Determination of loop flow rate in an external air–lift loop with middle riser using drift flux model

B Tulja Lal; P Sai Varun; K Anusha; G Raga Reddy; G K Pujari; N M Rao

Volume : VII, Issue : XII, December - 2017

Determination of loop flow rate in an external air–lift loop with middle riser using drift flux model

B Tulja Lal, P Sai Varun, K Anusha, G Raga Reddy, G K Pujari, N M Rao

Abstract :

External Air–Lift loop consists of a single riser in the middle and two down comers on either sides of the riser connected to the separator tank at the top and a horizontal pipe at the bottom. The reliable prediction of hydrodynamic behaviour is essential for the safe design of Multi–External Air–Lift Loop (ALL). A theoretical model based on the drift flux model was developed to predict the loop flow rate. In order to validate the developed model, a series of experiments were performed on an external ALL to measure the loop flow rate in two down comers and pressure drop in riser. Theoretically liquid circulation rate was predicted with drift flux model by using Jowitt void fraction correlation and Filiminov et al. void fraction correlation coupled with the Friedel two phase multipliers. Experimentally liquid circulation rate in the two downcomers is measured by using ultrasonic flow meter and the predicted results from drift flux model was found to be in excellent agreement with the experimental results. The water coming into the riser increased which is the result of increase of loop flow rate by introducing the two downcomers to External Air–Lift loop. < clear="all" style="page–eak–before:always; mso–eak–type:section–eak" />