Cooling method for gas turbines: Write a complete second-order model for heat rate.
a) Model A: HR = k1(T1 - T2) + k2(T1² - T2²)
b) Model B: HR = k1(T1 - T2) + k2(T1² + T2²)
c) Model C: HR = k1(T1 + T2) + k2(T1² - T2²)
d) Model D: HR = k1(T1 - T2) - k2(T1² + T2²)