Liquid-film thickness during flow boiling of pure hydrocarbons and their mixtures

Autor(es)

Baptistella, Victor Eduardo Corte ; Moreira, Tiago Augusto ; Ribatski, Gherhardt

• Tipo de documento: Artigo Científico
• Fonte: EXPERIMENTAL THERMAL AND FLUID SCIENCE; v. 144, p. 17-pg., 2023-02-24.

Resumo

The present study concerns an experimental investigation of the liquid-film thickness and void fraction during flow boiling of hydrocarbons and their zeotropic mixtures. High-speed flow images were also gathered. Exper-iments were performed for R600a, R290, R1270, R600a/R290 (70/30 M fraction) and R600a/R1270 (75/25 M fraction) in a horizontal stainless-steel tube with an internal diameter of 9.43 mm. Liquid-film thickness and flow footage were gathered in an adiabatic section, 50 mm downstream the heating section. The saturation tem-perature was kept at 5 degrees C, mass velocities ranged from 50 to 250 kg/m2s, vapor qualities from 0.07 to 0.81, and heat fluxes from 5 to 80 kW/m2. The experimental data comprehends annular flows, including results for the intermittent dryout-rewetting phenomenon. The rewetting front was found to be composed of a two-stage wave. Initially it approached the dry wall, increasing the film thickness sharply until reaching a peak. Downstream the wave-peak the liquid-film thickness and its interfacial roughness decreased smoothly. Ripples were observed on top of the rewetting wave and their velocity and amplitude decreased at the wake of the wave. Additionally, footage showed that the entrained droplets flow within intermittent clusters and not homogeneously distributed along the vapor core. The void faction was estimated based on the liquid-film thickness measurements and compared with prediction methods available in the literature. In general, reasonable agreement between experimental data and their predictions was found. (AU)

• Processo FAPESP: 16/16849-3 - Análise teórica-experimental do coeficiente de transferência de calor, perda de pressão e padrão de escoamento durante a condensação de misturas zeotrópicas de hidrocarbonetos no interior de tubos
• Beneficiário: Tiago Augusto Moreira
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 20/10923-2 - Avaliação do comportamento hidrodinâmico e dos mecanismos de transferência de calor durante a ebulição convectiva em microcanais em condições de secagem de parede
• Beneficiário: Victor Eduardo Corte Baptistella
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 18/06057-8 - Desenvolvimento e avaliação de um método para determinação experimental da espessura de filmes líquidos no interior de superfícies circulares
• Beneficiário: Tiago Augusto Moreira
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado
• Processo FAPESP: 19/08577-1 - EMU concedido no processo 16/09509-1: câmera de alta velocidade phantom V2012
• Beneficiário: Gherhardt Ribatski
• Modalidade de apoio: Auxílio à Pesquisa - Programa Equipamentos Multiusuários