Consider the fuel element of Example 5.9, which operates at a uniform volumetric generation rate of q) = 10 7 W/m3, until the generation rate suddenly changes to q2 = 2 x 107 W/m3. Use the Finite-Difference Equations, One-Dimensional, Transient conduction model builder of IHT to obtain the implicit form of the finite-difference equations for the 6 nodes, with ∆x = 2 mm, as shown in the example.

(a) Calculate the temperature distribution 1.5 s after the change in operating power and compare your results with those tabulated in the example.

(b) Use the Exp/ore and Graph options of IHT to calculate and plot temperature histories at the mid- plane (00) and surface (05) nodes for 0 < 5 t < 400 s. What are the steady-state temperatures, and approximately how long does it take to reach the new equilibrium condition after the step change in operating power?