Chapter 8, Problem 8.64P

To maintain pump power requirements per unit flow rate below an acceptable level, operation of (he oil pipeline of Problem 8.63 is subject (o the constraint that the oil exit temperature $T_{m,o}$ exceed $\text{11}0°\text{C}$ . For (he values of $T_{m,i},T_s,D,t_i,z,L$ , and $k_i$ prescribed in Problem 8.63. operating parameters that are variable and affect $T_{m,o}$ are the thermal conductivity of the soil and the flow rate of the oil. Depending on soil composition and moisture and the demand for oil, representative variations are $0.25\le k_s\le 1.0\text{W/m}\cdot \text{K}$ and $250\le m_0\le 500\text{kg/s}$ . Using the proper ties prescribed in Problem 8.63. determine the effect of the foregoing variations on $T_{m,o}$ and the total heat rate q. What is the worst case operating condition? If necessary, what adjustments could be made to ensure that $T_{m,o}\ge 110$ °C for the worst case conditions?