Centrifugal Pump Design with Ansys TurboSystem - Part 3

In the third part of our video, we're going to focus on the CFD modeling and execution. So for this purpose, we are going to transfer the data to CFX, and we're going to use CFX-PRE to set up our model, but we also need to connect our volute mesh as an input to CFX.

As you can see, the mesh right now needs to be updated, so we do a right-click, hit "update." Again, going to quickly execute the mesh. Once it turns to a green checkmark, we can then go ahead and double-click on the setup, turn up button, and call CFX. All right.

So this is going to pop up the CFX-PRE window. As you know, this is essentially the software to set up the case, and what we see is two separate volumes for the volute and CFX-PRE.

So we have a 1-8 sector of our blade, and when I look at this, one thing that looks concerning is there's this overlap region between the two domains. And typically, this is a problem in CFD, but not in this particular case, and I'm going to explain that why during the setup phase.

So let's go ahead and start with the setup. For this, let's go to tools. We're going to go into turbo mode, which is going to make our life very easy in terms of setting up the configuration.

Our machine type is a pump, and we're going to be rotating about the Z-axis, and we're solving a steady state problem. So I'm going to hit next, and let's start defining components. So R1, when I click on it, picks up bolt of torque. All right. So I'm going to pick up the bolt once.

But what I want to do is click on here, available volumes, and I want to pick the passage. And also, it's rotating at 2,000 RPM. I apologize, 1,600 RPM. All right. Let's go ahead and start. Okay. So I'm going to pick up here. And let's put a minus up front to correct the rotation direction.

And we also want to add another component. So we go to components, right-click, add component. And we're going to do a stationary component, which is our volume. So we go to our available volumes. We're going to pick B75, which is higher. Okay.

So we're going to pick B 75. We're going to add a component. We're going to hit next. Highlight it. And then we can hit next. It is time to define our working fluid and some boundary conditions. So we're going to use water as our working fluid.

It's always good to do the P total inlet and mass flow at the outlet. So we're going to do per machine. And it's going to be 1,500 RPM. And it's going to be 0,000 RPM. And it's going to be 1,000 RPM. Okay. 300 cubic meters per hour which translates to about 83.33 kilograms per second.

And we're going to hit next. And here for interfaces, we're seeing this message and you know it gives a warning because there's a mismatch. Here you can see there's an overlap between the two domains. But you know we're going to say hey just go ahead and create interfaces anyway.

And then we'll of course go ahead and check these interfaces later on. So let's hit yes here and keep moving on. So next step is we can enter general mode. This wraps up our setup. And let's hit yes to the warning. And it seems like actually we do not have an error.

We just have some warnings and what we want to do is check the interfaces. So let's look at, so this is our inlet block, our periodics which makes sense. And then the critical one is this connection. This is the input. It's between the rotating and the stationary components.

And it seems like it created a correct interface between the two blocks. Next, let's take a look at our solver control. Let's put 500 iterations. Let's stick to the auto time scale control with three orders of magnitude reduction. Let's hit apply. And close. This actually concludes the setup phase.

So what we can do is go ahead and start to execute the case. So I'm going to shake this window and go to our menu. Click solution which is going to bring up the CFX solver manager. So this will be a new window that pops up. And here what I want to do is I want to use double precision.

I'm going to run on my machine. I'll ask for just four processors. And I'm going to hit start run and see how our run goes. And looks like that there's a problem. So what we want to do is go ahead and check what the problem is. And seems like the window crashed.

So the output file indicated there was some memory allocation error. And it suggested to go. Go. And insert an expert parameter called topology estimator factor ZIF. And this happens from time to time. And what you can do is go under expert parameters, convergence control.

Turn on topology estimate factor ZIF. Which is by default one. And you want to make it 1.2 typically. So let's make the change. Hit apply. Hit OK. Shrink our window. And then we're going, we want to edit our solution. Bring the solver window again. Now that we made the change.

Let's start the run again. So this was the error previously. That was before. That was mentioned. I was talking about. So it's clearly indicating what the fix is in the CFX solver manager. And I was able to go ahead and make the change. So now the run is underway.

As you can see, it's putting in iterations. And it's going to run until convergence or up to 500 iterations. And then in the last part, section of our video, we're going to talk about the results. Thank you.