Oil Inlet Plenum

And we’ll talk about the last main plenum that we want to add in, and that’s going to be the oil or sorry, the fuel inlet. So I’ll turn on the bottom plenum here, let me give it some color.

As it stands right now, if we were to print this lattice structure, we would have a pretty significant overhang and maybe even need some extra supports at the bottom of this TPMS structure. We’re going to go forward with the same plenum design that we used in previous examples. And what that ultimately is going to be is some form of torus or ellipse cutout that is revolved around the axes to make it self-supporting.

And again, I’m going to want to tie the generation of this plenum to various aspects within the CAD, so that if one updates, the plenum updates, or if I want to change a parameter in the implicit workflow, everything updates accordingly. Come up to the CAD and fluid bodies, and isolate the CAD body of the infill. And under the CAD and implicit references, we’re going to add to this. So I’m going to capture the bottom edge of this implicit, of this CAD edge. And in this case, it says Create Section Variables. This is because I’ve selected both edge and a face. So if I select this, it’s going to give me two different entities in the notebook: the CAD edges that I selected and the face. So in this case, I don’t need the face, I’m just going to delete it.

In other words, if I had spent, you know, a little bit of time going through and selecting all these edges and I accidentally click a face, it’s not a big deal if you accidentally select it and didn’t mean to. We’re going to rename this variable OD edge infill. Minimize that. And we’re going to get the center of this. So I’m going to search for Center Point, and in this case of CAD cylinder or hole, the input it’s just going to be a CAD edge list, which we’ve just captured, and I’m going to make this a variable. Now in this case, we also could have used the Cardinal Face Points block as well, but this is a nice one to have in your toolkit. We’ll rename this infill B point.

We’re going to create a new section under sidewall plenum extension. Add section. And we’re going to call this fuel inlet plenum. We’ll call on the Ellipse From Remap block that will go into our fuel inlet plenum and we’ll set the initial operand to one, so that our initial radius equates to a sphere here. We’ll buff this up to 10. We can turn our infill back on and look at a cross-section. Now we’re going to want the ellipsoid in this case to be driven from the center point that we created at the bottom. So we’ll come into the center point of this Ellipse From Remap to define a new point. The Y and Z C are going to be constant at the center point value for the infill and we’ll vary the X value so we have control over its distance from that point. We’ll make this operand a variable, and I’ll call it ellipse location, and I’ll just set it at 12 millimeters for now.

So looking at the ellipsoid, we can right away see that at the current radius that it’s at, we are going to exceed the overhang constraint. So ultimately, we’re going to need to squish it in the X axis. So we’ll come to this X operand and start to play around with this value. We’ll call the Angle Field block once more and I’ll hold the control key and drag and drop the Ellipse From Remap in here. Hit F on the angle field and change the plane from normal, and then we’ll turn off the infill. We’ll set up our custom range once more from 0 to 45, adjust our intervals and change the color map to turbo.

So in this case, when we probe our values and find our 245 degree planes, we can see that in this case we’ve actually hit on that value pretty closely, that 3 mm overhang. So what we’re going to end up doing with this ellipse is do a revolved cut around the infill axis to make a plenum. We’ll close the field viewer. And we’re going to take this Ellipse From Remap and we’re going to revolve it. So we’ll select the Revolve Profile. We’re going to want a section body and we’ll go ahead and section this Ellipse From Remap. Now, as we are nesting this block in, we’re going to want to access the different variables. So we can right click and pull these operand out. So we’ll call this ellipse radius and then we can call this remap value for.

Now we’re going to want to section the plane that we want to cut at. So we’ll select Plane From Normal. We can just type it in, and the origin of this plane is going to be the point that we created—this point three. And the cutting plane we’re going to want to put in the XZ plane. So our plane, so our vector here, is going to go from 0 1 0. We can isolate this section body and just double-check that this is what we’re going to revolve.

The next input for the revolved profile is an axis. We’ll come under our CAD implicit references, and I’m going to call on the Compound Block Axis Through CAD Cylinder or Hole. All it needs is a list of CAD edges and a CAD face. We’ll delete the list input because we already have that up here. So this will be the OD bot edge of our infill. And we can open up the properties and look at the information and see that we need a CAD face that is normal to the hole or cylinder that we want to put an axis through. So we’ll turn on the infill. Capture this face CAD face variable. We can call this infill bot face. Drag this into here. Move the CB below it. And all we’ve done is created an axis that moves through this cylinder. And I’ll call this infill, I’ll call this Axis Through Infill. So we’ll use this now as our axis for revolution and do it at 360 degrees. Turn that revolved object on. We have that. I’ll make this a variable and I’ll call this inlet plenum segment one.

The next step is going to be intersecting it with the infill volume because we only need the top half of this revolved profile. So I’ll call the Intersect block. I have modeling open, so I’ll just click the Boolean Intersect. Drag this segment one in and search for the infill implicit. We’ll make this a variable and I’ll call this inlet plenum main segment. Isolate that just to double-check that we have created what we want.

The final step before we get to adjusting the parameters and making this whole lattice structure self-supporting is to Union this main segment to the bottom plenum. So we’ll drag the inlet plenum into here and we’ll just type and call the bottom plenum. Make this a variable, isolate it, and we can call this updated bottom plenum. Minimize these blocks and make the angle field of variables. Since we’re here, we’ll call it fuel plenum angle eval.

Turn the infield volume back on. Look at a quick cross-section again. And we know that we’re going to want to update our design space. We’re going to want to remove this material. So we’ll come under our Hex Core and Fluid Generation. Open our design space and click this plus sign. We’ll drag the updated bottom plenum into here and everything will update and recalculate. We can turn this off. Look at our hex core. Maybe turn our shell on as well as one of our fluids. Let’s turn our final hot fluid on. And real quick, we can see that we’ve skipped a step earlier on, and it was more or less on purpose just so we can add it in. And it’s a pretty minor one, but the infill volume gets trimmed off by the outer shell. So we’ll go ahead and add that on. We’ll add an Item To List. We’ll put the shell here. So we’re just going to remove that little bit, the fillet there at the bottom.

While that’s calculating, I’ll turn off the infill and see that we’ve updated not only the lattice structure but the fluid domain as well. Next couple steps are to update the baffles as well as this final cold fluid because right now we’re not going to have this added plenum region in. So we’ll come to the baffles first. This is going to be the cold inlet baffle volume. This is going to become the updated plenum. So we’ll remove this. Search for updated plenum and then do the same thing in this raw final cold fluid. Remove the bottom plenum. Say update and go from there. So now we’ve updated the baffles, our final fluid volumes, the hex core, as well as the final part that we’re ultimately going to print. Now that this is all tied together, we can close these sections and we’ll look at updating the position of our cutout or this bottom plenum to be self-supporting during the print process.

Turn the shell back on just so we have some form of visual reference as well as the oil outlet pipe. And I’ll give these some random color to better visualize where we’re at. So ultimately, the location that this plenum is at isn’t going to work. Let’s increase this ellipsoid location a little bit. Maybe we go to 18 mm. That puts it pretty close at the center. But again, we’re going to have a pretty large overhang on either side of this section. So there are a couple ways that we could tackle this. We could increase the ellipsoid’s radius. So let’s bump this up to 15. Decrease the remap value. So we’re going to unsquish it a little bit. And indeed, we’re removing some of that overhang, but we’re removing it at a cost of surface area. Right? We’re increasing the amount of design space we’re removing. So we want to try and find a balance between both the flow distribution into the hex core, self-supporting nature of the structure, and ease of design iterations. We can do a quick evaluation, let’s say, of the surface area of our hex core. So we’ll do a search for surface area from body. We’ll drop our Hex Core into here and remember, the surface area that’s going to be outputted is going to be both the hot and cold side. So if we’re just wanting to focus on one, then we would do our context search divide by two and get half of that area approximately. So we could compare this to what our hand calculations might tell us we need.

So we come back to our ellipsoid location. We have everything else set. Maybe we need to adjust these parameters to increase our wetted surface area. I’ll bring the ellipsoid radius back down to 10 and we’ll leave the remap value at two.

Now, one thing I want to point out quickly, and this is the next aspect that we want to tackle regarding this ellipsoid, is let me turn the hot fluid on. So as it stands right now, all of the oil that would otherwise come down through this Hex Core is now going to get trapped between the shell and this plenum we’re creating. There are a couple ways that we can go about resolving this. We could say that any of this region in the hot fluid domain, let’s just turn to solid. So this will become solid material. That’s not ideal. We’re adding weight and we’re adding a pretty big chunk of material in an otherwise thin structure. So we could that could lead to some extra thermal stresses as the part is being built.

Another possible design option is to create a funnel. And we’ll go ahead and do this in a bit that lets all of this fluid just filter down and around and exit out the bottom. But at that same time, we’re now going to have, let’s say, a bunch of trapped powder or wasted empty space and region in here. So ultimately what we might want to do is we’ll shift the ellipsoid in this case over a bit. So let’s bump this out to 24, let’s say, right up near the edge. Maybe we can have a little bit of overhang. So let’s look at our quick ruler, find where we have about 3 mm, and adjust this value. So we can go a little bit further, maybe to 22. So roughly now we’re going to have about a 3 mm or less overhang between the shell and this plenum.

And the reason that I wanted to make a note of that is we’re now going to have a pretty large overhang here at the bottom. The way I envision resolving this is just adding a bit of extra support structure that’s going to revolve around. And rather than this being a bit of solid material, we’re going to now add to our design space. So we’re going to add this triangular bit. It’s going to be tied to the location of the edge of the ellipse here, and we can ensure that this angle is always going to be 45 degrees regardless, or whatever we want, regardless of where the ellipsoid moves, how tall it becomes, etcetera.

So for this next section, for both this revolved support cut, as well as the funnel, we can call it that, will create above the ellipsoid here. I won’t walk through all of the steps that I take to do it. I’ll just fast forward the video and then talk to the major points once that’s all completed.