WORLD-LEADING SIMULATION OF AEROSPACE TRANSMISSIONS (HEATSSIM)

Transcription

1 WORLD-LEADING SIMULATION OF AEROSPACE TRANSMISSIONS (HEATSSIM) Romax Technology Ltd (Lead), Ansys, University of Nottingham Project details: Transmissions are an essential sub-system in any aerospace application. The transmission system is central to the design and operation of any helicopter, either for commercial or military use, and the next generation of ultra-high bypass gas turbines for aircrafts have a transmission at the core. In engineering design, progress requires pushing the boundary of performance, yet this cannot be achieved within sensible time of cost limits through making and breaking prototypes. Simulation is the key. This project set out to develop an optimised design and simulation process for aerospace transmissions. There is a lot going on in a transmission which needs to be simulated they deform under load, make noise, they heat up, oil gets thrown around by meshing gears; too much oil and the transmission is inefficient, too little and it overheats. They must not fail. HEATSSIM (Holistic Engineering Approach to Thermal and Structural Simulation) was a 2 ½ year, 1.0m project led by Romax Technology, a UK-based company that leads the world in the simulation of transmission systems. To augment their existing capability, Romax linked their mechanical understanding of transmissions with the thermal/fluid capabilities of Ansys, a global leader in generalist simulation software. Specialist application knowledge was provided by the University of Nottingham. The target was not just to include all the important physical behaviours, but to link them together, providing an efficient and productive process that guides the engineer to an optimised design. Table 1: Summary of the project grant details Project Funding Lead Partner No. of Partners Total: 1.0m HEATSSIM Grant: 0.5m Company Name 3 Partner Composition 1 Large company, 1 SME, 1 Academic Duration Table 2: Summary of the project focus areas ATI Value Streams ATI Enablers ATI Attributes Strategic Horizon Whole Aircraft Aerodynamics Safety x Secure x Structures x Manufacturing Cost x Exploit Propulsion x Materials Environment x Position Systems x Infrastructure Fuel Burn Process and Tools x Operational Needs Passenger Experience 1 Copyright Aerospace Technology Institute. 2017

2 Technology Achievements: All the key physical behaviours of the transmission were simulated, including: By Romax Technology o Deflection of the transmission under load o Fatigue of the gears and bearings o Heat generation at the gears and bearings due to friction o Heat dissipation in the transmission and subsequent thermal expansion o Noise generation of the meshing gears o Efficiency of the transmission o Response of the transmission to shock loads By University of Nottingham o Oil flow within the transmission Simulation of an Aerospace Transmission involves many different physical phenomena This was only the start; many of these behaviours interact, one causing or influencing another, for example: Deflections (e.g. of a shaft) change the alignment of gears which worsens fatigue, noise and heat generation Heat generation is an input to heat dissipation and thus thermal expansion Oil flow affects heat dissipation and thus thermal expansion Thermal expansion is added to the loaded deflections of transmission Test cases showed that these influences were important. A case study carried out by Romax using the transmission designed for the Renault Zoe, in the project ODIN (Optimised drivetrain by Integration) funded by the EU s 7 th Framework Programme), showed that including the thermal effects significantly changes the misalignment of the gears, which will affect the transmission s noise, efficiency and durability. As with most transmissions, these influences were not considered in the design process. The knowledge obtained from an automotive example is directly related to an aerospace application. 2 Copyright Aerospace Technology Institute. 2017

3 Studies showed that temperature distribution can significantly affect the structural behaviour of a transmission However, this presents another challenge; If all these influences are important, how can an engineer properly predict how the transmission will respond without being overwhelmed by the different crossinfluences. In short, how do we avoid Paralysis by Analysis? The solution was to identify which factors are most important, and which calculations can be run quickest and with the simplest model of the transmission, then to consider these factors earlier in the design process. Design consists of a down-selection process, starting from many options, narrowing to a few, then a final selection. It is a bit like Shall we holiday at the beach or in the mountains? Spain or Greece? Which island? Which resort/hotel? etc. At each stage we study different aspects and at different levels of detail. Thus, Romax developed a unique multi-fidelity design process. The most influential, simple and fast methods are used for the initial investigation, transitioning to more detailed methods when confirming the performance of the final design. All the key performance considerations are included, and each method uses a single definition of the transmission so that all analyses are up to date at all times. Productivity requires that all these influences are combined into an efficient Design and Simulation Process 3 Copyright Aerospace Technology Institute. 2017

4 Central to this process is a workflow developed by Ansys which links the software products RomaxDESIGNER and ANSYS Fluent. Believed to be the first of its kind in the world, it aims to democratise the use of advanced simulation tools by allowing a greater range of engineers to carry out these tasks, reducing the burden on the experts. RomaxDESIGNER can transfer designs to ANSYS Fluent for fluid simulation) through an automated workflow Table 3: Summary of the technology achievements Project Performance Improvements TRL Progression Simulating impact of temperature distribution on transmission structure HEATSSIM Automated workflow between RomaxDESIGNER and ANSYS Fluent 3 tech s to TRL6 A multi-physics design and simulation process for transmissions Economic Impact: Romax Technology and Ansys are software vendors whose products are sold across the globe and across many industries (aerospace, automotive, marine, locomotive, off-highway etc.). As well as creating new opportunities for a software product it will help secure the commercial positions of the existing software solutions that it links. Romax Technology, is headquartered in the UK with software development and consultancy services being centred in Nottingham. Ansys has a significant presence in the UK including engineering services. Income will be derived from software licenses and engineering services. Much of this revenue takes the form of renewing leases, indicating revenue streams that will last many years. Both parties tools are currently used by major aerospace companies. This project will allow these tools to be linked by these major clients, improving their productivity in new product development and reducing project risk. Upon seeing the results of the effect of temperature distribution on gear mesh misalignment, a Project Engineer from a major aerospace company working on a critical transmission design project said, we are not including this influence currently in ***** (our project); I really think we should. An additional area of economic impact is in the automotive sector, where highly integrated electric drive systems are being designed. Thermal management is key to achieving the high efficiency and power density demanded in electric vehicles. The transmission simulation capability developed through 4 Copyright Aerospace Technology Institute. 2017

5 HEATSSIM has strong cross over applications into the automotive sector to address these challenges. Results of this project has already been presented at aerospace conference (European Rotorcraft Forum, 2017) plus cross-industry software user conferences in Europe, US, Japan, Korea and China. Commercial engineering services contracts have already been signed and delivered and more are under discussion. This is an exciting addition to our technology portfolio and we see excellent prospects for the future said Romax Chief Technical Officer Barry James, Romax has been first to market on other technologies such as simulation of gearbox noise and this has brought in steadily rising revenue for many years. We expect this technology to have similar success and longevity. Finally, there are social and environmental impacts. The project facilitates democratisation of an aspect of advanced engineering simulation. Additionally, whether we are looking at new aerospace propulsion concepts, electric passenger cars or the many other areas of electro-mechanical drives, this project assist the goals of CO 2 reduction by enabling more optimised and efficient transmission systems Table 4: Summary of the economic impact Project Value created Employment Previous technologies have yielded Jobs created: 2, more in future HEATSSIM > 20m over a 20 year period Safeguarded: 2, more in future Next Steps: As has been stated, commercial activities have already started. Both Ansys and Romax will commercialise this technology across all territories and all industries, including aerospace and especially automotive, where the design of electrified drivelines places a strong demand on this technology. In aerospace, new challenges are appearing that will require this technology. The design of new, ultrahigh bypass ratio gas turbines is placing the auxiliary drive gearboxes in unusual and thermally-challenging locations. New materials such as composites, whose properties are sensitive to heat, are being studied. Finally, plans to move towards More Electric Aircraft, with their power dense, electrified, distributed propulsion systems will require thermal management that is optimised; a task only achieved through a pragmatic and efficient simulation process, such as that developed in this project. Engineering has been asked to tackle enormous environmental challenges. This project sits squarely at the centre of tackling these challenges, in aerospace and other industries, today and far into the future. [ENDS] 5 Copyright Aerospace Technology Institute. 2017