CFD AnalysisCFD Analysis

� 20 mm inlet diameter (19 mm for E85) creates choked flow conditions,

limiting total mass airflow to engine

� Required by competition rules

� Keeps engine power at a safe level for competition

Intake Restrictor

� Design goal is to minimize loss coefficient through restrictor geometry to

allow maximum airflow into engine

� Supersonic Converging – Diverging Nozzle Geometry

� Expand out diverging section to allow for proper shock development to minimize loss

coefficient

� Keep diffuser angle low enough to avoid potential flow separation

� Keep overall length low to reduce viscous losses due to surface friction and boundary

layer growth

� 2-Dimensional Axis-Symmetric analysis allows for fast solving time with refined mesh in

areas of shock development

Intake Restrictor

� Air flows from throttle to engine intake port through intake manifold

� Intake Plenum

� Acts as air reservoir for engine to draw air from during intake stroke

� Primary purpose is to damp out pressure pulses from intake stroke to create steady flow

Intake Manifold

� Primary purpose is to damp out pressure pulses from intake stroke to create steady flow

conditions at the restrictor

� Intake Runner

� Path through which engine pulls air from the plenum into the combustion chamber

during intake stroke

� Length decided by harmonic frequency at various engine operating speeds, can be used

to create a resonant “tuning point”

� Transient Pressure Boundary Condition used to simulate pressure pulses

within manifold from intake stroke

� Piecewise-Linear Approximation used for initial analysis trouble-shooting

� End analysis will use pressure trace measured during Dynamometer Testing

Intake Manifold

� Component Simulation

� Shroud structure analyzed to ensure uniform airflow distribution across radiator face and

verify proper mass airflow through radiator

� Radiator modeled as a material resistance with heat addition and flow re-direction to

properly simulate airflow through core

Cooling System Airflow

properly simulate airflow through core

� Full Car Simulation to verify shroud is receiving adequate airflow

� Simulation model still in progress, needs additional geometry and refinement

Cooling System Airflow