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  1. TDIMeister

    GPU acceleration on ANSYS Fluent 14.5

    To clarify my above post, my laptop has 2GB video RAM and 32GB system RAM.
  2. TDIMeister

    GPU acceleration on ANSYS Fluent 14.5

    Hello, I hope someone here is able to help give me a definitive answer to my queries. Fluent 14.5 has support for utilizing a supported NVIDIA GPUs to off-load some computation tasks from the CPU with an HPC License (which my institution has). What is not clear from the literature I've read is...
  3. TDIMeister

    Making a user-defined curve from equation

    ...rather than a logarithmic spiral (e.g. nautilis shell, hurricanes, etc.) that whose pitch get progressively larger while turning outwards: xt = a*exp(b*t)*cos(Num*360*t) yt = a*exp(b*t)*sin(Num*360*t) Two problems I'm encountering (sorry if these may seem very trivial - my last full-time use...
  4. TDIMeister

    Making a user-defined curve from equation

    ...there are a couple of different forms in cartesian coordinates. Is there a way to do a law curve in polar coordinates? Or using increment indexes, i.e.: x_ij = x_ij-1 + (increment_i)*((ln(W/(2*pi)))*x_ij-1 - y_ij-1) y_ij = y_ij-1 + (increment_i)*((ln(W/(2*pi)))*y_ij-1 + y_ij-1) Thanks again!
  5. TDIMeister

    Making a user-defined curve from equation

    7.5. I also made up an Excel sheet where I can vary the parameters and visualize the results out of an X-Y table. Regards, Dave.
  6. TDIMeister

    Making a user-defined curve from equation

    ...a 2D logarithmic spiral, ultimately to create an extruded body out of it. The equation of this curve is given by: In polar coordinates: r = a*e^(b*theta) or theta = (1/b)*ln(r/a) In parametric form: x(t) = r(t)*cos(t) = a*e^(b*t)*cos(t) y(t) = r(t)*sin(t) = a*e^(b*t)*sin(t)...
  7. TDIMeister

    Higher boost and E85 or Methanol

    BrianPetersen wrote: Regarding cam timing effects, a lot of the muscle-car engines back in the day, and sport motorcycle engines nowadays, get away with 13:1-ish nominal compression ratio simply because they are running so much cam that at lower revs, the volumetric efficiency is lower, so there...
  8. TDIMeister

    Higher boost and E85 or Methanol

    Retarded IVC need not experience a loss in performance (at least compared in magnitude to having to drop x PSI of boost and y degrees of ignition timing on account of knocking). If the intake is properly tuned, the charge backflow from late IVC can be minimized or eliminated where an...
  9. TDIMeister

    Higher boost and E85 or Methanol

    ...blend a small amount to about ~M50 start to start. Calculate your fuel use carefully and observe knocking tendency and progressively add more *pure gasoline* until you are at the threshold of knocking; determine the percent MeOH at that point and that's about where you should be running...
  10. TDIMeister

    Sequential Turbo

    "6. One may wonder if two sequential VGT's will be an ultimate answer." Being done: http://forums.tdiclub.com/showthread.php?t=270527
  11. TDIMeister

    liquid propane fuel system, not vapor.

    Franz, I'm using GDI Injectors but placing them in the intake ports... I thought this was amply clear. We're thinking outside the box, this is not for a passenger car engine application.
  12. TDIMeister

    Do new GDI engines have throttle plate?

    GE-Jenbacher stationary gas engine.
  13. TDIMeister

    Do new GDI engines have throttle plate?

    "A thermodynamic cycle doesn't dictate the mechanism." -Agreed.
  14. TDIMeister

    Do new GDI engines have throttle plate?

    Draw a P-v diagram and you will see how expansion is longer than compression (the latter of which is to include the pre-expansion), which is the intent of the Atkinson -- and Miller -- cycle. Better, find the MTZ article I cited; it will even illustrate the P-v diagram for you.
  15. TDIMeister

    Do new GDI engines have throttle plate?

    In the above reference, the authors use EIVC as Miller and LIVC as Atkinson. Mazda uses the term Miller to denote LIVC with supercharging; Toyota uses Atkinson to denote LIVC in the naturally aspirated Prius engine. You can see that there's no real agreement on the nomenclature convention. A...
  16. TDIMeister

    Do new GDI engines have throttle plate?

    You don't have to agree with me, you just need to read some scholarly work on the subject for yourself: Schutting, E. et al. Miller- and Atkinson-Cycle on a Turbocharged Diesel Engine. MTZ 06I2007 Volume 68.
  17. TDIMeister

    CFD Software to design automotive air-intake...?

    "Some hand calculations and common design sense will suffice to give 95% of the result of a PROPERLY done CFD-developed and -optimised model." The corollary to the above is that an improperly/poorly done CFD-developed manifold could wind up performing worse than the old-fashioned calculation...
  18. TDIMeister

    Do new GDI engines have throttle plate?

    There's plenty of disagreement even in engine circles regarding the distinction between the Miller and Atkinson cycles but they ultimately achieve much the same thing and some even (mistakenly) use the terms interchangeably. The thermodynamic cycles when plotted on P-v and T-S diagrams and the...
  19. TDIMeister

    CFD Software to design automotive air-intake...?

    One can use a super-duper CFD program to design an intake manifold and then commit an epic fail as I witnessed recently: The offender proudly showed fancy screenshots showing streamlines of his manifold design. The fail occurred because he assumed air would be drawing through all 4 cylinders...
  20. TDIMeister

    Do new GDI engines have throttle plate?

    BMW's HP-DI with Valvetronic does not have a conventional butterfly throttle. Valve timing meters the amount of air that goes into the engine. This system runs lambda 1 to be compatible with a 3-way catalyst (TWC). VW/Audi (T-)FSI has a throttle and also runs at lambda one with a TWC. Ditto...

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