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Abstract

Maintaining railway turnout operability is crucial for ensuring railway transport safety. Electric heating of railway turnouts is a significant technical and economic issue. The classical heating is characterised by high power consumption. For this reason, research is needed to optimise the current system. This paper presents results of a numerical analysis and of experimental researches. The numerical analysis was carried out using the ANSYS software. There was conducted a numerical comparative analysis of energy loss during heating performed using two different heaters. Including the classical method and a heater thermally insulated from a rail. In the first step, heating of a working space filled with a substitute snow model was considered. The snow-covered surface area was held within the working space of the turnout. It was assumed that the snow substitute material had thermal properties approximately the same as real light snow. It was also assumed that the material is in the solid state which would not undergo a phase change. In the next step, a real snow model that included the phase change process was taken into account. The energy efficiency and heat distribution in the turnout have been analysed and compared. The experimental researches were carried out in a physical model. The results showed that the use of a contactless heater results in creating a larger area over which emitted heat affected snow in the working space. Consequently, more snow was melted around the contactless heater than the classic one. This experimental observation supported the results of the numerical analyses presented previously.

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Authors and Affiliations

Mateusz Flis
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Abstract

The non-stationary problem of temperature distribution in a circular cylindrical channel of infinite length filled with a homogeneous biomass material moving with a constant velocity in the axial direction was investigated. The heat source was a shaftless helical screw (or auger), which was heated with an electric current due to the Joule–Lenz effect and rotated uniformly around the axis of symmetry of the channel. Similar problems arise in the thermal processing of biomaterials using screw conveyor in pyrolysis and mass sterilization and pasteurization of food products. The problem is solved using the expansion of given and required functions in Fourier series over angular coordinate and integral Fourier and Laplace transforms over axial coordinate and time, respectively. As a result, the temperature field is obtained as the sum of two components, one of which, global, is proportional to time, and the other, which forms the microstructure of the temperature profile, is given by Fourier–Bessel series. The coefficients of the series are determined by the integrals calculated using the Romberg method. Based on the numerical calculations, the analysis of the space-time microstructure of the temperature field in the canal was performed. A significant dependence of the features of this microstructure on the geometric, kinematic and thermodynamic characteristics of the filling biomass and the screw was revealed.
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Authors and Affiliations

Stanisław Ledakowicz
1
ORCID: ORCID
Olexa Piddubniak
1

  1. Faculty of Process and Environmental Engineering, Lodz University of Technology, Wolczanska St. 215, 90-924 Lodz, Poland

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