Question

4.32: Cooling method for gas turbines. Refer to the Journal of Engineering for Gas Turbines and Power (January 2005) study of a high-pressure inlet fogging method for a gas turbine engine, Exercise 4.13 (p. 188). Recall that you fit a first order model for heat rate (y) as a function of speed (x1), inlet temperature (x2), exhaust temperature (x3), cycle pressure ratio (x4), and air flowrate(x5) to data saved in the GASTURBINE file.

(a) Researchers hypothesize that the linear relationship between heat rate (y) and temperature (both inlet and exhaust) depends on air flow rate. Write a model for heat rate that incorporates the researchers’ theories.

(b) Use statistical software to fit the interaction model, part a, to the data in the GASTURBINE file. Give the least squares prediction equation.

(c) Conduct a test (at α = .05) to determine whether inlet temperature and air flow rate interact to effect heat rate.

(d) Conduct a test (at α = .05) to determine whether exhaust temperature and air flow rate interact to effect heat rate.

(e) Practically interpret the results of the tests, parts c and d.

Answer 1