Study On Mechanism Modeling Of Stratified Flow Based On Slotted Orifice

Slotted orifice is a new type of flow measuring element for gas-liquid two phase flowmeasurement. Comparing with the standard orifice, slotted orifice has a lot of advantages, e.g.its differential pressure signals are steady, it has a low requirement on the straight pipesupstream and downstream, there is no accumulation of liquid phase in the upstream. Based onthe flow mechanism of gas-liquid two phase flow passing the slotted orifice, The slottedorifice measurement model for stratified flow is presented.1. Experiment data de-noising by using low-pass filter or wavelet method. Choosingunbiased likelihood method according to the de-noising effect. This make a preparation forthe model validation.2. By analyzing the local resistance of the slotted orifice, the total pressure drop ismainly consist of the frictional pressure drop and the acceleration pressure drop, which can becalculated by the momentum conservation equations and the energy conservation equations.Study the key parameters in the model and select the void fraction model.3. The stratified flow pressure drop model is tested by the experiment data. The meanrelative error of the slotted orifice with beta ratio0.75is6.45%. The double slotted orificemeasurement model is solved by a modified void fraction model for the slotted orifice withbeta ratio0.5. The mean relative error of gas phase and liquid phase are7.5%、36.63%.