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  • Users: Pkruse
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  1. P

    Wood burning train

    Locomotives and ships converted away from coal and wood burning engines mostly because the labor costs were much less with either a diesel or a gas turbine. This is the same reason ships got rid of their sails.
  2. P

    Power Transmission, Gear, Pulley

    Lots of ways to do that. The question is which means works best for this application. But then you have not told us anything about this application except the input and the output. The idea to look into block and tackle design is a good one, and the most obvious. But by the time you figure...
  3. P

    Air burst testing with concrete (scaled down)

    Sounds like you might have to build a pneumatic cannon. Maybe with an intensifyer.
  4. P

    Joint design for assembly

    There are many different ways to model a bolted joint, some very complicated. You might check out Bickford if you have an interest in those details. But to keep it both simple and safe, first find the shear strength of the bolts if you have a shear joint, or the tensile strenth if it is a...
  5. P

    Most used mathematics for engineers?

    Simple arithmetic is the most common for me. Can't get the job done without an excellent intuitive understanding of Algeria and calculus.
  6. P

    Analysis of Lifting Hook for Rolled Cans

    The steels uses in gas and steam turbines are selected from a long menu in the Boiler Code. While identified differently, some are the same steels used in structures. The big difference is in the control of processing and certification. Many are forged, and therefore identified differently...
  7. P

    Analysis of Lifting Hook for Rolled Cans

    AlephZero is right. Steam turbines operate at much lower temperatures and typically don't have a high speed shaft like most gas turbines. So they use a lot of steel. They are designed typically for a longer fatigue life, but they do have creep and fatigue limits similar to gas turbines. I...
  8. P

    Analysis of Lifting Hook for Rolled Cans

    You won't see ASTM A-36 called out on many gas turbine drawings, but most of the steel alloys in the Boiler Code have found their way into one GT or another. Keep in mind that the super alloys in the turbine section all have properties similar to steel, except with regard to high temperature.
  9. P

    Analysis of Lifting Hook for Rolled Cans

    Many gas turbines have a great deal of steel structure in them. Everything I said about jet engines applies to them. But another idea that might optimize the flow of work is to get rid of the lower beam and put a hook on one end similar to a sorting hook. Then put an over center clamp on...
  10. P

    Analysis of Lifting Hook for Rolled Cans

    I've run into hook height problems many times, and you are going down the correct path to solve that problem. Make your lower beam long enough to extend all the way thru the cylinder. Put a small stop on the end so the cylinder can't slide off. I'd probably use I-beams for the top and bottom...
  11. P

    Did you have to give up everything else for engineering?

    I've been watching to see which new engineers get hired. Not the ones who did "fine." They are looking for engineers who have incorporated engineering into all aspects of their lives. I've had several recruiters tell me that the school records are important, but the single most important thing...
  12. P

    Analysis of Lifting Hook for Rolled Cans

    Well, you found most the requirements. Don't forget OSHA 1910 and 1926, whichever is applicable. Keep in mind that case law and interpretations often sends you to 1926 when you think you should be in 1910. You will need a means of positive retention so the load does not slip off. I've...
  13. P

    Analysis of Lifting Hook for Rolled Cans

    I worked in the rigging business for 25 years and never head of anyone designing their own hook. In many places, it is illegal or else they make it very expensive for you to do so legally. I normally start with Once I find what I want, I do a Google search to see if...
  14. P

    Impact what? Force or Energy?

    I don't know enough enough about brick walls to speak concerning that, but in gas turbine design we have to make sure the case is strong enough to contain a blade if one were to break free of the disk. We first bracket the solution with hand calculations based on strain energy. That drives the...
  15. P

    How do you join metal and metal (steel to aluminum)

    Brazing steel is pretty easy. Brazing aluminum is a mysterious art for someone who has never done it. But if you have a desire to learn, you can get good information from your welding supplier, or search the web. The trick is to match the right materials, rod material, and temperatures. You...
  16. P

    Why does gas turbine efficiency increase with size?

    For small engines, centrifugal engines are more efficient. For large ones, axial is more efficient. You can plot the efficiency curves for both as a function of size. Both will show increasing efficiency with increasing size. But at some point at about a thousand HP, the curves cross...
  17. P

    Why does gas turbine efficiency increase with size?

    Tip clearance will be about the same in large and small engines. The problem is leakage around the tips wastes energy, so we always minimize that. But energy lost around the tips is a much larger percentage of the total in the smaller engine. The answer to the second question is that the...
  18. P

    Used oil reused

    I experimented with this more that 4 decades ago. Sorry, I have not kept any data from that. In small gas engines, I found that if I got them good and hot running on gasoline, then I could switch over to oil and they would run just fine, with no black smoke. Heavy fuel diesel engines, like...
  19. P

    Used oil reused

    You can boil the oil and the vapors can be made to burn cleanly. But then you end up with a lot of crappy left over that does not boil off. Many over the road trucks burn oil mixed with diesel fuel and meet all EPA requirements. Diesel engines sold as "heavy fuel" will even burn roofing...
  20. P

    Why does gas turbine efficiency increase with size?

    There are many answers to this question, but by far the most important is tip clearance, which is a major source of lost energy. The smaller the clearance, the lowered the loss. But tip clearance cannot be scaled down as the engines get smaller. Very small axial engines become so inefficient...
  21. P

    Is it possible to connect two hydraulic jacks?

    I've manifolded jacks together many times, lifting as much as 800 tons. But they will all see the same pressure. This can be a problem if they do not also see the same load. So install a shut off valve in front of each jack to control the fluid going to that jack individually.
  22. P

    When will a Pipe Burst

    Your concern is in the difference in pressure.
  23. P

    Final Temperature of Combustion Gases

    With a great deal of time, money, and effort the gas turbine industry has hit a limit of 3500-4000 degrees F. That requires the use of high temperature super alloys and propriety coatings. Since that is much higher than the melting point of the alloys, they also use very creative methods to...
  24. P

    Broken Concrete as Fill versus Soil

    Either works as fill. Both need to be compacted. They do that with a big roller machine that vibrates.
  25. P

    Semi Truck Heavy Haul Trailer Axle Spacings

    Axles can be rated for much more than 12kips. That is part of the design engineer's job to specify how much capacity he/she needs. But if it is to haul heavy loads on the road, then the maximum axle capacity will be specified by whichever DOT has jurisdiction. 20-24 kips per axle is quite...
  26. P

    Semi Truck Heavy Haul Trailer Axle Spacings

    I'd use a spread sheet, unless I thought ANSYS work bench would better impress the customer.
  27. P

    Need a rigid insulation material?

    Bobbywhy's idea is good if you are looking for electrical insulation. But if you are looking for thermal insulation you have two good choices. Both the choices are basically the same, but from two different products sold by two different sources. One is to use foam core material sold though...
  28. P

    How should I switch an air conditioner off?

    And when your starting capacitor runs out of electrons, you will have to buy a box of electrons to refill it. I heard that equally silly statement from another technician. I just smiled and thanked him for his advice. My dad taught me well that everyone has a constitutional right to be...
  29. P

    How to determine actual tention applied in a steel wire

    Also, you don't supply enough information. Need to know how much sag, which will change with temperature. To figure that, we also need more details on the rope properties.
  30. P

    India Engineering Powerhouse

    I've been wondering that myself. I'm extremely impressed with the Indian engineers working in the US. They tend to be very excellent. But I've not been impressed with Indian engineers working in India. They say they are engineers, but I see no evidence of it from their work. That is...
  31. P

    Question from a non-engineer: Pulley Systems

    I found all the parts you need in the rock climbing section of the Campmore web site. I'd recommend a kernmantle static line. Good wear resistance with little stretch. Also works well with a sailboat cam cleat to secure the line.
  32. P

    Question from a non-engineer: Pulley Systems

    Getting close. The ropes attached to each end of the rod must go straight up, each to its own pulley. Then you can route them through as many pullies as you need to bring them together at a common location. At that point you tie them together and connect them to the hoist line. It works well...
  33. P

    Question from a non-engineer: Pulley Systems

    A slight variation to that idea works better. I've used it in many material handling designs. Use two ropes, but attach them to a third rope that terminates on the hoist drum. Or the first two ropes can be one rope with each end attached to opposite ends of the rod. The idea in this picture...
  34. P

    Distributed Power

    They installed the generators at our site about three miles from their site. They could not install them at their site because their permit was max'ed out. But we were not the only company that got such a deal. Thanks for all the information you added.
  35. P

    Distributed Power

    You caught me in a typo. DP distributed power DR typo. Should be DP LS load shedding Some use the term DG for distributed generation.
  36. P

    Power factor question

    Pwr comes to us in three phases, each 120 degrees out of phase with the next. We derive pwr by flowing current between the phases. If the phases change from their ideal 120 degrees, you still have full pwr flowing thru each phase, which is what we get charged for. But we now have slightly...
  37. P

    YOU!: Fix the US Energy Crisis

    Of course you are right. I see so many ways that we could be more efficient, and we will be so in the future. But that has been the general trend over the last several decades. Everything is more efficient than it used to be, yet we are using a whole lot more energy. The reason being that...
  38. P

    YOU!: Fix the US Energy Crisis

    This note will start out summing up a negative situation, and then will then show reason for hope toward solving this mess and even growing to greater heights. I’ve been a strong advocate of finding alternant energy sources since the early 1970’s. From time to time, I’ve had the privilege...
  39. P

    Distributed Power

    I attended a lecture on DP yesterday, and learned some new things that I thought I'd share. If anyone has something to add on this topic, then please post. DR is when you install a generator at its point of use, like perhaps a 20 MW unit at a hospital or hotel. Payback is often as short...
  40. P

    Microturbine Exhaust Cooling

    That would normally mean increasing the number of turbine stages.
  41. P

    Gear box casing design

    Different materials have different properties. The task is to select the one that best meets your design objectives. Sometimes that may be one of many iron choices, sometimes steel or something else. Some iron is strong and tough, some very brittle. So the question cannot be answered in such...
  42. P

    Microturbine Exhaust Cooling

    In the gas turbine industry, a very hot exhaust is the first indicator that we have done a poor job of extracting the available energy, but somethimes cannot be avoided. Keep in mind that a simple diffuser will drop the temperature a great deal. As for fitting my boat ideas into a car, I can...
  43. P

    Microturbine Exhaust Cooling

    I rather like the idea of using the car body as a heat sink and a heat exchanger. My boat design did just about everything except that. If I had used a heat exchanger in the keel, then I guess that would have been similar. This was an air cooled diesel engine with no water based coolant at...
  44. P

    Microturbine Exhaust Cooling

    I once had to do a design for a customer who wanted a large air-cooled turbocharged diesel mounted in the bilge of a wood boat, with a dry stack and no seawater cooling. We had to keep the temperatures in the engine room much lower than I at first thought possible. I found very excellent ideas...
  45. P

    Microturbine Exhaust Cooling

    Mix it with a huge volume of ambient air.
  46. P

    Traits all engineers share?

    AK: Quote away. Sounds like an interesting project. I'd like a like when you have something ready to see.
  47. P

    Traits all engineers share?

    A propensity toward rational thought helps a lot. The educational process is designed to weed out the worst offenders lacking that skill. That is why you get Calculus up front and perhaps 50 students will sign up for the class and maybe fewer than ten will complete the class successfully...
  48. P

    Calculation of Permissible Jib Crane Load

    Not enough information here to complete the design. Need to know the nature of the connection between the column and the beam, which of the H-beams you are using, and its material. This is not an offer to do the design for you, but these are important things to know before proceeding further...
  49. P

    Where can beginners learn shop skills?

    I got my shop skills two ways. I made friends with lots of people who had extensive home shops. Some were fully equipped machine or carpenter shops. I volunteered to help them with their projects. Built air boats, engines, furniture. Did auto body work, welding, gun smithing, and casting...
  50. P

    The whys of Combined Cycle power plants

    This thread on gas turbines has pretty well run its course. I suggest you open a new thread on steam turbines, & maybe one on heat exchanges. Both of your questions are interesting.