Midterm32007

# Midterm32007 - ENGR 225 December 3 2007 Name Please Check...

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ENGR 225 Name ___________________________ December 3, 2007 Please Check One Recitation: 8:30___; 10:00 ___; 1:15___ Short answer (2 pts. Each, for T/F and multiple choice circle the best answer of the choices given , fill in the blank must be completed with a meaningful word or phrase) 1. The expression below represent a balance of _______________ energy for 1-D incompressible steady flow ˙ m P 1 " + # 1 V 1 2 2 + gz 1 \$ % ( ) + ˙ W pump = ˙ m P 2 + 2 V 2 2 2 + gz 2 \$ % ( ) + ˙ W turbine + ˙ E mech , loss 2. T F The expression given in Q. 1 can also be written as P 1 g + 1 V 1 2 2 g + z 1 + h pump = P 2 g + 2 V 2 2 2 g + z 2 + h turbine , e + h L 3. The symbol ‘h’ in the expression given in Q. 2 represents a) enthalpy b) head c) height d) none of the above 4. For internal flow of velocity, V, in a pipe of length L and diameter D , h L = f L D + K L " # \$ % ( V 2 2 g therefore ˙ E mech , loss = ___________________ 5. T F Depending on what you are trying to learn, different choices for points 1 & 2 are made when applying the expressions given in Q.1 and Q.2 to a given situation. 6. When there are minor losses for flow in a pipe a) K L values must be determined b) it is equivalent to a longer pipe c) mechanical energy is being converted to heat d) all of the above e) none of the above 7. The friction factor, f, can be well approximated from the ______________ chart or the Haaland relation 1 f " # 1.8log 6.9 Re + \$ / D 3.7 % ( ) * 1.11 + , - . / 0 8. T F For external flows, there are two net forces, drag and lift, that operate in two different directions that are 90 0 apart. 9. Drag coefficients depend on a) the shape of the object b) the orientation of the object c) the velocity of the flow field d) all of the above e) none of the above because they are constants 10. A thermos bottle is a device that is designed to have a high thermal resistance for heat flow due any of the ________________ ( give a number ) modes of heat transfer. 11.

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## This test prep was uploaded on 04/08/2008 for the course ENGR 225 taught by Professor Landau during the Fall '08 term at Case Western.

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Midterm32007 - ENGR 225 December 3 2007 Name Please Check...

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