Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Two-phase frictional pressure drop at high saturation temperatures in a horizontal micro-scale channel
Submission Author:
Daniel Borba Marchetto , SP , Brazil
Co-Authors:
Daniel Borba Marchetto, Rémi Revellin, Gherhardt Ribatski
Presenter: Daniel Borba Marchetto
doi://10.26678/ABCM.COBEM2023.COB2023-0851
Abstract
In order to meet current and future energy demands, the efficient use of resources, as well as the progressive replacement by renewable alternatives is needed. Therefore, solutions for efficient energy generation and heat exploitation have emerged over the last years. Organic Rankine cycles (ORCs) and high temperature heat pumps (HTHPs), as well as their combination in reversible energy storage systems are promising approaches. The evaporation process in these cycles occurs at high saturation temperatures, leading to intermediate-to-high reduced pressures for most of the employed refrigerants. Thermophysical properties are deeply affected by the reduced pressure increase, resulting in thermohydraulic behaviors different from those typically verified at low temperatures. Despite the growing interest in ORCs and HTHPs, there is a shortage of flow boiling experimental studies at high temperatures, and the literature is even more scarce considering investigations with low-global warming potential (GWP) refrigerants. In this context, the present work presents an evaluation of the two-phase pressure drop for the refrigerants R1233zd(E) and R245fa flowing at saturation temperatures between 75ºC and 95°C inside a horizontal adiabatic stainless-steel tube with an internal diameter of 2 mm. Pressure gradient data are reported for mass velocities varying from 185 to 560 kg/m²s.The effects of the experimental parameters were similar to those reported for data at low pressures, in which the pressure gradient increases with the mass velocity increment and the saturation temperature reduction. The experimental results are compared against 15 prediction methods from literature and the effect of the saturation temperature on their accuracy is evaluated. Reasonable agreement was verified, with five methods predicting more than 80% of the database within error bands of +-30%. However, only six methods presented reduction of the deviations with increasing the saturation temperature, with four of them being based on the homogeneous model.
Keywords
Two-phase Flow, pressure drop, flow boilig, Microchannel, Organic Rankine Cycle
