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Post by hassanalawi on Mar 21, 2020 8:57:02 GMT -5
Hi everybody, What are the scientific justifications on jetspecs calculations and given parameters such as the flame tube length & dia, air gap, zones holes pecentages?
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Post by racket on Mar 21, 2020 18:00:27 GMT -5
Hi
Jetspecs was created to help guys make a running engine first time despite the multitude of variables associated with a virtually infinite number of turbo configurations, fueling types and level of manufacturing skills , the parameters were arrived at after years of helping guys get their troublesome engines to run , they aren't perfect but they do the job .
If you want to be "scientific" then there are a number of weighty Texts that will provide the "scientific justifications" you desire, but be prepared for many hours of study time if you want to produce a "correct" combustor with all the parameters scientificly justified .
Cheers John
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Post by hassanalawi on Mar 25, 2020 12:00:47 GMT -5
took members suggestions on using propane only since my turbo is small these will be the new hole sizes, 1 row for each zone, each row is placed half way of each zone....what do you think? also, i have been looking hard for a suitable universal 12v oil pump, any suggestions?
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Post by racket on Mar 25, 2020 16:01:19 GMT -5
Shurflo 8000-643-236
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Post by hassanalawi on Mar 25, 2020 17:12:44 GMT -5
Hi John, thankx What do you think about the new design up there?
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Post by racket on Mar 25, 2020 17:52:07 GMT -5
OK
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Post by hassanalawi on Mar 28, 2020 10:54:16 GMT -5
so finally sketched the final design in solidworks The middle hole at the second picture (flange) is for propane delivery tube while the right one is the spark plug inlet
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Post by hassanalawi on May 1, 2020 6:46:32 GMT -5
hello guys, any thermodynamic analysis examples available to calculate different temperatures, pressures and velocities
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Post by turboron on May 1, 2020 7:19:29 GMT -5
hassanalawi, study( lots of info online) the following to be able to perform 2D gas turbine performance calculations:
1) The Continuity equation - Density times Area times Velocity = Constant 2) The Perfect Gas law - pressure times volume = compressibility factor times (the Universal Gas Constant/Molecular Weight) times the Temperature 3) Euler's equation - Head = Head coefficient times the tip speed squared 4) Horsepower = Mass flow times (the heat coefficient at constant pressure) times the temperature difference
A single paper or book on gas turbine performance should show you the way.
Thanks, Ron
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Post by hassanalawi on May 1, 2020 8:53:03 GMT -5
hassanalawi, study( lots of info online) the following to be able to perform 2D gas turbine performance calculations: 1) The Continuity equation - Density times Area times Velocity = Constant 2) The Perfect Gas law - pressure times volume = compressibility factor times (the Universal Gas Constant/Molecular Weight) times the Temperature 3) Euler's equation - Head = Head coefficient times the tip speed squared 4) Horsepower = Mass flow times (the heat coefficient at constant pressure) times the temperature difference A single paper or book on gas turbine performance should show you the way. Thanks, Ron thankx turboron, whats worrying me is my turbocharger because not enough data is provided by the manufacturer, so thought there might be some examples to show how to find the needed data to carry on the calculations
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Post by turboron on May 1, 2020 9:20:34 GMT -5
hassanalawi, you posted on March 15 the data you need for a first order performance calculation. Using your compressor inducer diameter calculate a inducer area. The mass flow will be approximately 11 times the inducer area in square inches. Once you have the mass flow you can calculate a first order horsepower using equation 4) which I provided. Assume a temperature difference of 300 degrees F (1450 turbine inlet minus 1050 exhaust).
Thanks, Ron
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Post by hassanalawi on May 2, 2020 18:05:01 GMT -5
hassanalawi, you posted on March 15 the data you need for a first order performance calculation. Using your compressor inducer diameter calculate a inducer area. The mass flow will be approximately 11 times the inducer area in square inches. Once you have the mass flow you can calculate a first order horsepower using equation 4) which I provided. Assume a temperature difference of 300 degrees F (1450 turbine inlet minus 1050 exhaust). Thanks, Ron Thanks for your help Ron Is there anybody who has done the whole calculation, i ve been really lost the couple of weeks looking at different books and articles and it looks like each has his own way of doing an actual Brayton cycle analysis for our application, each takes different assumptions that you cant really understand or know where they came from, just gave up lol thats why i m here. I really want to understand the assumptions i need to make, the analysis, calculations of temps, pressures, exit velocity, thrust..etc. Regards, Hassan Alawi
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slittlewing
Senior Member
Joined: November 2017
Posts: 458
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Post by slittlewing on May 2, 2020 18:17:09 GMT -5
Basic fuel system - Bosch 044 pump (or copy) delivering max pressure of 10 bar. Normal car fuel pump is not high enough pressure. Connect this through a 3 way ball valve, one leg goes back to the pump inlet and the other to the injection nozzle. You can vary pressure by how much you return to the pump inlet. Cheers Scott
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Post by racket on May 2, 2020 18:23:50 GMT -5
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Post by hassanalawi on May 2, 2020 18:36:56 GMT -5
Thankx John
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