Experimental Characterisation of Gas-Liquid Flows through a Globe and Gate Valve

Valves are mechanical devices commonly used in pipelines and pipe networks for industrial applications, including petroleum, power and process industries. In two-phase flows more complex flowing conditions occur and attention must be paid when choosing the model to predict pressure losses. To date, studies on two-phase flows through valves have been mainly devoted to safety relief valve (SRV). This paper presents the preliminary results of an experimental characterisation study of a globe and a gate valves 2” DN. The aim of the study was to investigate the flow through this type of valve, to understand the phenomena that occur inside and to improve a more general model to calculate pressure drops in two-phase flow conditions. The valve has been preliminary characterised in single phase flow obtaining good results (errors less than ±10%). The flow coefficient of the valve has been determined in order to proceed in two phase tests. Comparison between two phase flow measured data and predictive models has been considered. The Chisholm model seems to give the best agreement with the data in the observed interval for the globe valve. The best model for the gate valve seems to be the Lockartt-Martinelli modified model. Predicting pressure drops in both cases, the average error is near to zero and less than ±10%.