Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
A model to improve the control of the liquid injection velocity in a lazy-wave riser
Submission Author:
Matheus Pasquini , SP , Brazil
Co-Authors:
Gabriela Pereira Toledo, Matheus Pasquini, Jéssica Gonçalves, Ricardo Augusto Mazza
Presenter: Gabriela Pereira Toledo
doi://10.26678/ABCM.COBEM2023.COB2023-0970
Abstract
Engineers have been sizing single-phase hydraulic systems forever, and using system hydraulic curves to prop- erly size the pump and valves to attend to the system requirements is a part of this process. In addition, these curves can be used as a method to control the system, especially for two-phase flow. When the gas enters the system, the operational condition changes. In this way, the pump rotation and valve opening must change to ensure operational conditions. These changes are corrected manually when the gas enters the test section. The present work aims to determine a methodology to automatically determine the pump rotational speed and flow control valve aperture to attend to the required water flow rate. The methodology can be used as a control procedure incorporated into supervisory systems. Making precise and fast air and water injection control on a complex test section is challenging. Due to the air compressibility, the bubbles expand as they rise in the test section. In addition to causing variations in air and water superficial velocities, this phenomenon causes the water column to lose weight, interfering with air and water injection velocities. The water injection control system uses a numerical model to estimate the two-phase flow pressure drop in the test section and the pump head curve. The numerical data is compared with an experimental two-phase air-water flow data set. Moreover, an experimental database for single-phase flow is used to adjust the valve flow coefficient CV and the pump’s head curve CH. The system under analysis corresponds to an experimental lazy-wave riser apparatus from the Flow&Rs Lab. This apparatus has a diameter of 23.4 mm ID, a total dimensionless length of 2,142D, and a dimensionless height of 1,529D. Combining the pump head curve with the system flow coefficient makes it possible to predict the operational point in the intersections of the curves. The proposed model can predict the injection pressure of a two-phase flow with less than 15% deviation and the liquid superficial velocity with less than 20% deviation for all cases tested.
Keywords
Hydraulic system, control method, lazy-wave riser, superficial velocities, Two-phase Flow
