EXPERIMENTAL STUDIES ON PRESSURE DROP CHARACTERIZATION OF CURVED TUBE SECTIONS IN LAMINAR FLOW REGIME

Abstract

Flow measurement is an important task in many engineering applications. There are various methods available for flow measurement like differential pressure flow meters, displacement flow meters, and velocity flow meters etc., which indirectly measure the mass flow rate of a fluid. Whereas direct mass flow measurement devices like Coriolis Mass Flow Meter (CMFM) are, nowadays, gaining attention due to high accuracy and reliability. In practice, most of the times, flowing fluid is quite often turbulent and hence, the studies on flow field had been around turbulent flow regime. Generally, higher velocities have been found in the turbulent regime. However, as the fluid viscosity increases there can be increase in the mean velocity in the proportion such that the flow still remains laminar. The performance of CMFM is found to be deviated in this flow regime leading to underestimation of the flow rate as reported by Kumar and Anklin [1]. Bobovnik et al. [2] carried out numerical simulations to predict the performance of shell type Coriolis flow meter for a range of Re with the tube of two different aspect ratios. The velocity profile effect was presented in terms of anti-symmetric fluid forces which resulted in a loss of sensitivity at low flow rates. Kutin [3] presented a numerical study on the velocity profile effects for two straight tube configurations, one operating in a beam-type mode and other in a shell-type mode and reported that in both the cases, the meter sensitivity was affected. The author highlighted the intensive deviations in flow meter sensitivity at low Re. This can lead to a substantial economic loss in Petroleum industries. The literature review of CMFM in the laminar region has highlighted the development of secondary flow phenomenon in curved tube sections leading to under-read the meter in this region. The issue of under reading in case of CMFM needs attention and thereby remedial solution as an outcome of research.