Title:	Multidisciplinary simulation of flows, acoustics, structures and coupled FSI using CFD, FEA and LBM
DNr:	SNIC 2021/5-285
Project Type:	SNIC Medium Compute
Principal Investigator:	Huadong Yao <huadong.yao@chalmers.se>
Affiliation:	Chalmers tekniska högskola
Duration:	2021-07-01 – 2022-07-01
Classification:	20306
Homepage:	https://huadong.m2.chalmers.se/projects/
Keywords:

Abstract

This project is proposed as an extension of three projects that will be ended by the end of June, 2021. For the convenience of project management, these three projects are merged and will be considered as three major branches of this new project. Brache 1 -- acoustics: Wind noise becomes dominant as automobiles driving at cruise speed (80-90 kph). A quiet driver environment is a contributing sales motivation in the sense of comfort, safety and quality. Wind noise is almost always undesired, in contrast to engine noise which in some cases provides useful feedback to the driver. Over time the engine noise has been reduced, and the relative wind noise contribution has increased. Wind noise will become even more pronounced in the future in regard to hybrid or fully electric propulsion. In product development, a predictive numerical method for wind noise is needed. For engine noise, there are well-established tools and methods available. However, when it comes to wind noise, many areas of CAA (Computational Aero-Acoustics) are still active research areas, meaning that methods and tools are not so established and mature as those for aerodynamics. With a fundamental understanding of noise source generation, it will be possible to develop a set of design guidelines and virtual methods that can be used to evaluate, predict and optimize the behavior of typical exterior shapes used on automobiles. The techniques will be beneficial in the product development process, to predict problems already before a product has been built and reduce physical testing. The goal is to develop a fast and robust approach for predicting the dominant noise sources in the exterior flow field. This project branch aims to establish a fundamental understanding of how noise sources are created by external turbulence around automobile bodies and how the noise sources depend on geometrical complexity and flow speeds. Branch 2 -- flow dynamics: The introduction of UHBR engines poses new challenges to optimal nacelle design, both in geometry and in location. In response to the topic CfP09 CS2-LPA-01-67, the IVANHOE project will address this challenge, resulting in a new multi-fidelity optimization method, validated by advanced wind tunnel experiments. A consortium of an SME, an industry, an R&D institute, and 3 universities with complementary skills will produce this result in close coordination with the topic manager in 36 months, asking for a grant of € 3 514 834. Coordinator CTH will provide the design envelope and safeguard thrust/drag performance, HIT09 and UNIPD will jointly optimize a rapid design loop to down select options. TUB will validate the resulting design options with a high fidelity CFD code, complemented by a high fidelity wind tunnel experiment of a Deharde powered nacelle model in DNW’s High-Speed Tunnel. The project branch will advance the state of the art in nacelle design by smart use of various fidelity level aerodynamic modeling tools enabling fast iterations and down selection of nacelle geometries and locations. Wing/nacelle interference will be taken into account. This method will be validated by wind tunnel experiments with new and advanced wind tunnel models and measuring techniques. The result of the nacelle optimization for a UHBR installation on the Common Research Model will be delivered in full compliance with the call. Moreover, IVANHOE will provide an improved design method, tools, and facilities for use by the European aviation industry for future aircraft projects, unlocking the full potential of CO2 reduction of UHBR engines while increasing competitiveness by reducing costs for design and testing. Branch 3 -- MDO (multidisciplinary design optimization) and FSI (fluid-structure interaction): Electrification of vehicles has a good momentum today. However, the energy consumption of electrified vehicles is not very much in focus, instead, in-efficient electrified vehicles are appreciated on the cost of more energy-efficient ICE vehicles. There is talk about a ‘nordic energy mix’, but still almost every single extra kWh of electric energy put in an electrified vehicle in Scandinavia must be generated by fossil fuels. This needs to come to an end when electrified vehicles become more and more common. In a recently conducted research project [Vehicle – Energimyndigheten project 41213] it was identified that the gearbox has the same loss as the electrical machine. The gearbox is usually a two-stage gearbox, with a gear ratio of 8-12. If a single-stage gearbox could be used, the efficiency would go up, however, then the electric machine becomes larger. No gear at all gives best efficiency, but a very large electrical machine. In principle, 1500 rpm at top speed with a power of 100-150 kW is what is needed. The purpose of this project branch is to optimize the electric machine-gear package to find a system solution that has the highest efficiency, but still reasonable size. The hypothesis is that by a careful design of the gearbox, selection of more viscous oil, but still suitable to maintain the lifetime of the gear in combination with an adapted machine design will lead to important loss savings in the transmission of an electrified vehicle. A set of base electrical machines will be identified, focusing on environmentally sound machines without rare earth metals. For a given requirement (100 kW) veracious electric machines will be designed and the outcome will be communicated to the Fluid Dynamics division. Based on the feedback from their side modifications will take place.