[MVRC] Mantium Virtual Racecar Challenge 2016

[TalnoRacing]

So my new car was a big disappointment . Other than a big improvement in engine cooling, there was NO balance which means no front downforce (the front wheels probably lifted off the ground ). One positive is that the new design has very low drag, so there is room for improvement.

[etsmc]

Egar to see the full results for my car because my exhaust placement was a technical loophole in the rules and still did not provide the benefit I was after.
My exhaust was placed ahead of my cooling intake to try and take advantage of the air coming out of the exhaust into the radiator to bring my numbers up for the intake. but all it gained was a 2% increase in power.
Could the issue be that the flow out of the cooling is restricting the flow through the heat exchanges? this is something I will look into.

Also interesting to see most people are struggling with balance, I find this most interesting because I know my diffuser is really basic and have not really looked into optimizing it yet. No matter what I have tried I can not get the CoP lower than 2.0 and I have tried wings, front diffusers and a mixture of the both.

With such a short amount of time between this round and the next, I will have to try and come up with something. Oh and no doubt move my exhaust

[CAEdevice]

Hi etsmc, the exhausts would be a bit to hot in order to have a realistic cooling. Why don't you try to put the engine intake into the cooling ducts, just behind the radiators?

I am joking: I think that the engine intake flow (and exhausts) is an average value and it is not enough to give advantages anywhere.

[etsmc]

Hi etsmc, the exhausts would be a bit to hot in order to have a realistic cooling. Why don't you try to put the engine intake into the cooling ducts, just behind the radiators?

=D>

[LVDH]

Funny guys, unfortunately I just read the draft of the new rules. Chris is ahead of you.

Tomorrow I will visit the OpenFOAM conference and try to find us some sponsors so I will spend some time polishing the Challenge page today. I already have cool renders from you guys that have still not been published but if you have more please upload them to the Dropbox link from last race.
With some luck I can get us an HPC provider.

[CAEdevice]

Good news, thanks for the update.

I have a question about the cooling rules.

Wich surface (inlet/outlet) is used to measure the cooling flow (the values are a bit different sometimes)? I have chosen safe settings for the first two races (3.1-3.2 m^3/s), but the competition is getting harder and I have to refine the car.

[CAEdevice]

It's interesting how all but Matteo are struggling with engine power.

I invested three weeks before the first race only studing the best cooling configuration (the car that I used in the first two races is 95% identical if compared with the car I used for the last KVRC race).

What I would suggest is to focus more on the "energy" (pressure and velocity) that goes through the cooling inlets than on any other thing (surfaces area, heat exchanger dimensions, cooling outlets, ...).

It is the same concept of the Deadman's curve for helicopters, but with "pressure" instead of "altitude".

[LVDH]

Good news, thanks for the update.

I have a question about the cooling rules.

Which surface (inlet/outlet) is used to measure the cooling flow (the values are a bit different sometimes)? I have chosen safe settings for the first two races (3.1-3.2 m^3/s), but the competition is getting harder and I have to refine the car.

OK, I have received many questions about this now. For one guy I made a good screenshot explaining it very well. If he allows I will write a small blog article about this using the image. If not you will have to wait a few days until I can replicate it on the MantiumRacer. Mainly the problem is that some of your measurement surfaces are triangulated very poorly causing interpolation issues which make the measurement unreliable. I create my own surfaces on the cars with 10mm triangles. This then works very well. There was some talk about this a few weeks ago on this forum.

[CAEdevice]

Good news, thanks for the update.

I have a question about the cooling rules.

Which surface (inlet/outlet) is used to measure the cooling flow (the values are a bit different sometimes)? I have chosen safe settings for the first two races (3.1-3.2 m^3/s), but the competition is getting harder and I have to refine the car.

OK, I have received many questions about this now. For one guy I made a good screenshot explaining it very well. If he allows I will write a small blog article about this using the image. If not you will have to wait a few days until I can replicate it on the MantiumRacer. Mainly the problem is that some of your measurement surfaces are triangulated very poorly causing interpolation issues which make the measurement unreliable. I create my own surfaces on the cars with 10mm triangles. This then works very well. There was some talk about this a few weeks ago on this forum.

I am not sure about that: I am using triangles with maximum dimension 8mm and max width/height ratio 2, but I still have a difference between inlet and outlet (0.1-0.15 m3/s). What about using only one measurement surface in the midde of the heat exchanger? It would make things easier also in case of multiple cooling ducts exits (in real cars, cooling ducts exits are not even defined somtimes)

[LVDH]

I am not sure about that: I am using triangles with maximum dimension 8mm and max width/height ratio 2, but I still have a difference between inlet and outlet (0.1-0.15 m3/s). What about using only one measurement surface in the midde of the heat exchanger? It would make things easier also in case of multiple cooling ducts exits (in real cars, cooling ducts exits are not even defined somtimes)

Well it is CFD, the numbers never perfectly add up. If you look at flow visualizations you will see recirculation zones in front of the radiator on most cars. This also makes it hard to measure the exact flow on the cooling inlet surface. On the rear one everything is much better straightened out thanks to the radiator. And as the radiator straightens the flow so well and we are getting rid of the other two surfaces there will be a new surface which is actually located in the center of the radiator. This is actually how I measured the flow on you cars for the races.

[CAEdevice]

I am not sure about that: I am using triangles with maximum dimension 8mm and max width/height ratio 2, but I still have a difference between inlet and outlet (0.1-0.15 m3/s). What about using only one measurement surface in the midde of the heat exchanger? It would make things easier also in case of multiple cooling ducts exits (in real cars, cooling ducts exits are not even defined somtimes)

Well it is CFD, the numbers never perfectly add up. If you look at flow visualizations you will see recirculation zones in front of the radiator on most cars. This also makes it hard to measure the exact flow on the cooling inlet surface. On the rear one everything is much better straightened out thanks to the radiator. And as the radiator straightens the flow so well and we are getting rid of the other two surfaces there will be a new surface which is actually located in the center of the radiator. This is actually how I measured the flow on you cars for the races.

Ok, measuring on the rear outlets looks a good idea

[LVDH]

center of the radiator

[Alonso Fan]

center of the radiator

So what is the exact reason for loss of engine power? I made the suspension covers less obstructive and still my power is the same

[LVDH]

I am a bit sick so I am slow today. You will hopefully receive the flow visualizations today. But while your car looks very good, somehow no parts work properly, although you have improved them all. You also have a slightly improved cooling flow but not enough for it show with the engine power not having decimal places in my table.
One good thing though is that although you scored last position in both races you are not last in the championship! So keep those improvements coming.

My suggestion is to google for radiator duct design or do what RicME did last season and ask the forum to help him. It did wonders to his car.

[CAEdevice]

You could release your car as OS (you have not very much too lose at this point).