A two phase flow nonlinear parameter estimation for capillary tube-suction line heat exchanger

• Autor(a) principal: Barbazelli, Marcos Rogério [UNESP]
• Data de Publicação: 2001
• Outros Autores: Seixlack, André Luiz [UNESP], Aparecido, João Batista [UNESP]
• Tipo de documento: Artigo de conferência
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/66736
• topic: Capillary tube; Parameter estimation; Two-phase flow; Capillary tubes; Condensation; Differential equations; Enthalpy; Evaporators; Gravitation; Heat conduction; Refrigeration; Surface tension; Temperature distribution; Thermal conductivity; Torque; Two phase flow; Vapors; Pressure gradients; Thermostatic valves; Heat exchangers

Here we present two-phase flow nonlinear parameter estimation for HFC's flow through capillary tube-suction line heat exchangers, commonly used as expansion devices in small refrigeration systems. The simplifying assumptions adopted are: steady state, pure refrigerant, one-dimensional flow, negligible axial heat conduction in the fluid, capillary tube and suction line walls. Additionally, it is considered that the refrigerant is free from oil and both phases are assumed to be at the same pressure, that is, surface tension effects are neglected. Metastable flow effects are also disregarded, and the vapor is assumed to be saturated at the local pressure. The so-called homogeneous model, involving three, first order, ordinary differential equations is applied to analyze the two-phase flow region. Comparison is done with experimental measurements of the mass flow rate and temperature distribution along capillary tubes working with refrigerant HFC-134a in different operating conditions.