Formula sae restrictor design convergent and divergent part 1 D Simulation and Length Optimization

20mm is restricted dia for intake air as per FSAE ( formula student).

Vary convergent nozzle inlet diameter, length and outlet diameter; and then check its impact on engine torque.

First Throttle side - we found We can conclude from below graph that D4525020 has uniform torque compare to other pipes. Proposed Convergent Specification:

Inlet Dia = 45 mm same as Throttle Bore; Convergent Pipe Length = 250 mm; Outlet Dia = 20 mm (FSAE Regulation) 

Now Divergent part of Diffuser will be optimized to get high constant torque. We will vary only divergent pipe length and outlet diameter at Plenum.

Proposed divergent pipe specification:

Convergent Pipe Length = 250 mm

Outlet Dia = 60 mm (Intake Plenum Entry Dia); {Inlet Dia = 20 mm (FSAE Regulation) }

Stress Simulation:

On the basis of manufacturability in lab and available material. For same material (steel, thickness 1.2mm) a CAD data was made with length as per simulation result. Stress Simulation was done in Solid works for analysis of proposed design. It is clear from simulation result that steel with given thickness can be used for Restrictor Pipe. 

As explained in Intake Manifold Simulation; there are variations in Plenum Pressure which will leads to intake noise. To damp this noise a silencer design is proposed on the basis of simulation. Noise was not measured physically so torque data will be used to finalize silence selection; Noise Simulation was done in Lotus Software with proposed design because we verified noise by activating speaker in Lotus Software.    

Conclusion From Above Graph:- If SP ( simple perforated) type silencer is fitted in intake system them it will eliminate torque dip at low RPM near 4000 rpm to 8000rpm and reduce intake noise.