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  1. JKEngineer

    Internal Natural Convection in a horizontal pipe containing Jet A

    If a day tank or heat exchanger in line with the supply system is too long a project then I think you are back to using temperature probes. these would be best in the fuel, which is the nightmare I referred to earlier. An alternative would be to back up what temperature readings you can get...
  2. JKEngineer

    Internal Natural Convection in a horizontal pipe containing Jet A

    You could fill a "day" tank with fuel and adjust its temperature to approximate the ground T instead of being at 95F, which I am assuming is being driven by the outside summer temperatures in Las Vegas. Then provide that fuel to the pipe as you fill the last x number of planes, sufficient to...
  3. JKEngineer

    Heat Transfer / thermal radiation

    I'm missing something here. For one, I don't understand what a 50% air flow is. However, your initial problem statement sounds like you are treating the problem like a conduction through air calculation. I don't think that's appropriate. You have air flowing around the system, so there is...
  4. JKEngineer

    Internal Natural Convection in a horizontal pipe containing Jet A

    Just caught up with this. If I understand correctly, you are testing pipe with hotter than surroundings liquid over a period of time of about 1 hour. It has been suggested that you use T probes for the fluid, which makes sense, but could be both a nightmare to implement and still leave some...
  5. JKEngineer

    Heat transfer at electrical lug connections.

    This is a link to a brochure on my website (which does not have an on-web link) that has two images from the FEA analysis I did of heating in an electrical component. This is strictly as a demonstration of the output obtained using the heat generation on the mating faces. BTW, this was done...
  6. JKEngineer

    Heat transfer at electrical lug connections.

    dbecker - I just saw this thread, so I'm coming to the conversation a little late. By way of background, I do both thermal imaging and heat transfer analysis using FEA and CFD methods. I don't use ANSYS, so am not familiar with the details of its setup. Here are some comments: (all...
  7. JKEngineer

    What is the temp of this? I need an equation.

    I don't think it has any chance of working. Your distances are NOT so large as to be able to neglect convection. I am sure that there are physical methods to measure the distances. Jack Jack M. Kleinfeld, P.E. Kleinfeld Technical Services, Inc. Infrared Thermography, Finite Element...
  8. JKEngineer

    What is the temp of this? I need an equation.

    ducatidd, You really need to tell us more. What approximate distances are involved, what sizes. What temperatures are we dealing with? You say the circle is in the furnace and the rectangle is a heat sink. Then you say that the temperature of the rectangle is too high to deal with...
  9. JKEngineer

    What is the temp of this? I need an equation.

    If you restrict the exchange between them to radiation, then the equations for transfer between them "simplify". ("" means: sort of) You need to deal with the emissivity of each surface and the view factor between them. In addition, assuming a steady state condition, you will need to write...
  10. JKEngineer

    continuous measurement of cast iron stream

    The temperature can certainly be measured. I am not sure if the accuracy you want can truly be attained, since it depends on both the instrument and knowledge of the conditions and properties. I suspect you can get quite close. Jack Jack M. Kleinfeld, P.E. Kleinfeld Technical Services...
  11. JKEngineer

    Using Thermography for Masonry NDT

    It's a well established application. Lot of companies use it. Others aren't as smart. Jack Jack M. Kleinfeld, P.E. Kleinfeld Technical Services, Inc. Infrared Thermography, Finite Element Analysis, Process Engineering www.KleinfeldTechnical.com
  12. JKEngineer

    3D Thermal Data?

    If the materials are uniform then I think heat transfer simulation would be a far better way to go to generate the 3D animation. You would need the properties of the materials to do that. If the properties are not readily available, you could measure them with appropriate dedicated...
  13. JKEngineer

    Need Airflow Analysis on Blower Nozzle

    He appears to be reducing the flow area by a significant fraction. (I am having trouble following your dimensions - not sure how a 9.5"ID from a 10"OD, implying 0.25"wall translates to a 16" width becoming a 14" width. ) It is likely that some stratification will occur. It will be affected by...
  14. JKEngineer

    Under-performing Business Partner

    An alternative is to look at how the billing is broken up. If there is value to the marketing and value to the "work", then P2 should be getting some compensation for bringing in the work, as well as doing the work that P2 actually performs. If you are all getting the same rate for work now...
  15. JKEngineer

    Hiring your spouse

    In addition to the explanations you got above, I would add the following. $5000 seems high for an identity package, unless it includes printing of letterhead and other materials, or includes extensive brochure development. If it does, I would suggest you consider starting smaller. You do...
  16. JKEngineer

    Surface to Air transfer

    The very interesting links (hence the star) provided by kenvlach point out that radiation can actually be a significant factor depending on the actual emissivity, or surface condition, of the bus bar(s). If they are in "like new" condition the emissivity will be low and radiation will be less...
  17. JKEngineer

    Surface to Air transfer

    sailoday: Not sure whether it would be or not. I will admit to not having followed yours carefully enough to tell. [sleeping2] Jack Jack M. Kleinfeld, P.E. Kleinfeld Technical Services, Inc. Infrared Thermography, Finite Element Analysis, Process Engineering www.KleinfeldTechnical.com
  18. JKEngineer

    Surface to Air transfer

    I agree that the value you cite of 18 BTU/h ft2 F is way too high, a more likely value, as cited by IRStuff, is of the order of 1.25 BTU/hft2, or lower. ASHRAE often cites values of this order at low velocity for air, but they usually include a component for radiation. ASHRAE adds that...
  19. JKEngineer

    should an engineering firm be a private Ltd or a corporation?

    Check the legal requirememts for your locality (your state if in the US). You may be legally restricted in the type of business entity that you can form if you are providing engineering services. Jack M. Kleinfeld, P.E. Kleinfeld Technical Services, Inc. Infrared Thermography, Finite...
  20. JKEngineer

    Heat absorber

    I think that the wikipedia article (from what you have said, not from reading it) indicates that the materials surrounding the exhaust are conductive -- so that they take heat away ("absorb") from the gas and deliver it elsewhere -- not hold it. Thermal equilibrium is based on temperature...

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