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 1)The following is the energy balance for a steady state horizontally oriented NOZZLE

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 1)The following is the energy balance for a steady state horizontally oriented NOZZLE. Cross out all terms that are zero. (note that a nozzle is used to accelerate the flow velocity of a fluid)

 

 

 

 

2. What is true about entropy generation (σ)? 

            a) It is always positive in practice                    b) can be negative in practice

            c) can be negative and positive                   d) is positive in a carnot cycle

 

 

3. The (dQ/T_b) of a process is zero. What is true about the process? 

             a) It is entirely reversible               b) It is entirely irreversible

            c) It is physically not possible d) We cannot determine irreversibility

 

 

4. Which cannot be modeled as a steady state operating device ? 

            a) heat exchanger         b) gas turbine                

            c) nozzle                     d) IC engine

 

 

5. A heat engine must be in contact with at least how many thermal reservoirs ?

            a) 1                              b) 2

            c) 3                              d) 4

 

 

6. Which of the following is not an irreversibility in a heat engine? 

            a) friction                                             b) rapid compression

            c) unrestrained expansion of gas                     d) isothermal heat transfer

 

 

7. Which of the following is false about the Carnot Cycle? 

            a) theoretical maximum efficiency            b) all processes reversible   

c) more efficient than all reversible cycles      d) operates between two thermal reservoirs   

 

8. Write the Carnot efficiency in terms of T_H and T_L? 

 

9. What two things could you do to the thermal reservoir temperatures (T_L and T_H) to raise the Carnot efficiency? 

                                     

 

 

10. Combustion temperature of your car is 2000K and the surrounding air is 300K. What is the maximum efficiency this engine could achieve?