Parabolic reflector

About: Parabolic reflector is a research topic. Over the lifetime, 3375 publications have been published within this topic receiving 30735 citations. The topic is also known as: paraboloid reflector & paraboloidal reflector.

Experimental Analysis of 2.7 m 2 Scheffler Reflector and Formulation of a Model

Abstract: The performance of 2.7 m 2 Scheffler reflector has been studied. Scheffler Reflector is parabolic dish collector designed to collect energy from sunlight. In this System storage vessel was installed at focus point . Vessel stores 10 ltr of water for the purpose of experimentation. Tests were carried out with this set up for the purpose experimentation. Performance analysis of the reflector revealed that average power and efficiency in terms of water boiling tests to be 550 W and 19%. Maximum temperature of water was observed to be 94 0 C. Ambient temperature was observed to be in between 32 o C and 40 0 C.

Monaural sound-source-direction estimation using the acoustic transfer function of a parabolic reflection board.

Abstract: This paper presents a sound-source-direction estimation method using only a single microphone with a parabolic reflection board. A simple signal-power-based method using a parabolic antenna has been proposed in the radar field. But the signal-power-based method is not effective for finding the direction of a talking person due to the varying power of the uttered speech signals. In this paper, the sound-source-direction estimation method focuses on the acoustic transfer function instead of the signal power. The use of the parabolic reflection board leads to a difference in the acoustic transfer functions of the target direction and the non-target directions, where the parabolic reflector and its associated microphone rotate together and observe the speech at each angle. The acoustic transfer function is estimated from the observed speech using the statistics of clean speech signals. Its effectiveness has been confirmed by monaural sound-source-direction estimation experiments in a room environment.

Nonlinear Structural Analysis Methodology and Dynamics Scaling of Inflatable Parabolic Reflector Antenna Concepts

Abstract: Ultra-light weight and ultra-thin membrane inflatable antenna concepts are fast evolving to become the state-of-the-art antenna concepts for deep-space applications. NASA Langley Research Center has been involved in the structural dynamics research on antenna structures. One of the goals of the research is to develop structural analysis methodology for prediction of the static and dynamic response characteristics of the inflatable antenna concepts. This research is focused on the computational studies to use nonlinear large deformation finite element analysis to characterize the ultra-thin membrane responses of the antennas. Recently, structural analyses have been performed on a few parabolic reflector antennas of varying size and shape, which are referred in the paper as 0.3 meters subscale, 2 meters half-scale, and 4 meters full-scale antenna. The various aspects studied included nonlinear analysis methodology and solution techniques, ways to speed convergence in iterative methods, the sensitivities of responses with respect to structural loads, such as inflation pressure, gravity, and pretension loads in the ground and in-space conditions, and the ultra-thin membrane wrinkling characteristics. Several such intrinsic aspects studied have provided valuable insight into evaluation of structural characteristics of such antennas. While analyzing these structural characteristics, a quick study was also made to assess the applicability of dynamics scaling of the half-scale antenna. This paper presents the details of the nonlinear structural analysis results, and discusses the insight gained from the studies on the various intrinsic aspects of the analysis methodology. The predicted reflector surface characteristics of the three inflatable ultra-thin membrane parabolic reflector antenna concepts are presented as easily observable displacement fringe patterns with associated maximum values, and normal mode shapes and associated frequencies. Wrinkling patterns are presented to show how surface wrinkle progress with increasing tension loads. Antenna reflector surface accuracies were found to be very much dependent on the type and size of the antenna, the reflector surface curvature, reflector membrane supports in terms of spacing of catenaries, as well as the amount of applied load.

Structural Design and Analysis of the Dish Solar Thermal Power System

Abstract: ISH solar thermal power system consists of a support, a concentrator, a receiver, a thermo-electric conversion unit and a sun-tracking control unit. The concentrator including a parabolic reflector, a truss and an elevation- driving circle, reflects the sun's rays into the receiver which is located at the reflector's focus. The concentrated solar energy is absorbed by the receiver and then converted into electricity by the thermo-electric conversion unit. The system works in an exposed environment bearing its own gravity and the wind load. The system's structure should be reasonably designed so that its reliability and stability can be assured. Recently, finite element method has become an effective tool for data analysis and it has been widely used in structural analysis and optimization design. The Visual Structural Analysis Program (VSAP), which is a finite element computation software, has a friendly interface for preprocessing and post-processing of finite elements and has the advantages of easy operation and mastery. Since VSAP is suitable for analyzing special structures, the 10KW dish solar thermal power system is designed and analyzed with VSAP. Furthermore, the problems associated with the concentrator's balancing and system's stability are solved.