Chapter 1, Problem 1.24P

A cartridge electrical heater is shaped as a cylinder oflength $L=200\text{mm}$ and outer diameter $D=200\text{mm}$ . Under normal operating conditions, the heater dissipates2 kW while submerged in a water how that is at 20°Cand provides a convection heat transfer coefficient of $h=5000{\text{W/m}}^{\text{2}}\cdot \text{K}$ . Neglecting heat transfer from theends of the heater, determine its surface temperature $T_s$ .If the water flow is inadvertently terminated while theheater continues to operate, the heater surface isexposed to air that is also at 20°C but for which $h=50{\text{W/m}}^{\text{2}}\cdot \text{K}$ . What is the corresponding surface temperature? What are the consequences of such an event?