EXPERIMENTAL DETERMINATION OF INDICATORS OF THERMAL STATE OF REFRIGERATOR CARS UNDER OPERATING CONDITIONS

For the experimental determination of the thermal state of refrigerator cars under operating conditions, a procedure for separate determination of heat and mass transfer parameters is proposed. Its peculiarity lies in the fact that conditions, methods and means of thermal tests used in the construction, operation and repair of refrigerator cars are used for the experimental determination of conductive heat transfer and tightness indicators. For separate determination of the true heat transfer coefficient and effective opening Fek, experimental conditions of the thermal process of heating air in the cargo space of the car body and measurement of the volume of air flow through leaks under constant standard overpressure of 49 Pa in the body were used. Based on the values of the true heat transfer coefficient and effective opening Fek, taking into account the thermophysical properties of cargo and using MS Excel tools, graphical dependences of changes in cargo temperature in the refrigerator car on transportation conditions are constructed. The results of the study are proposed to be used for separate determination of heat and mass transfer indicators and evaluation of thermal properties of the body sheathing of refrigerator cars under operating conditions. Based on the value of the true heat transfer coefficient and effective opening, it is possible to determine changes in cargo temperature in transportation conditions, taking into account the temperature difference of the atmospheric ai