Numerické modelování proudění chladiva ve ventilovém bloku automobilu

Abstract

The master’s thesis deals with numerical modelling of refrigerant flow in a valve block used in the automotive industry and subsequent evaluation of pressure drop between inlet and outlet of the valve block for different settings of the mathematical model. The ANSA program is used to modify the source geometry and create the computational mesh of the computational model. The numerical simulations were performed in ANSYS Fluent 2023R1 software. The introductory section is devoted to the cooling system in the automotive industry. Specifically, the function of the valve block, which allows switching of the air conditioning modes and provides comfort in the cabin or, nowadays, the increasingly used battery cooling in electric vehicles, is described. In the theoretical section, the distribution of gases from a physical point of view to ideal and real gas is characterized in detail. Furthermore, the relevant relations to the subsequent numerical calculations describing the real gases are given. Subsequently, the numerical modelling of turbulent flow is described. In the practical part, the modification of the valve block source model is described. In the next phase, a computational mesh is generated. The next step was to define a mathematical model of the flow, which is then applied to a real valve block. The numerical solution is performed in ANSYS Fluent 2023R1. Numerical calculations are performed for different definitions of the physical properties of the refrigerant and different settings of the mathematical model Numerical simulations are also performed for the refrigerant R1234yf. The last topic is devoted to a complex numerical simulation of refrigerant flow through a valve block with heat transfer by conduction and convection. Pressure drops and basic flow parameters such as velocity, pressure, temperature, etc. are evaluated in detail in the post-processing.