Turbo Help!!

[Denisk31]

Hey Everyone,

I was hoping someone would be able to give me a bit of advice.

I am writing my thesis on the optimised design and manufacture of the restrictor unit, and the intake and exhaust systems for the application of a turbo charger to our formula student racing car.

I have got sponsorship from Garrett for the coming year. We are running a Honda CBR 600 Engine.

The question is as follows:

What books/papers/journals would you advise using to help with the analytical calculations for the application of a turbocharger i.e. I would like to be able to calculate the size of turbo which is required and then match it to either the GT12 or GT15v data to prove that it would be in their operating ranges? I am struggling to identify where I should start i.e. pressures across restrictor, therefore some books etc may help with this.

I would be greatful if someone could help,

Thanks in advance,

Denis

[Denisk31]

Hey Everyone,

I was hoping someone would be able to give me a bit of advice.

I am writing my thesis on the optimised design and manufacture of the restrictor unit, and the intake and exhaust systems for the application of a turbo charger to our formula student racing car.

I have got sponsorship from Garrett for the coming year. We are running a Honda CBR 600 Engine.

The question is as follows:

What books/papers/journals would you advise using to help with the analytical calculations for the application of a turbocharger i.e. I would like to be able to calculate the size of turbo which is required and then match it to either the GT12 or GT15v data to prove that it would be in their operating ranges? I am struggling to identify where I should start i.e. pressures across restrictor, therefore some books etc may help with this.

I would be greatful if someone could help,

Thanks in advance,

Denis

[JR @ CFS]

Hey Denis,

I always find a great tool on this website is the "search" function. There was a lot of talk around this time last year on turbos, with a lot of good input from experienced teams (i.e. who have been using a turbo successfully for a number of years)

Are Garrett simply sponsoring you with parts, or do you actually have access to Engineers at the firm as well? There will be people at the company who are "guru's," experts in the subject. Anyone really who has some knowledge. Don't be afraid to keep pushing them because if you don't ask you won't get! Just try all avenues like that before searching the SAE or Compendex data base, which can be costly when you wish to purchase a paper.

Also, start with your University library, they should have some books like the Engines bible (I can't remember the name of it, but it is thick and yellowy orange). Hope that is of some use to you!

[Nima]

when I was new in this forum the others said me to search befor ask any questions. there is a lot of informations about any fsae subjects. I think the questions that are asking here must be only in the new events and the basic designing discussions are extra posts.

[Denisk31]

Thanks for the advice guys. I found the post with all the referenced books.

I'm still struggling with the calculations even though I found posts regarding the subject.

I have calculated the max volumetric flow rate for choked flow through the restrictor. One of the posts says that you must then "assume a reasonable volumetric efficiency for the engine at different RPM levels and figure out the volume flow it wants". What is a reasonable volumetric efficiency for the engine and how do I calculate the volume flow it wants. The volume of the engine is 599cc but I don't know how to calculate the density of the air/fuel mixture to get the mass flow rate. Following this the same post says "compare the two values of flowrates for a range of RPM" but I am unsure why and where I can take it from there.

Excuse my ignorance if this is really simple but I am really keen on getting this on the car for next year and again, thanks for your help guys

Denis

[bigwig]

http://www.not2fast.com/turbo/glossary/turbo_calc.shtml

You can use that calc for rough calculations. VE estimates will depend on where you want your power. R6 engines have roughly 100% VE in the 8-12k powerband so if you decided to compliment that part of the powerband, then the VE would be over 100% at that point. Most likely be in the 120-140% range assuming you build a relatively standard turbo setup. You also have to note that if you figure the engine is running at 120-130% VE at 10krpm, its going to require quite a bit of air flow from the turbo. Now using a small turbo like the GT15 you will notice compressor efficiency will start to decrease dramatically. By 12krpm you may have a lower VE than you would have had NA because of the increased intake air temps and exhaust reversion. So basically chose where you want the powerband to be, and make sure you have a turbo that will provide the power there, meaning it will be able to flow the necessary amount of air. The other turbo components should simply focus on complimenting the turbo choice thus increasing where you want your power. Turbos on autocross cars are very difficult simply because of the idea of getting great throttle response with a broad powerband can be a difficult challenge. Look at 80's F1 cars to get some ideas.

[pengulns2001]

i would assume for a thesis you would need to go way more in depth than a basic calculation to determine turbocharger sizing. determining what turbo to use and why including calculations wouldnt take up more than 3-4 pages and thats probably streching it

[HenningO]

http://www.diva-portal.org/diva/getDocument?urn_nbn_se_...-216-1__fulltext.pdf (http://www.diva-portal.org/diva/getDocument?urn_nbn_se_kth_diva-216-1__fulltext.pdf)

Should get you started... especially chapter 9

[Denisk31]

HenningO: The link to the document was greatly appreciated, thanks very much.

Penguins2001: Yes the thesis will go into way more depth but I need to complete analytical calculations to get some initial results and dimensions.

I am writing my thesis on the optimised design and manufacture of the restrictor unit and the intake and exhaust systems, for the application of a turbo charger to our formula student racing car. The thesis approach will involve completing initial analytical calculations, as I stated above, which will then be used to create a computational model using Ricardo Wave and Fluent. These models will then be optimised and the results will be used to complete an experimental analysis on a dyno to verify the results obtained from the analytical and computational models.

Again, thanks everyone for your help, it is much appreciated,

Denis

[Mike Claffey]

Howdy Densik I would suggest you spend time modelling with Wave and Vectis instead of fluent, assuming you are doing 3d work. Unless you already have your head around fluent, 3d coupling with wave-vectis will be easier, even if only for availability of documentation and tutorials.

Anyway good luck with your project but be wary about using the words optimised or optimal as it implies you have created the best possible solution. Our cars keep getting better and better, yet every year I read thesis with the word optimal in it http://fsae.com/groupee_common/emoticons/icon_smile.gif

Regards,

Mike