The paper investigates the performances of a particular kind of evaporative system operating under natural circulation dictated mainly by heat input. Those devices are based on the principle of closed loop two-phase thermosyphons and they can operate both as pumpless loops/two phase loops (TPL) and as bubble pumps (BP). After an analysis of the literature about similar devices, based on natural circulation and a preliminary theoretical analysis, the paper proposes an experimental investigation using a special facility (test rig). The performance of the device has been analyzed using different working fluids: water, R11, R113, R141b and FC72. The influence of the geometric dimension of the lift tube, of the fluid and of the volume of working fluid in the device, at atmospheric pressure is considered. The analysis limited to tubes with diameters of 5 and 10 mm, height 1 m and heat input variable from 0 to 200 W, confirms the importance of measuring mass flow rate in a natural circulation loop and the connection between heat and mass transfer
Heat Transfer and Flow Pattern in Two-Phase Loops: an Experimental Investigation
FRANCO, ALESSANDRO
2008-01-01
Abstract
The paper investigates the performances of a particular kind of evaporative system operating under natural circulation dictated mainly by heat input. Those devices are based on the principle of closed loop two-phase thermosyphons and they can operate both as pumpless loops/two phase loops (TPL) and as bubble pumps (BP). After an analysis of the literature about similar devices, based on natural circulation and a preliminary theoretical analysis, the paper proposes an experimental investigation using a special facility (test rig). The performance of the device has been analyzed using different working fluids: water, R11, R113, R141b and FC72. The influence of the geometric dimension of the lift tube, of the fluid and of the volume of working fluid in the device, at atmospheric pressure is considered. The analysis limited to tubes with diameters of 5 and 10 mm, height 1 m and heat input variable from 0 to 200 W, confirms the importance of measuring mass flow rate in a natural circulation loop and the connection between heat and mass transferI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
