Simscape Isothermal Fluids - Pressure sensor

This is a system of a gear pump connected to a load. The angular velocity is to be maintained constant. The Pressure sensor reads only 1.12bar, it does not reflect the pressure due to the conneted load. Am I missing something here?. There is a load of about 300kgs which needs to rotated, so there should be pressure built up due to the load.

[Vinay]

Hii Gokul, Can you share the simulink model file to better understand the parameters of the blocks and the problem.

[Gokul]

The signal coming from sensors are for output display, so taking these value and adding a load to it will not affect the pressures for load changes.

Answer 1

[Shivam Gothi]

Hello @Gokul,

Let us address your questions one by one.

1) Am I missing something ?...

I referred to the Simulink model attached by you in the comment section and found that the “torque sensor” was not placed appropriately.

The torque sensor must be placed in “series” with the driving shaft. In this case, it must be placed between “C” port of “Rotational Spring” and “Inertia” block as shown in the below figure.

2) Increasing the load torque on mechanical drive shaft.

Here, an additional “rotational damper” is placed in order to simulate increase/decrease of load torque.

In order to increase the load torque on the mechanical drive side, increase the value of friction coefficient “B” of the “rotational damper” block and in order to decrease the load torque, decrease the value of “B”.

The below given simulation results are corresponding to the value of B = 0.05.

Conclusions (at steady state):

• Pressure sensor reading: 1.458e+05
• Rotational speed at “O” port of “gear box”: 103.8
• Rotational speed at “S” port of “gear box”: 51.9

In order to simulate increased load torque, I made “B” = 0.1 and got the following results:

Conclusions (at steady state):

• Pressure sensor reading: 2.911e+05
• Rotational speed at “O” port of “gear box”: 51.89
• Rotational speed at “S” port of “gear box”: 103.8

Conclusions about the simulation:

As we increase the load torque on the mechanical drive side, we can see that the pressure of the “isothermal fluid” has now become equal to “2.911e+05” as compared to its previous value of “1.458e+05”. Also, the speed at “O” port “gear box” is non-zero

I am also attaching the reference Simulink model with this answer.

I hope this helps !

[Gokul]

Yes, thanks for the reply.

[Gokul]

I am about add a ramp signal, unable to connect to simscape, donot have driveline for a variable rotational damper.

Any suggestion.

[Shivam Gothi]

hello @Gokul,

Please clear my doubt:

where do you want to connect the ramp ? That is, where are you trying to give the ramp input ? I am not able to understand the term: "variable rotational damper"

[Gokul]

Hi

I want to model a load which increases linearly so that because of the load there is a change in the pressure line. This load is due to the damping of the system. I do not have a 'driveline' module to use the variable rotatonal damper which creates a ramp signal.

I am trying to connect the ramp signal to the damper.