SMARTech Collection: Aerospace Systems Design Lab Publications

Preliminary Design of a 2D Supersonic Inlet to Maximize Total Pressure Recovery

Mon, 29 Aug 2005 22:58:59 GMT

Title: Preliminary Design of a 2D Supersonic Inlet to Maximize Total Pressure Recovery

Authors: Ran, Hongjun; Mavris, Dimitri N.

Abstract: This paper provides a method of preliminary design for a two-dimensional, mixed compression, two-ramp supersonic inlet to maximize total pressure recovery and match the mass flow demand of the engine. For an on-design condition, the total pressure recovery is maximized according to the optimization criterion, and the dimensions of the inlet in terms of ratios to the engine face diameter are calculated. The optimization criterion is defined such that in a system of (n-1) oblique shocks and one normal shock in two dimensions, the maximum shock pressure recovery is obtained when the shocks are of equal strength. This paper also provides a method to estimate the total pressure recovery for an off-design condition for the specified inlet configuration. For an off-design condition, conservative estimation of the total pressure recovery is given so that performance of the engine at the off-design condition can be estimated. To match the mass flow demand of the engine, the second ramp angle is adjusted and the open/close schedule of a bypass door is determined. The effects of boundary layer are not considered for the supersonic part of the inlet, however friction and expansion losses are considered for the subsonic diffuser.

Description: Presented at the AIAA 5th Aviation, Technology, Integration, and Operations Conference (ATIO), 26 - 28 September 2005, Arlington, Virginia.

Niched-Pareto Genetic Algorithm for Aircraft Technology Selection Process

Tue, 29 Aug 2006 22:58:59 GMT

Title: Niched-Pareto Genetic Algorithm for Aircraft Technology Selection Process

Authors: Patel, Chirag B.; Kirby, Michelle Rene; Mavris, Dimitri N.

Abstract: Design of any complex system entails many objectives to reach and constraints to satisfy. This multi–objective nature of the problem ensures that the technology solution is always a compromise between conflicting objectives. The purpose of this paper is to demonstrate the application of Niched Pareto genetic algorithm as a relatively fast and straightforward method for obtaining technology sets that are distributed along the Pareto frontier in objective space. In this implementation, the genetic algorithm is wrapped around a technology evaluation environment to efficiently evaluate various technology combinations. Some of the major challenges include formulation of Pareto domination tournament and sharing function of Niched Pareto genetic algorithm for a technology selection problem, extracting Pareto front from population of the final generation and visualizing the results.

Description: Presented at the 11th AIAA/ISSMO Multidisciplinary Analysis and Optimization Conference, 6-8 Sep. 2006, Portsmouth, VA.

The Need for a Military System Effectiveness Framework: The System of Systems Approach

Fri, 28 Sep 2001 22:58:59 GMT

Title: The Need for a Military System Effectiveness Framework: The System of Systems Approach

Authors: Soban, Danielle Suzanne; Mavris, Dimitri N.

Abstract: The need for a comprehensive framework for the analysis of military system effectiveness is presented. Changes in the world’s economy and its effect on decision making is discussed, as well as the three primary ways decision makers use information: resource allocation, requirements definition, and trade studies between system components. “System” and “system effectiveness” are clearly defined. The idea of a system of systems formulation for military system effectiveness analysis is presented, discussing the need to expand the consideration of the system from the vehicle (engineering) level to the theater or campaign level. The use of probability theory as part of the methodology is defended. Finally, an intuitive overview of the proposed methodology is presented, in a step by step manner. The methodology is called POSSEM (PrObabilistic System of Systems Effectiveness Methodology).

Description: Presented at the 1st AIAA, Aircraft, Technology Integration, and Operations Forum, Los Angeles, CA, October 6-18, 2001

HTS Motors in Aircraft Propulsion: Design Considerations

Sun, 29 May 2005 22:58:59 GMT

Title: HTS Motors in Aircraft Propulsion: Design Considerations

Authors: Masson, Philippe J.; Soban, Danielle Suzanne; Upton, Eric George; Pienkos, Jules E.; Luongo, Cesar A.

Abstract: Current high temperature superconducting (HTS) wires exhibit high current densities enabling their use in electrical rotating machinery. The possibility of designing high power density superconducting motors operating at reasonable temperatures allows for new applications in mobile systems in which size and weight represent key design parameters. Thus, all-electric aircrafts represent a promising application for HTS motors. The design of such a complex system as an aircraft consists of a multi-variable optimization that requires computer models and advanced design procedures. This paper presents a specific sizing model of superconducting propulsion motors to be used in aircraft design. The model also takes into account the cooling system. The requirements for this application are presented in terms of power and dynamics as well as a load profile corresponding to a typical mission. We discuss the design implications of using a superconducting motor on an aircraft as well as the integration of the electrical propulsion in the aircraft, and the scaling laws derived from physics-based modeling of HTS motors.

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