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AIAA Propulsion and Energy Forum

Aug 19, 2019 to Aug 22, 2019
Indianapolis, IN, United States
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SwRI will be exhibiting at the AIAA Propulsion and Energy Forum, Booth No. 325

Monday, Aug. 19
9:30 a.m. – 12:00 noon, Room 104
HR-01: Design and Development of Novel Hybrid Rocket Motor Concepts I
Shane Coogan, Chair

11:00 a.m. – 12:00 noon, Room 106
LP-04: Introduction to Sloshing Dynamics in Space Vehicles
Steven Green, Chair

Fluid sloshing forces are a significant consideration in the control and stability of a spacecraft during all parts of its mission. In this tutorial, Steven Green will describe the theoretical foundations of the modeling and testing approaches to estimating the effects of fluid dynamics through the use of mechanical analogs.

Tuesday, August 20
2:45 p.m. – 4:30 p.m., The HUB in the Exposition Hall
“Introduction to Additive Manufacturing”
Nathan Andrews, Paul Gradl (NASA MSFC), Omar Mireles (NASA MSFC)

Additive manufacturing is increasing in prevalence and importance across many industries. This tutorial will provide a thorough introduction to the technologies involved, the typical manufacturing process, common design approaches, and the qualification considerations with using this new technology.

Wednesday, Aug. 21
2:00 p.m. – 4:00 p.m., Room 106
GTE-24: Introduction to Propulsion Simulation Using NPSS and OTAC
David Ransom, Chair

Propulsion system simulation is relevant at all stages of development, from preliminary design through production testing. This tutorial will provide insight into the modeling and analysis of propulsion systems using one of the more common simulation environments. In addition, this tutorial will cover a recent turbomachinery modeling development by NASA Glenn Research Center.

Thursday, Aug. 22
2:00 p.m. – 2:30 p.m., Room 105
LP-28: Propellant Storage and Management III: “Critical Review of Damping Prediction Methods for Annular Ring Slosh Baffles”
Steven Green, Shane Coogan

The lateral sloshing of liquid propellants in launch vehicles is an essential consideration for the guidance, navigation, and control design. The moving liquid mass imparts forces and moments on the tank structure that can destabilize the vehicle if not properly mitigated. Active control through an autopilot system can be a key component to the mitigation, but typically a minimum amount of passive damping is required. Annular ring baffles provide the most mass-efficient damping, and design methods are used to size and space the baffles in propellant tanks so that the minimum damping is always achieved. This study reviews three common design assumptions: that multiple submerged baffles have a cumulative effect on damping, that the Miles equation accurately predicts damping for a single baffle, and that the damping in spheroidal domes can be predicted through an equivalent cylinder approach. These assumptions are tested against four datasets from the literature and are shown to be inaccurate and non-conservative. Updated design assumptions are demonstrated to perform better against the historical data, and these are recommended for future work.

2:00 p.m. – 2:30 p.m., Room 311
AMP-03: Additive Manufacturing Technology: “Geometry and Distortion Evaluations of Additively Manufactured IN718 Internally Cooled Radial Turbines”
Charles Krouse, Nathan Andrews, Grant Musgrove

Conventional methods for manufacturing internally cooled radial turbine blades have been found to be insufficient for reliable part manufacture. With the rise of metal additive manufacturing (AM), in particular, direct metal laser sintering (DMLS) technologies, the potential for manufacturing these complex pieces of machinery is becoming feasible. However, due to the extreme conditions that turbine blades are subjected to, and the tight tolerances required for maximum performance efficiency, it is crucial that the manufactured geometry of the turbine blade be equal to that of the engineering design and blueprint. This is a major challenge associated with the DMLS process, in large part due to print quality dependence on part orientation and the introduction of highly localized temperatures gradients that cause the geometry of the printed parts to undergo distortion and warping. These issues can ultimately result in as-printed geometry that is unacceptably different from the original design. Being able to understand and account for these phenomena is a widely recognized step of the AM design process. This paper provides the details of the as-printed geometry and distortion evaluations for a novel design of an internally cooled radial turbine impeller that is being created at SwRI. A thorough examination of several printed specimens against the original design is reported. Coordinate measuring machine and x-ray Computed Tomography inspection are both utilized to digitize the printed parts. Furthermore, a comparison of the measured distortion is made to computational predictions generated by the ANSYS Additive® software package, which is one of several new tools now emerging in the industry to predict the distortion and provide design assistance for AM printed parts. Overall, it was found that ANSYS Additive distortion predictions qualitatively agreed reasonably well with the measured distortion values.

For more information, please contact David Ransom.