Air initially at 120 psia and 500o F is expanded by an adiabatic turbine to 15 psia and 200o F. Assuming air can be treated as a
n ideal gas and has variable specific heat. a) Determine the specific work output of the actual turbine (Btu/lbm). b) Determine the amount of specific entropy generation during the irreversible process (Btu/lbm R). c) Determine the isentropic efficiency of this turbine (%). d) Suppose the turbine now operates as an ideal compressor (reversible and adiabatic) where the initial pressure is 15 psia, the initial temperature is 200 o F, and th
1 answer:
Answer:
a. Wa = 73.14 Btu/lbm
b. Sgen = 0.05042 Btu/lbm °R
c. Isentropic efficiency is 70.76%
d. Minimum specific work for compressor W = -146.2698 Btu/lbm [It is negative because work is being done on the compressor]
Explanation:
Complete question is as follows;
Air initially at 120 psia and 500oF is expanded by an adiabatic turbine to 15 psia and 200oF. Assuming air can be treated as an ideal gas and has variable specific heat.
a) Determine the specific work output of the actual turbine (Btu/lbm).
b) Determine the amount of specific entropy generation during the irreversible process (Btu/lbm R).
c) Determine the isentropic efficiency of this turbine (%).
d) Suppose the turbine now operates as an ideal compressor (reversible and adiabatic) where the initial pressure is 15 psia, the initial temperature is 200 oF, and the ideal exit state is 120 psia. What is the minimum specific work the compressor will be required to operate (Btu/lbm)?
solution;
Please check attachment for complete solution and step by step explanation
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Shearing stresses are the stresses generated in any material when a force acts in such a way that it tends to tear off the material.
Generally the above definition is valid at an armature level, in more technical terms shearing stresses are the component of the stresses that act parallel to any plane in a material that is under stress. Shearing stresses are present in a body even if normal forces act on it along the centroidal axis.
Mathematically in a plane AB the shearing stresses are given by
Yes the shearing force which generates the shearing stresses is similar to frictional force that acts between the 2 surfaces in contact with each other.
