Calculation method for the overall heat-transfer coefficient of a technical transport superstructure for perishables in traffic

Abstract

High quality and safe transportation of perishable food cargo (PFC) by railway transport is impossible without knowledge of the heat engineering parameters of the technical transport (TT) used for transportation. Due to constant increase of requirements for PFC quality safety during transportation, the task of regular inspection and survey of TT is imperative. During transportation of (PFC by technical transport (TT) in the “thermos” mode, their quality is maintained for a limited period, that directly depends on the value of the overall heat transfer coefficient (coefficient K) of the TT superstructure. Concurrently, the use of coefficient K calculated based on the average values measured during the heat engineering tests (electric power, air temperature, average area of the TT superstructure) without considering significant fluctuations like conducting the tests without putting the TT into the specialized isothermal enclosure, enhances the risk of deterioration of the transported cargo quality transported during such transport.The proposed technique allows companies conducting heat engineering tests to calculate the coefficient K value measured using the method of internal heating without using a specialized isothermal enclosure. This is achieved by adding an expanded uncertainty on the measurement of coefficient K in its final value. The method was tested from 2016–2018 in the control process of the heat engineering parameters of the “thermos” cars. The results confirmed that all significant components of measurement uncertainties are considered in calculating the final value of coefficient K.Application of the proposed technique ensures safeguarding the quality and safety of transported goods during development of the PFC transportation conditions in the “thermos” mode connected with calculation of the cargo transportation time-limit.