2. The University of Memphis Using MERLOT Learning Objects in Mechanical Engineering Dr. Edward H. Perry Department of Mechanical Engineering The University of Memphis

3. Using MERLOT Learning Objects in Mechanical Engineering  Engineering Thermodynamics  Gas Dynamics

4. The University of Memphis Steam Tables vs Online Steam Calculator

5. The University of Memphis Steam Turbine  Typical Problem: Determine the enthalpy for steam leaving an ideal steam turbine at 1 psia if the steam enters at a pressure of 1500 psia and a temperature of 1000 o F.

6. The University of Memphis Steam Table Approach - Step 1  Using conventional superheated steam tables, we find that at 1500 psia and 1000 o F, the entropy s of the steam at the turbine inlet is: s 1 = 1.6001 Btu/lbm-R

7. The University of Memphis Steam Tables - Step 2 Ideal Steam Turbine => Entropy remains constant (i.e., s 2 = s 1 ) Using the Saturation Tables, we find the quality of the steam at the turbine exit (p 2 = 1 psia, s 2 = s 1 = 1.6001 Btu/lbm-R) is: x 2 = (s 2 - s f )/s fg = (1.6001 - 0.13266)/1.8453 = 0.795 Thus, the enthalpy at the exit is: h 2 = h f + xh fg = 69.74 + (0.795)(1036.0) = 893.4 Btu/lbm

8. The University of Memphis Online Calculator Approach www.mathpad.com www.mathpad.com Inlet Conditions p 1 = 1500 psia T 1 = 1000 o F Thus, s 1 = 1.60037… Btu/lbm-R Exit Conditions p 2 = 1 psia s 2 =s 1 = 1.60037... Thus, h 2 = 893.7 Btu/lbm “Ideal” Turbine => Entropy remains constant (s 2 =s 1 )

9. The University of Memphis Determining Exit Conditions in a Rocket Nozzle Typical Problem: Determine the Mach number and speed of the combustion products leaving a converging-diverging nozzle with an area ratio of 50:1. Assume a specific heats ratio g of 1.20 for the gases.

10. The University of Memphis Traditional Approach - Calculations This non-linear equation is not only messy. It cannot be solved directly. A trial-and- error root-finding approach must be used.

11. The University of Memphis Traditional Approach The results of one such iterative method are shown below and indicate that the correct answer is approximately M = 4.3958

12. The University of Memphis Online Calculator Approach http://www.aoe.vt.edu/~devenpor/aoe3114/calc.html http://www.aoe.vt.edu/~devenpor/aoe3114/calc.html Using the calculator, we immediately find the Mach number to be 4.3958

13. The University of Memphis Nozzle Simulator http://www.grc.nasa.gov/WWW/K-12/airplane/ienzl.html http://www.grc.nasa.gov/WWW/K-12/airplane/ienzl.html

14. The University of Memphis Thanks Merlot!