12 Discretization process in gt power

1.Tutorial- single cyl DI add case 2 with discretization length 0.1 mm for intake runner and compare with default case

• Parameters-Torque, BSFC, max cylinder pressure
• simulation time

Explanation

A 1cylinder diesel engine model is used to study the discretization length

the above discretization length values used for rhe intake runner case1,the discretization length is 40mm and for case2 the discretization length is 0.1mm

Engine performance parameters

engine torque comparison

Case1

Case2

Engine BSFC Comparison

Case1

Case2

Engine peak pressure comparison

Case 1

Case2

Simulation time comparison

When you increase the discretization length more number of sub volumes are present in your flow domain.hence you capture the change in the folw properties verywell which calculate the performance parameters accurately.

when you have more flow volume you calculate the pressure losses accuratly which results in the decrease in volumetric efficency

2. Explore tutorial no 2 (GEM3D) - “Building intake manifold from STL model” (80 marks)

ANS:-

the discretization is aprocess of dividing the CAD geometry in to differnnt flow regions and converting them in to a 1d gtmodel components

CAD GeOMETRY

the above CAD model is the intake manifold of engien

Step1 dividing the geometry in to diffrent flow volumes

the above cutting plane option are used to divide the given CAD model int o differnt flow domains. the below image shows A 3 point cutting plane

The cutting plane can be rottated and translated to palne it at the the required position and direction

The above image shows a CAD geometry divded in to different flow regions

Step2 Converting the flow domain in to gt-components

Step1

We have to select which type of component is flow volume and port no 1 is inlet and outlet

Step2

it takes the geommetry details of the flow volume

Step3

this step takes the values of various physical parameters realated to flow componemts.

Step3 Adding connections to the flow components

Flow connections like orifice and assembly extension can be added for the flow components as show below

A Shadow ca be see in the above image which is an orifce between two pipes to include flow losses due to change in the cross section of flow volume

Similarly a gap between any flow componets can be filled as shown in the below image

After copleting all the steps the discrtized CAD model has to be exported in gtmodel as shown below