Modelling and simulation of flow through a flowbench
Modeling and simulation of flow through a flow bench
Aim: model and simulate flow bench simulation plot valve lift vs mass flow simulation parametric study
introduction:
computational fluid dynamics (CFD) is a branch of fluid dynamics that uses numerical analysis and data structure and solve problems that involve fluid flows.
internal flow is any flow of fluid through the circular or non-circular body structure flow channel where the confining wall guide the flow from an arbitrarily defined inlet state to an outlet state.
valve lift: a valve in the cylinder head of an internal-combustion engine that opens at the proper moment in the cycle to cycle to allow the fuel-air mixture to be drawn into the cylinder.
mass flow rate: rate of movement of liquid pass through a unit area. mass flow rate directly depends on the properties of fluid and area of cross-section.
case setup
modeling
cylinder
valve
inlet port
flow simulation setup
project name:valve_lift_study
parametric study : grid dependence test
flow: internal flow
fluid: air
velocity 100m/s (x-axis)
boundry condition
at inlet (lid1) : total pressure
at outlet(lid2) : static pressure
goal
global goal : mass flow rate
surafce goal (at outlet lid2 ): mass flow rate
mesh setting for grid dependace test
global mesh setting : automatic
initial mesh seeting :3
valve lift :2mm
grid dependence test result
| Goal (Value) | Design Point 1 | Design Point 2 | Design Point 3 |
| Level of initial mesh (Automatic Mesh) [ ] | 3 | 4 | 5 |
| GG Mass Flow Rate 1 [kg/s] | 1.15995E-09 | -6.7179E-09 | 1.29992694265241E-08 |
| SG Mass Flow Rate 1 [kg/s] | 2.99084E-05 | 1.95107E-05 | 8.25078E-06 |
plot result
grade dependence test conclusion
as the mesh size increases the calculating grid area size reduces to improve calculation accuracy
to decide grid meshing level in global goal mass flow rate plot and surface goal mass flow rate shows above
by comparing design point 1 2 & 3 design point 3 shows good result and accuracy to result so considering automatics mesh level 5
new parametric study for valve lift study
input parameters
selecting the dimension parameter (distance between cylinder and valve face)
discrete value of valve lift dimension
| Goal (Value) | Design Point 1 | Design Point 2 | Design Point 3 | Design Point 4 | Design Point 5 | Design Point 6 |
| D1@[email protected] [m] | 0.001 | 0.0013 | 0.0016 | 0.0019 | 0.0022 | 0.0025 |
output parameter
global goal mass flow rate
surface goal mass flow rate
Result of valve lift parametric study
| Goal (Value) | Design Point 1 | Design Point 2 | Design Point 3 | Design Point 4 | Design Point 5 | Design Point 6 |
| D1@[email protected] [m] | 0.001 | 0.0013 | 0.0016 | 0.0019 | 0.0022 | 0.0025 |
| GG Mass Flow Rate 1 [kg/s] | 1.08528E-07 | -3.16217E-08 | -4.80984E-08 | -1.64677E-08 | -2.9567E-08 | 2.43675E-08 |
| SG Mass Flow Rate 1 [kg/s] | 1.02366E-07 | 1.30791E-05 | 6.04481E-06 | 4.32165E-06 | 3.60263E-05 | 1.61878E-05 |
global mass flow rate plot
surface goal mass flow rate plot
cut plot
observation and conclusion on valve lift vs mass flow rate:
1)global goal mass flow rate
as valve facelift, the mass flow rate increases at a certain distance afterward the mass flow rate lowers and fluctuate
2) surface goal mass flow rate
as valve facelift, the mass flow rate increases