During the operation of milk pipelines of milking equipment, milk residues of various properties, composition and thickness are formed on the internal surfaces of the pipeline. Their presence leads to an increase in bacterial contamination of milk. If all the necessary conditions for keeping livestock buildings are met, the main share of the mechanical and bacterial contamination of milk is formed due to insufficiently washed milking machine equipment. Therefore, to improve the quality of flushing, we propose to use an injector, which performs the function of periodically supplying air to the volume of the milk line, while creating significant fluctuations in the vacuum pressure and, as a consequence, controlled water hammer which should be controlled using automated systems of milking equipment. The aim of the study is to carry out a numerical simulation of the operating modes of the system for flushing milk pipelines of milking equipment with an air injector and determine their rational values . As a result of numerical simulation of the process of washing the milk line of the milking machine using the injector in the software package STAR-CCM +, the dependences of the rate of change of pressure and the change of the thickness of the layer of milk on the wall of the milk line at different values of its diameter from the working vacuum pressure, the duration of the injection stroke and the injection stroke the duration of the air injector pause. Solving the compromise problem, which reduces to minimizing the thickness of the milk layer on the wall of the milk pipeline and the rate of change of pressure for various values of the diameter of the milk pipeline, the corresponding rational parameters of the injector operating modes are obtained.
Keywords: milking unit, washing system, washing solution, multiphase medium, numerical simulation.