Refer to the Heat Transfer Engineering (Vol. 34, 2013) study of bubble behavior in subcooled flow boiling, Exercise 12.21. Recall that bubble density (liters per meters squared) was modeled as a function of mass flux (kilograms per meters squared per second) and heat flux (megawatts per meters squared) using data saved in the file.

a. Write an interaction model for bubble density (y) as a function of x1 = mass flux and x2 = heat flux.

b. Fit the interaction model, part a, to the data using statistical software. Give the least squares prediction equation.

c. Evaluate overall model adequacy by conducting a global F test (at α = .05) and interpreting the model statistics, R2a and 2s.

d. Conduct a test (at α = .05) to determine whether mass flux and heat flux interact.

e. How much do you expect bubble density to decrease for every 1 kg/m2-sec increase in mass flux, when heat flux is set at .5 megawatt/m2?