RICARDO WAVE analysis

[Nishant_iitd09]

hi friends,

can anyone sort out my small problem.
does the experiment done on ricardo wave depends on the maximum and minimum value assigned to the variables in the experiment??
i m working on ricardo wave analysis of intake restrictor. whenever i change the diffuser or collector length(min and max values of these variables), the result gets changed, means the maximum torque comes out at different values of lengths.

sometimes,keeping everything same(variables and their minimum and maximum values), when we re-execute the experiment it might happen that initially it had error but after re-execution there is no error. does it really happens in ricardo??

kindly reply soon.

thanking in anticipation.

Nishant Jaiswal
IIT Delhi.
nishant09iitd@gmail.com

[Nishant_iitd09]

hi friends,

can anyone sort out my small problem.
does the experiment done on ricardo wave depends on the maximum and minimum value assigned to the variables in the experiment??
i m working on ricardo wave analysis of intake restrictor. whenever i change the diffuser or collector length(min and max values of these variables), the result gets changed, means the maximum torque comes out at different values of lengths.

sometimes,keeping everything same(variables and their minimum and maximum values), when we re-execute the experiment it might happen that initially it had error but after re-execution there is no error. does it really happens in ricardo??

kindly reply soon.

thanking in anticipation.

Nishant Jaiswal
IIT Delhi.
nishant09iitd@gmail.com

[Tom W]

Others will have much more knowledge than me, but I think the key word in your post is restrictor.

Wave is 1-D, my understanding from what others have told me is that 1-D (and 2-D) CFD cannot cope with our restrictors, previously there have been a number of posts that have talked about people using various work-arounds to get a working restrictor model into a wave model but I don't remember anyone ever claiming that they have directly designed a restrictor in wave.

The best advice I can give is to get rid of your restrictor model and see if you still get the same errors.

[Nishant_iitd09]

hi friends,

what does the graph of duct signify in the experiment analysis panel of RICARDO WAVE.

when we run an experiment, experiment analysis panel pops up. there is a list of graphs that can be maximized. this list has all ducts tabulated, when we click on any duct name, it gives a graph. what does dis graph shows, this is respect to what wid RPM.

[Pete G]

Hey Nishant

When performing an experiment on wave, it solves for the min, max and mid point values of your variables and predicts outputs based on these results. The closer your min and max values, the more accurate the predictions will be.

When you have chosen values you like, you can click on verify fit and wave will solve for those values of your variables.

There are a number of duct graphs outputted by wave, for a lot of different things, e.g. mass flow, air temp, etc, try looking on wave help to see what all the syntax means.

And i have to agree with Tom, wave is not the best tool for restrictor design, your better off using a 3d cfd software package.
We use ansys cfx for our restrictor design.

Hope this helps

[samphlett]

When the experiment is finished, you are presented with all summary variables. Some may be worth studying, others maybe not.

[Nishant_iitd09]

hi,

the procedure that we are following:
1> Meshing the CAD on webmesher.
2>transferring the MESHED 1 on wavebuild,
3>run the experiment on required variables.
4> finally output is graph btwn torque and RPM, then we maximize d curve for torque.

what to do after this??

how we will decide wich model is better?


kindly help us in dis regard, thanking in anticipation.

yours truely
Nishant Jaiswal

[The_Man]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Nishant_iitd09:
what to do after this??
</div></BLOCKQUOTE>

You see if the Torque-RPM curve you have generated is close to the one you have in reality.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Nishant_iitd09:
how we will decide wich model is better?
</div></BLOCKQUOTE>

The model which produces the curves that is most closest to reality is the best in terms of accuracy.

[Zac]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">what to do after this??

how we will decide wich model is better? </div></BLOCKQUOTE>

Well, what are you trying to evaluate with your simulation?

[Nishant_iitd09]

i dont to evaluate,

i want to check different types of INTAKE model, and which one is the best among those models. thats it!!!

[Zac]

how are you defining best?

[Nishant_iitd09]

best means..... the model which fufill the required torque v/s rpm curve.

[TorqueWrench]

Alright I think there is a bit of stuff being lost in translation.

I think Zac is trying to say, what are you defining as the best torque/power curves? All low down torque, all top end HP, or a broad torque band that compromises?

You pretty much need to go through, weight your options and choose the solution you see as the best answer. I haven't yet seen an agreement between teams as to what this is as every car is different.

[Nishant_iitd09]

how we can do the engine simulation for the engine rpm greater than 8000rpm. do we need to increase the cases?
how do we set the different constants of constant table in different cases?

[Charlie]

The biggest issues I have seen with Ricardo is convergence. Most people do not run enough cycles to have proper convergence. The standard models do not have restrictors, and are set to run at a certain number of cycles. These cycles are not enough to converge a system with an air restrictor, especially with a large plenum. So, look at your intake pressures along the system and see how many cycles you need to get convergence. You can set up a convergence case that is dependent on intake pressures, this is the most successful way I've modeled intake restrictors.

WAVE actually handles intake retrictors pretty well when properly set up, but the example models are not created in this way.

If you are just trying to test the best intake system on a WAVE model without seeing if it is converging or matching a real engine, you are wasting your time and way ahead of yourself! Stop trying to work on a result and get your model right first and foremost.

[samphlett]

The word "convergence" is probably a bad one. Settled into a cyclically repeating state is more like it. People running WAVE models should really be plotting cyclic quantities against either cycle number or time to get a feel for how long their engine takes to settle. Automatic "convergence" detection can be fooled.

[Nishant_iitd09]

hi friends,

Is there any book or something like that from where we could expertise in this RICARDO wave.

Problem: the graphs that we are getting for torque v/s RPM is having a valley at 5000rpm. our whole engine parameter calculation is at 7000rpm. there is a sharp decrease of around 2 units at 5000rpm as compared to 6000 and 7000rpm. so can you suggest how can we resolve this out.

Nishant Jaiswal
nishant09iitd@gmail.com

[Charlie]

You need to find a book about acoustics or intake design / development.

WAVE is just a tool to do that work. If you have questions about WAVE you ask your Ricardo rep, or you may post here.

[samphlett]

If you want a book (or two) about the fundamentals of manifold design, take a look at the publications of Winterbone and Pearson. Not cheap, but good. For example:

"Design Techniques for Engine Manifolds: Wave Action Methods for Ic Engines"

[Nishant_iitd09]

Hi friends...

i have following in my run check, can u please help me out..... i m running over this problem for last 5 hrs.

"F*** JUNCTION e-collectortailpipes_1_duct_4 : THROAT DIAMETER AT DUCT secondary_pipe_1_duct_3 IS LARGER THAN THAT OF THE DUCT ITSELF"

Nishant Jaiswal
nishant09iitd@gmail.com

[Charlie]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Nishant_iitd09:
Hi friends...

i have following in my run check, can u please help me out..... i m running over this problem for last 5 hrs.

"F*** JUNCTION e-collectortailpipes_1_duct_4 : THROAT DIAMETER AT DUCT secondary_pipe_1_duct_3 IS LARGER THAN THAT OF THE DUCT ITSELF"

Nishant Jaiswal
nishant09iitd@gmail.com </div></BLOCKQUOTE>

That appears pretty self explanatory. Find that pipe and see why it's throat diameter is larger than it's connecting duct.

[Drew Price]

F*** Junction?

That was my nickname in college....



Best,
Drew

[Jaydeep]

Hi,
I am working on CBR250RR engine for the camshaft analysis. can anyone help me to give me advise that from where I can get the valve lift value for the different angles.
I also got the 65HP@19000rpm. Now what should I change in the my wave model to get the accurate torque. Please help me I really need this to solve as soon as possible because I am working on this since 2 months.
Thank you