Thermal Analysis of a Transport Refrigeration Power Pack Unit Using a Coupled 1D/3D Simulation Approach

Authors: A. Kospach, A. Mladek, M. Waltenberger, F. Schilling

Abstract:

In this work, a coupled 1D/3D simulation approach for thermal protection and optimization of a trailer refrigeration power pack unit was developed. With the developed 1D/3D simulation approach thermal critical scenarios, such as summer, high-load scenarios are investigated. The 1D thermal model was built up consisting of the thermal network, which includes different point masses and associated heat transfers, the coolant and oil circuits, as well as the fan unit. The 3D computational fluid dynamics (CFD) model was developed to model the air flow through the power pack unit considering convective heat transfer effects. In the 1D thermal model the temperatures of the individual point masses were calculated, which served as input variables for the 3D CFD model. For the calculation of the point mass temperatures in the 1D thermal model, the convective heat transfer rates from the 3D CFD model were required as input variables. These two variables (point mass temperatures and convective heat transfer rates) were the main couple variables for the coupled 1D/3D simulation model. The coupled 1D/3D model was validated with measurements under normal operating conditions. Coupled simulations for summer high-load case were than performed and compared with a reference case under normal operation conditions. Hot temperature regions and components could be identified. Due to the detailed information about the flow field, temperatures and heat fluxes, it was possible to directly derive improvement suggestions for the cooling design of the transport refrigeration power pack unit.

Keywords: Coupled thermal simulation, thermal analysis, transport refrigeration unit, 3D computational fluid dynamics, 1D thermal modelling, thermal management systems.

References:

[1] International Energy Agency, 2016. CO2 emissions from fuel combustion by sector in 2014, in CO2 Emissions from Fuel Combustion, IEA, 2016. In CO2 Highlights 2016.
[2] European Automobile Manufacturers’ Association (ACEA), Fact Sheet Trucks. Retrieved July, 20, 2022, from https://www.acea.auto/files/trucks_fact_sheet_ACEA.pdf
[3] European Federation for Transport and Environment. Article Road freight emissions. Retrieved July, 20, 2022, from https://www.transportenvironment.org/challenges/road-freight/
[4] Croquer, S., Benchikh Le Hocine, A.E., & Poncet, S. (2019). Numerical modelling of heat and mass transfer in a refrigerated truck trailer. 25th IIR International Congress of Refrigeration, Montréal, Canada
[5] Jeong, Jihyuk; Benchikh Le Hocine, Alla Eddine; Croquer, Sergio; Poncet, Sébastien; Bonjour, Jocelyn; and Michel, Benoit, "Numerical Simulation of the Heat Transfer in a Refrigerated Trailer Equipped with Eutectic Plates for Frozen Food Delivery" (2021). International Refrigeration and Air Conditioning Conference. Paper 2253.
[6] Kospach, A., Bäder, D. Simulation of Engine Compartment Flow with Heat Input. ATZ Worldw 121, 36–39 (2019). https://doi.org/10.1007/s38311-019-0007-5
[7] Zhang, C.; Uddin, M.; Robinson, C.; Foster, L. Full vehicle CFD investigations on the influence of front-end configuration on radiator performance and cooling drag. Applied Thermal Engineering. 130. 10.1016/j.applthermaleng.2017.11.086.
[8] Bäder, D.; Kospach, A.; Domaingo, A.: Calculation of air temperatures in the engine compartment of a vehicle. CFD-Methoden zur Simulation des Wärmeübertragungsverhaltens, Neuendettelsau, Germany, 2017
[9] Pengyu Lu, Qing Gao, Yan Wang, “The simulation methods based on 1D/3D collaborative computing for the vehicle integrated thermal management”, Applied Thermal Engineering, Volume 104, 2016, Pages 42-53, ISSN 1359-4311.
[10] Yi, H., Li, A., Sun, R., Hu, Y. et al., "1D-3D Coupled Analysis for Motor Thermal Management in an Electric Vehicle," SAE Technical Paper 2022-01-0214, 2022, https://doi.org/10.4271/2022-01-0214.
[11] Minovski, B.; Löfdahl, L.; Andrić, J.; Gullberg, P. A Coupled 1D–3D Numerical Method for Buoyancy-Driven Heat Transfer in a Generic Engine Bay. Energies 2019, 12, 4156. https://doi.org/10.3390/en12214156
[12] Francesco Fabris, Paolo Artuso, Sergio Marinetti, Silvia Minetto, Antonio Rossetti, “Dynamic modelling of a CO2 transport refrigeration unit with multiple configurations”, Applied Thermal Engineering, Volume 189, 2021, 116749, ISSN 1359-4311.
[13] Kulkarni, C. and Dwyer, H., "Modeling and Performance of Trailer Refrigeration Units with Alternative Power Systems," SAE Technical Paper 2007-01-0764, 2007, https://doi.org/10.4271/2007-01-0764.
[14] Barree, R., & M.W., C. (2004). Beyond beta factors: a complete model for Darcy, Forchheimer, and trans-Forchheimer flow in porous media. SPE Anual Conference and Exhibition. Houston.
[15] Moukalled F, Mangani L, Darwish M (2016) The finite volume method in computational fluid dynamics: an advanced introduction with OpenFOAM® and MATLAB, volu 113 of Fluid mechanics and its applications. Springer, Cham
[16] Menter, Florian & Kuntz, M. & Langtry, RB. (2003). Ten years of industrial experience with the SST turbulence model. Heat and Mass Transfer. 4.
[17] W. Sutherland, The viscosity of gases and molecular force, Philosophical Magazine 5 (1893), S. 507-531.
[18] Franzke, R.; Sebben, S.; Bark, T.; Willeson, E.; Broniewicz, A. Evaluation of the Multiple Reference Frame Approach for the Modelling of an Axial Cooling Fan. Energies 2019, 12, 2934. https://doi.org/10.3390/en12152934