Question

Your Initials: Page 5 of 12 Problem 3 (20 pts): Heat exchanger In a supercomputer, signal propagation delays are redaced by resorting to high-density circuit arrangements which are cooled by immersing them in a special dielectric liquid. The fluid is pumped in a closed loop through the computer and an adjoining shell-and-tube heat exchanger having one shell and two tube passes. During mormal operation, heat gencrated within the computer is transferred to the dielectric fluid passing therough the computer at a flow rate of th -4.81 kg's In turn, the fluid passes through the tubes of the heat exchanger and the heat is transferred to water passing over the tubes. The dielectric fluid may be assumed to have constant properties of e 1040 J/kg K, -7.6 10 kg's m,& 0.058 Wm K and Pr 14. During nommal operation, chilled water at a flow rate ofrh-2.5 kg's and an inlet temperature of -5℃passes over the tubes. The water has a specific heat of 4200 3kg K and peovides an average convection coefficient of 10,000 W/m2 K over the outer surface of the tube Coolant Computer Pump (a) If the heat exchanger consists of 72 thin-walled tubes, cach of 10-mm diameter, and fully developed flew is assumed to exist within the tubes, what is the convection coefficient associated with flow through the tuhes? (5 pts) Page 5 of 12 Your Initials: Problem 3 (20 pts): Heat exchanger In a supercomputer, signal propagation delays are reduced by resorting to high-density circuit arrangements which are cooled by immersing them in a special dielectric liquid. The fluid is pumped in a closed loop through the computer and an adjoining shell-and-tube heat exchanger having one shell and two tube passes. During normal operation, heat generated within the computer of the heat exchanger and the heat is transferred to water In turn, the fluid passes through the tubes passing over the tubes. The dielectric fluid may be assumed to have 1040 J/kg K, v 7.65x 104 kg/s m, k 0.058 W/m chilled water at a flow rate of m 2.5 kg's and an inlet tempeaeof TS tubes. The water has a specific heat of 4200 J/ kg K and provides an ay coefficient of 10,000 W/m2 K over the outer surface of the tubes. K, and Pr 14. During normal operation, rature of Tw. 5 °C passes over the

Answer 1

No.od-tuba8トn-s-マ1.-36 = rip or otu 4-m 2223X/0 di ow all heat tran sten, cott, caput (b