Modelling and simulation of flow through a flowbench
Aim:
- To create a 3D model of flow bench in SOLIDWORKS and run a CFD baseline flow analysis.
- To plot valve lift vs. mass flow rate and valve lift vs. pressure drop in the system.
Theory:
Flow bench:
An air flow bench is a device used for testing the internal aerodynamic qualities of an engine component and is related to the more familiar wind tunnel.
It is used primarily for testing the intake and exhaust ports of cylinder heads of internal combustion engines. It is also used to test the flow capabilities of any component such as air filters, carburettors, manifolds or any other part that is required to flow gas. A flow bench is one of the primary tools of high-performance engine builders, and porting cylinder heads would be strictly hit or miss without it.
Usually, in the flow bench we take the port which is to be tested, however in this project we are simulating the intake port.
Cylinder dimension:
Bore diameter: 0.05m
Length of the cylinder: 0.1m
Outer intake manifold diameter: 0.02m
Thickness: 0.002m
Boundary conditions:
Inlet total pressure 172369 pa at temperature 293.2k
Outer static pressure is taken as 101325 pa at temperature 293.2k
Grid dependency test:
Grid dependency test is also called as mesh dependence test, in which the model is subjected to successive smaller cell sizes for calculations, that is the model is divided into smaller number of parts called as elements and calculations are made. As the element size decreases the error towards the result reduces.
Procedure:
- First, the 3D model of the flow bench geometry in SOLIDWORKS and the necessary boundary conditions were set up in the flow simulation wizard.
- The boundary conditions were: setting the flow to internal, Inlet total pressure 172369 pa at temperature 293.2k, Outer static pressure is taken as 101325 pa at temperature 293.2k.
- Grid dependence test will be done on grid level 3,4 and 5.
- A parametric study was done for getting mass flow rate vs. valve lift from 1mm to 8 mm so, proper cut plots and goals were defined and parametric study was carried out.
- The input parameter was varying valve lift.
- After getting the results for grid level 3, 4 and 5 plots were obtained and studied.
Results:
Grid level 3:
Cut plot for valve lift 1mm:
Cut plot for valve lift 2mm:
Cut plot for valve lift 3mm:
Cut plot for valve lift 4mm:
Cut plot for valve lift 5mm:
Cut plot for valve lift 6mm:
Cut plot for valve lift 7mm:
Cut plot for valve lift 8mm:
Results:
Variation of pressure drop w.r.t to valve lift:
Variation of mass flow rate w.r.t to valve lift:
Grid level 4:
Cut plot for valve lift 1mm:
Cut plot for valve lift 2mm:
Cut plot for valve lift 3mm:
Cut plot for valve lift 4mm:
Cut plot for valve lift 5mm:
Cut plot for valve lift 6mm:
Cut plot for valve lift 7mm:
Cut plot for valve lift 8mm:
Results:
Variation of pressure drop w.r.t to valve lift:
Variation of mass flow rate w.r.t to valve lift:
Grid level 5:
Cut plot for valve lift 1mm:
Cut plot for valve lift 2mm:
Cut plot for valve lift 3mm:
Cut plot for valve lift 4mm:
Cut plot for valve lift 5mm:
Cut plot for valve lift 6mm:
Cut plot for valve lift 7mm:
Cut plot for valve lift 8mm:
Results:
Variation of pressure drop w.r.t to valve lift:
Variation of mass flow rate w.r.t to valve lift:
Conclusion:
- As the grid level is increased the values become more precise.
- With increase in valve lift, mass flow rate increases.
- Generally, with increase in valve lift, pressure drop decreases but some abnormalities can be observed.