowable heat loss up to 140 W / m2 from the wall. If the thermal conductivity of the insulation material is 0.05 W / (m ° C), calculate the required thickness of insulation. insulation thickness = Answer cm
Q1/ A thick wall consists two layers of Gypsum, insulation and brick as shown in
figure below. The ambient temperature is 20 °C and heat transfer coefficient is 5
W/m2. K in the left side. The surface temperature of right side is 45 °C. find the
heat losses per meter length. What will happen if the insulation's thickness
* .increases by 25%
Gypsum k = 0.04W/m. K
T = 45 °C
h=5 W/m'. K
T. = 20 °C
5 cm
Insulation
k = 0.04W/m. K
Brick
k = 0.69 W/m. K
1. Temperatures are measured at the left-hand face and at a point 4 cm from the left-hand
face of the planar wall shown in the figure below. These temperatures are T₁ = 45.3 °C
and T* = 21.2 °C. The heat flow through the planar wall is steady and one dimensional.
What is the value of T2 at the right-hand surface of the wall?
TI
T*
4 cm
10 cm
T2
Chapter 7 Solutions
System Dynamics
Ch. 7 - Prob. 7.1PCh. 7 - Refer to the water storage and supply system shown...Ch. 7 - Prob. 7.3PCh. 7 - In Figure P7.4 the piston of area A is connected...Ch. 7 - Refer to Figure 7.1.4a. and suppose that p\ — p2=...Ch. 7 - Pure water flows into a mixing tank of volume V =...Ch. 7 - Consider the mixing tank treated in Problem 7.6....Ch. 7 - Derive the expression for the fluid capacitance of...Ch. 7 - Prob. 7.9PCh. 7 - Prob. 7.10P
Ch. 7 - 7.11 Derive the expression for the capacitance of...Ch. 7 - Air flows in a certain cylindrical pipe 1 m long...Ch. 7 - Derive the expression for the linearized...Ch. 7 - Consider the cylindrical container treated in...Ch. 7 - A certain tank has a bottom area A = 20 m2. The...Ch. 7 - A certain tank has a circular bottom area A = 20...Ch. 7 - The water inflow rate to a certain tank was kept...Ch. 7 - Prob. 7.18PCh. 7 - Prob. 7.19PCh. 7 - In the liquid level system shown in Figure P7.20,...Ch. 7 - The water height in a certain tank was measured at...Ch. 7 - Derive the model for the system shown in Figure...Ch. 7 - (a) Develop a model of the two liquid heights in...Ch. 7 - Prob. 7.24PCh. 7 - Design a piston-type damper using an oil with a...Ch. 7 - Prob. 7.26PCh. 7 - 7.27 An electric motor is sometimes used to move...Ch. 7 - Prob. 7.28PCh. 7 - Prob. 7.29PCh. 7 - Figure P7.3O shows an example of a hydraulic...Ch. 7 - Prob. 7.31PCh. 7 - Prob. 7.32PCh. 7 - Prob. 7.33PCh. 7 - Prob. 7.34PCh. 7 - Prob. 7.35PCh. 7 - Prob. 7.36PCh. 7 - Prob. 7.37PCh. 7 - (a) Determine the capacitance of a spherical tank...Ch. 7 - Obtain the dynamic model of the liquid height It...Ch. 7 - Prob. 7.40PCh. 7 - Prob. 7.41PCh. 7 - Prob. 7.42PCh. 7 - Prob. 7.43PCh. 7 - Prob. 7.44PCh. 7 - Prob. 7.45PCh. 7 - The copper shaft shown in Figure P7.46 consists of...Ch. 7 - A certain radiator wall is made of copper with a...Ch. 7 - A particular house wall consists of three layers...Ch. 7 - A certain wall section is composed of a 12 in. by...Ch. 7 - Prob. 7.50PCh. 7 - Prob. 7.51PCh. 7 - A steel tank filled with water has a volume of...Ch. 7 - Prob. 7.53PCh. 7 - Prob. 7.54PCh. 7 - Prob. 7.55P
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