Gear Pump Design

Some time ago, one of our cus­tomers visited us in Potsdam. We were talking about our joint efforts to optimize various auto­mo­tive com­po­nents, when he came up with the wish of opti­miz­ing their gear pump designs. Well, frankly, our exper­tise with gear pumps is quite limited and we were not sure whether CAESES® can do the job of design­ing gears. However, we had a strong gut feeling that we have every­thing in place for it. We just needed to create a func­tional geometry model, while the customer could then add his exper­tise in sim­u­lat­ing these products. Since the shape is ​“only” a geo­met­ri­cal def­i­n­i­tion, includ­ing a good portion of inter­est­ing maths, we wanted to check it out. 

The Para­met­ric Model

One of our engi­neers had spent a couple of days to find out how to create a spur gear pump. So he started off with inlet and outlet design as well as the fun­da­men­tal curves of the device. There are some math­e­mat­i­cal formula to set up the size of these circles (more detailed: the root, base and pitch curves).

The tooth itself was con­structed by means of an involute. Basi­cally, you connect the ends of the straight lines that are tan­gen­tial to one specific circle. The length of such a straight element is cal­cu­lated by another math­e­mat­i­cal expres­sion. This is an iter­a­tive process, which can be wrapped into a feature def­i­n­i­tion of CAESES®. Feature def­i­n­i­tions are wrapped command sequences, similar to a small program or script. You can create them inter­ac­tively, or manually by typing in your sequence, includ­ing loops, if-state­ments and so on. In our case we needed to write to a command sequence that incre­ments the rota­tional angle by a certain delta, gen­er­at­ing the straight lines that get con­nected after fin­ish­ing the loop. The selected curve (colored yellow in the fol­low­ing picture) shows the result of the involute process:

Finally, the outcome of the ani­ma­tion creator in CAESES® is given in the fol­low­ing pictures where a second gear is also given: 

We con­ducted several sim­u­la­tions for the model where we sys­tem­at­i­cally changed all the gear pump para­me­ters. The result of one run is shown in the next ani­ma­tion. We checked the geometry and the cor­re­spond­ing flow behavior by creating a set of design can­di­dates auto­mat­i­cally with the design engines in CAESES®. The geometry creation process was com­pletely robust and all sim­u­la­tions suc­ceeded without any problems. So basi­cally, our col­league had finished a setup that can be readily used now for design studies and shape opti­miza­tions of this appli­ca­tion. Our customer is happy at this stage. 

Next Steps

This first model was an inter­est­ing start for us to get into the opti­miza­tion of these products. CAESES® really comes with the required method set to design these amazing products. The pre­sented work is still in progress, but our col­league imme­di­ately started to explore dif­fer­ent types of gear pumps. The last ani­ma­tion of this post shows parts of an internal gear pump, again modeled in CAESES® where the entire maths are wrapped in a feature definition. 

More Infor­ma­tion

We hope you have enjoyed this short blog post. Feel free to get in touch with us if you are inter­ested in gear pump design and opti­miza­tion. We are eager to explore things a bit more together with you!