Modelling and simulation of flow through a flowbench

Aim :

1)To perform CFD analysis of flow though flow bench.

2)To Perform grid dependancy test.

3)To study effect of valve lift on mass flow rate.

4)To obtain a plot of lift Vs mass flow rate.

Introduction :

what is flow bench ?

Air flow bench is basically a device used for testing internal aerodynamics qualities of an engine. It is used for testing intake and exhaust ports of cylinder heads of internal combustion engine.It is also used to test flow capablities of components such as air filter,manifolds,carburator etc.It is one of the primary tool in high performance engine builders.

Construction and Working:

It consist of air pump,pressure and temperature measuring instruments,metering element.test piece is attached in series with pumps and measuring elements and air is pumped through it.therefore volume flow rate of flow trough test element can be calculated from flowrate of flow throgh metering element and mass flow rate can be calculated by knowing the temperature and pressure data.

In this project we are simulating this flow bench experiment in solidworks.

case setup:

geometry :

3d modelling is done as per dimensions shown below.

After modeling computational domain and boundary conditions are defined.local refinement of mesh along valve face is done.boundary condtions are desided as follows-

since we are simulating intake stroke and assuming that their is no supercharging so,air will come in combustion chamber solely due to vacuum genrated by piston.hence apply static pressure of 101325 pa at inlet lid indicating it is connected to atmosphere. and 30000 pa indicating suction pressure at outlet lid.temperature is taken as 293.2K.

1)Grid dependancy test

we will check mass flow rate for valve lift of 5mm for mesh refinement of level 3,4,5.

pressure contours -

Velocity contours-

Variation of goal convergence with mesh refinements -

Variation of mass flow rate with mesh refinements -

from above results it can be concluded that as mesh refinement increased,goal convergence is improved.so for furthur calculation mesh level 5 is selected based on grid dependance test.

2)Effect valve lift on mass flow rate

Consider valve lift varies from 0.1 mm to 10 mm

pressure contours -

Velocity contours -

3)Plot of valve lift Vs Mass flow rate

swirl animation-

Conclusion -

from above results it can be concluded that as valve lift increses mass flow rate increases and reach to saturation point above which mass flow rate remains constant.

reference-

https://en.wikipedia.org/wiki/Air_flow_bench