Recent content by jaap de vries

  1. J

    Equation relating mass flow rate to pressure drop

    Ok so you calculated the required flow rate first, that's OK. Tube size mater a lot, small narrow tubes = large head loss. First define you system. How low, narrow, how many bends, are there baffles? then calculate required Reynolds number (Note that temperature change and so does change the...
  2. J

    Best MS Student Calculator for 3rd Year Mech Eng Student

    :smile: I have the TI voyage 200. This is around 200 dollars. First of all I am suprised that nothing better has come up in a while but that has probably something to do with restrictions in the classroom. Most of the basic functions are the same as the TI89. A couple of nice things to...
  3. J

    Effect of Downstream Pressure Fluctuations on Choked Mass Flow Rate

    I thought that wit chocked flow upstream pressure did not effect the flow rate?!
  4. J

    Pro Engineer Files: Find Complex CAD Models for Mechanical Engineering

    That is a good point I do not believe that the student version and professional version can exchange files. I taught myself pro-E and in my opinion. One of the most important, and often least discussed topics is creating 2-D drawings for communicating with a machinist. It is not hard to create...
  5. J

    Material of Airfoils in Wind Tunnel Experiment

    If you want to make a 2-D experiment make sure your span crosses the entire wind tunnel section. If you want to investigate 3-D effects make sure the span does nor exceed 80% of the width of the tunnel. Wind tunnels give you answers about the "shape" of the airfoil and its performance so the...
  6. J

    News Surprise! Netherlands Labeled a 'Tax Haven' by Obama

    Who would have though that our "socialist" country would be labeled as such. http://crossroadsmag.eu/2009/05/netherlands-is-tax-haven-obama-says-dutch-government-astonished-at-tax-haven-branding/ I am sure that this will be rectified soon.
  7. J

    How Does Effectiveness Influence Heat Exchanger Capacity Selection?

    You can calculate the effectiveness. e = q/qmax q max = Cmin (Thi - Tci) Thi is temperature of the hot fluid at the entrance Tci is " " of cold " "
  8. J

    Thermal Diffusivity: Steel vs. Titanium

    Thermal diffusivity measures the ability to conduct thermal energy relative to its ability to store thermal energy (Incropera and DeWitt). It basically tels you how quickly a material responds to changes in their thermal enviroment. It does not say anything about the melting point.
  9. J

    How to calculate Nusselt number

    You may want to restate your problem a little bit. First of, there is no heat transfer through the outer wall. Does this means the pipe is insulated? Is the pipe heated surounded by insulation? Furthermore, what do you mean with free convection here? is there boyuancy driven flow? All...
  10. J

    Can Reynolds Number be Calculated for a Random Point?

    When there is risk of ambiguity, absolutely.
  11. J

    News Texas Governer warns of secession

    His answer was: "If Washington continues to thumb their nose at the American People, who knows what might come out of that...Texas is a unique place" There are answers he could have given to make sure that he would not be considered a secessionist. Why was the interviewer a "left wing nut...
  12. J

    History Republican revisionist history?

    I made the mistake of reading the U-tube comments with the I-am-reading-PF-comments mindset. I will have to remain on PF for a least one hour to restore my faith in humanity.
  13. J

    News Sen. Arlen Specter to switch parties

    That's funny, I drive a 94 Chrystler Lebaron What Factory? :rolleyes:
  14. J

    News Obama & Chavez: Respect Despite Tensions

    This comparison still doesn't make sense (smells like a Godwin). Venezuela is not on the brink of invading any neighboring countries. You conveniently leave out the fact that the country that is about to overrun by extremists is Pakistan and this just happens to be the country that is much more...
  15. J

    News Sen. Arlen Specter to switch parties

    Who the hell are these people that still have land-lines?? Oh, and by the way, did you know the factory warranty of your car is about to run out?
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