FLOW-3D offers simulation solutions to many of the challenges in the automotive industry, including transient flow dynamics, (both free-surface and confined), thermal energy transfer in fluids and solids, phase change, 6-degrees of freedom motion of solids and a coupled finite element solver for mechanically and thermally induced stresses.
Traditional areas of interest for the automotive industry include: fuel tank sloshing, underhood thermal management and spray control, early fuel shut-off during fill, degas bottles, fluid resistance of powertrain components, and casting of automotive parts.
Fuel tanks in automotive vehicles are crucial for safely storing fuel. They also ensure constant and adequate supply for various operating loads of a vehicle in motion. The tanks can be complex in shape to ensure compact packaging with vehicle chassis design and body panels. When the vehicle accelerates through driving conditions, the fuel sloshes within the tank triggering a challenge to fuel level gauges, pressure and delivery systems. Fuel filling is critical at pumps where the vapor compressibility in the tank can cause undesired early shutoff of filling nozzle. In addition, static electricity can be conveyed into the fuel tanks resulting in rise of electric potential within fuel system. FLOW-3D helps simulate these complex multi-phase, multi-physical, transient scenarios to aid fuel system design and improvement.
Other analysis capabilities include:
- An electrostatic model that can capture a charge distribution with time
- Fuel level indication using the Moving Objects model with 6 degrees of freedom to capture float variations
- Fuel line pressurization
- Optimal location of vents
Early Fuel Shut-off
FLOW-3D is used here to analyze two fuel filling scenarios. In the better case (top animation), fuel is filled through the wider line while air vents through the narrow line without backfill. However, in the other case (bottom animation), fuel fills through the narrow vent line due to placement of the pump nozzle and causes a backfill resulting in a shut off/spill scenario. FLOW-3D’s TruVOF technique allows quick and accurate transient simulations of multiphase fuel flow. FLOW-3D can also model the sloshing of fuel tanks and efficient fuel indication system designs. This simulation shows the comparison of designs using FLOW-3D where the top animation shows a design without back flow issues. The bottom animation has a back flow problem in the vent line.
Fluid resistance is an area of interest to designers of rotating systems in fluid. FLOW-3D has a fully coupled, 6-degree of freedom model that can simulate numerous objects all moving in conjunction. The model calculates and outputs resistive data in terms of total resistance, pressure resistance and viscous resistance. The Moving Objects model that enables this capability is fully parallelized for efficient simulation times. Also, the way FLOW-3D‘s numerics are applied means that object collisions and efficiency of motion are optimized. Finally, many types of constraints can be assigned including, axial and rotational constraints, applied forces and torques, collisions based on friction and a coefficient of restitution, and tethering with springs or ropes.
FLOW-3D‘s porous media model is well suited for simulating flow in filters. There are a number of drag formulations which can be applied to determine optimal designs, which will capture particulates well and minimize drag. Particles can be introduced with a range of sizes or mass to determine the trajectory of the particulates.
Data output that can be analyzed includes velocity profiles, residence time, distance traveled by fluid, strain rate, and stream lines. It is also easy to extend the capability to predict clogging and the resulting additional drag through customization. Flow Science offers a number of numerical routines available for modification.
Degas bottles are crucial components of automotive engine coolant systems, used to de-aerate the coolant fluid during its passage. These bottles consist of several chambers and have a complex geometry based on underhood compactness and vehicle design. It is important to study air entrainment, settling and sloshing behavior of coolant fluid during vehicle acceleration.
FLOW-3D is used to analyze the multiphase behavior of sloshing coolants within a running automotive coolant system. Coolant fluid within each chamber through time can be tracked and any interference with either the cap or vents can be analyzed. The simulation below shows transient velocity magnitude contours and air entrainment during an active filling and sloshing simulation.