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Rocket Nozzle Design. Group Members: Mike Nick. Introduction... Presentation Outline. Introduction (Nick) Brief Theory / FLUENT Modeling (Mike) Literature / Experimental Data (Nick) Conclusion (Mike). Introduction... Project Objectives.
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Rocket Nozzle Design Group Members:Mike Nick
Introduction...Presentation Outline • Introduction (Nick) • Brief Theory / FLUENT Modeling (Mike) • Literature / Experimental Data (Nick) • Conclusion (Mike)
Introduction...Project Objectives To analyze four simplified nozzle geometries in a model rocket and calculate their maximum thrust. Compare the theoretical and experimental thrust of these nozzles. Choose the best nozzle based on our data.
Introduction...Which simplifications? The Nozzle Configurations we modeled: • Orifice • Converging Nozzle • Diverging Nozzle • Converging-Diverging (Click on links above to see the various configurations)
Introduction...Rocket Particulars • The type of rocket we modeled: • Solid Propellant / Core Burning • Core burning rockets burn propellant from the “inside out.” This is in comparison to end-burning rockets which burn propellant from the “bottom up.” Graphic from: http://www.sewanee.edu/physics/SEMINARS/HTML%20Rowland/sld011.htm
Introduction...Rocket Particulars The size of rocket we modeled: 0.25 Inch diameter casing 2) 2.25 Inches Long
Brief TheoryHow to calculate thrust The general thrust equation is given as follows: Graphic from: http://members.aol.com/ricnakk/th_thrst.html
GAMBITThe Mesh Triangular Elements40 to 400 Intervals/Inch
FLUENTAssumptions • Axisymmetric 2D Flow • Steady State / Constant Pressure Inlet • Compressible Flow • Ideal Gas (air)
FLUENTParticular Settings • On all configurations the iterations were run to a residual of 1e-3 • Turbulent Flow (K-E model) • Variable Density • Used 2nd Order Equations to Calculate Density / Pressure / Momentum
Literature The preponderance of literature clearly shows the Converging – Diverging Nozzle as the most efficient nozzle design. Diagrams like this (right) are not uncommon: Graphic from: http://www.nakka-rocketry.net/lambda_p.html
Literature Similar Pressure Trends
Experimental DataIntroduction Homemade rockets with these four various nozzle geometries were built and tested. All thrust values were measured and recorded.
Experimental DataExperimental Setup Method #1 Method #1 In this case the nozzle thrust was downward onto the scale. Before ignition, a thin metal plate was placed on top of the scale to protect it from the flame.
Experimental DataTesting Using Method #1 For record keeping, a camcorder was zoomed up close to the scale and recording. Note the metal plate protecting the plastic of the scale.
Experimental DataExperimental Setup Method #2 Method #2 In this case the nozzle was placed into a hollow tube and thrust was directed upward. Thus the rocket pushed onto the scale.
Experimental DataTesting Using Method #2 Note the camcorder was zoomed up close to the scale. (Right) Movie of Converging-Diverging Run: Click on Image to Play
Experimental DataData Using Method #2 We were able to go back and watch our results on TV in slow motion.
