Eventos Anais de eventos
COBEM 2019
25th International Congress of Mechanical Engineering
ASSESSMENT OF DIFFERENT METHODS FOR PREDICTING THE MASS FLOW RATE THROUGH ADIABATIC CAPILLARY TUBES
Submission Author:
THIAGO TORRES MARTINS ROCHA , MG
Co-Authors:
THIAGO TORRES MARTINS ROCHA, Frederico Campos, Virgilio Schettino Faria, Tiago de Freitas Paulino, Raphael Nunes Nunes de Oliveira
Presenter: THIAGO TORRES MARTINS ROCHA
doi://10.26678/ABCM.COBEM2019.COB2019-0783
Abstract
Capillary tubes are largely used as the expansion device in small scale refrigeration systems and many researches have been made to study the refrigerant flow characteristics inside them. In this paper, different strategies commonly used to depict the mass flow rate for the refrigerants CO2 (R744), R600a and R134a through adiabatic capillary tubes are reviewed, including numerical models, approximate analytical (algebraic) equations and dimensionless correlations. The predicted mass flow rates by the equations and correlations have been checked with experimental data available in the literature. Apart from the theoretical models, the algebraic equation, overall, performed better. Particularly, a correlation derived from the artificial neural network (ANN) showed better agreement for CO2, while an algebraic equation has found to be better for R600a and R134a. To verify if a better performance could be achieved, two dimensionless correlations were proposed for straight capillary tubes, being one for CO2 and other for R600a. The predicted mass flow rates by the proposed correlations showed better agreement with the experimental data when compared with all the equations and correlations previously assessed. The percentual of data points within an error band of ± 15% were 95.8% and 100%, for CO2 and R600a, respectively.
Keywords
capillary tube, adiabatic, mass flow rate, CO2, R600a
