An engineering model for effects of helical fuel ports on hybrid fuel regression rates is developed and compared with test results for five different helical fuel grain geometries. The tested grains were additively printed from acrylonitrile butadiene styrene and burned in gaseous oxygen at 200 psia chamber pressure. Regression rate amplification above the nominal cylindrical port regression rate is calculated as the product of two multipliers: 1) one due to a helix-induced skin friction increase, and 2) another due to helical flow suppression of radial wall blowing. The first multiplier is based on an existing skin friction correlation, modified to account for diminishing helical centerline radius of curvature as the fuel burns and the port becomes increasingly cylindrical. The radial blowing suppression multiplier is derived as the ratio of centrifugal force due to helical flow to radial momentum out flow of ablated material from the fuel wall. Calculations show that approximately 75% of the regression rate amplification results from skin friction increase due to helical rotation. The remaining amplification results from centrifugal flow suppression of radial wall blowing. Statistical analysis of the model/data residuals demonstrates better than 4% mean fit error over mass flux levels ranging from 2.0 to .
Engineering Model for Hybrid Fuel Regression Rate Amplification Using Helical Ports
Journal of Propulsion and Power ; 33 , 2 ; 398-407
2017-03-01
Conference paper , Article (Journal)
Electronic Resource
English
Engineering Model for Hybrid Fuel Regression Rate Amplification Using Helical Ports
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