Simulating Lubrication Flow to Predict Traction Oil Distribution Inside a NuVinci® Product
Fallbrook’s initial commercial product, a continuously variable transmission (CVT) for bicycles, now includes a rider-needs-based portfolio comprised of five group sets, city, trekking, sportive, cargo, and commercial, all available in a manual and automatic version. Cycling products are developed and managed by Fallbrook's enviolo Division headquartered in Amsterdam, the Netherlands.
Continually improving the energy efficiency of their product lies at the heart of on-going innovation at Fallbrook. The company leverages simulation to facilitate understanding of critical physical phenomena to optimize design for the right balance of energy economy at competitive prices.
Improving Oil Flow Inside the NuVinci Products
Cost-sensitive, effective, simple, robust, and efficient methods for providing lubrication internally is always challenging, as is predicting the effectiveness of a design scenario or having an effective solver/software to efficiently guide the design process in the innovation process.
Brad Pohl, Chief Engineer, Advanced Engineering, supporting the Licensing and Technology Commercialization Division at Fallbrook has been working on improving oil flow inside the NuVinci products as it affects the transmission’s efficiency, durability, power, capacity, and cost. Being able to physically see inside a complex transmission system to evaluate the design is practically unfeasible, leading Fallbrook to perform an evaluation to use the smoothed-particle hydrodynamics (SPH) method to predict traction oil distribution in the system.
Advanced CFD Simulations in the Cloud
Altair nanoFluidX™, an advanced CFD solver, optimized on the cloud to provide overnight simulation results for the most complex cases, was used by Fallbrook to simulate lubrication flow inside of a NuVinci product. nanoFluidX predicts the flow in complex geometries with complex motion, such as oiling in powertrain systems with rotating gears and shafts, using the SPH simulation method. It is specifically designed to run on Graphics Processing Unit (GPU) hardware, which offers considerable performance advantages over traditional CPU-based computing for certain applications.
Altair worked with Amazon Web Services (AWS), a secure cloud services platform, to provide an integrated solution to Fallbrook including advanced GPU hardware, high-performance computing (HPC) and the nanoFluidX software through industry-leading workload management and job scheduler, Altair PBS Professional™.
The model for simulation was generated with process-oriented finite element modeling software, Altair Simlab™. This included meshing of the system, material and property assignment, motion definition for all internal parts, and particle generation for the SPH mesh to represent the oil.