Axisymmetric Gregorian Reflector System for a Space-Deployed Inflatable Antenna: Simulations and Measurements

This paper presents the modeling and analysis of a novel vibration suppression device. This reflector system exerts inertial forces, induced by tuned pendular motion, to control translational vibration of a primary system. Tuning of the reflector critically depends on the parameters of the pendula and on the rotational speed at which they are spun about an axis oriented parallel to the undesired motion. Consequently, one of its most appealing attributes is this devices’s ability to be tuned to, and thus actively track, the dominant frequency of disturbance forces. The paper describes how governing equations from an integrated physical model are developed using a bond graph approach and then used to derive relations applicable in design of an inertial reflector system. It is shown how the model supports component selection and tradeoff studies as well as simulation. Experimental results from testing of a laboratory realization of a prototype system are used to verify the design and to compare with simulation of a mathematical model. The results from the laboratory demonstrate the ability of the inertial reflector to control steady and transient vibration, and the favorable results suggest extended investigation for active vibration control situations. In particular, applications in low frequency vibration mitigation are promising.

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Polarization properties of calibration reflector system in the polarization-modulated space laser communication

Optics Communications ◽

10.1016/j.optcom.2018.06.058 ◽

2019 ◽

Vol 430 ◽

pp. 311-317 ◽

Cited By ~ 4

Author(s):

Guoqing Chen ◽

Bin Xue ◽

Jianfeng Yang ◽

Yiyi Zhao ◽

Xingfeng Wang ◽

...

Keyword(s):

Laser Communication ◽

Reflector System

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Experimental investigation of the daily performance of an integrated linear Fresnel reflector system

Solar Energy ◽

10.1016/j.solener.2018.04.019 ◽

2018 ◽

Vol 167 ◽

pp. 220-230 ◽

Cited By ~ 13

Author(s):

Evangelos Bellos ◽

Emmanouil Mathioulakis ◽

Elias Papanicolaou ◽

Vassilis Belessiotis

Keyword(s):

Experimental Investigation ◽

Reflector System ◽

Linear Fresnel Reflector

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Enhanced Infrared Heating of Thermoplastic Composite Sheets for Thermoforming Processes

International Polymer Processing ◽

10.1515/ipp-2020-3923 ◽

2021 ◽

Vol 36 (1) ◽

pp. 35-43

Author(s):

M. Längauer ◽

G. Zitzenbacher ◽

C. Burgstaller ◽

C. Hochenauer

Keyword(s):

Steady State ◽

Composite Materials ◽

Mechanical Performance ◽

Heating Time ◽

Thermoplastic Composite ◽

Infrared Heating ◽

Thermoplastic Composites ◽

Steady State Condition ◽

Reflector System ◽

Heating Station

Abstract Thermoforming of thermoplastic composites attracts increasing attention in the community due to the mechanical performance of these materials and their recyclability. Yet there are still difficulties concerning the uniformity of the heating and overheating of parts prior to forming. The need for higher energy efficiencies opens new opportunities for research in this field. This is why this study presents a novel experimental method to classify the efficiency of infrared heaters in combination with different thermoplastic composite materials. In order to evaluate this, different organic sheets are heated in a laboratory scale heating station until a steady state condition is reached. This station mimics the heating stage of an industrial composite thermoforming device and allows sheets to slide on top of the pre-heated radiator at a known distance. By applying thermodynamic balances, the efficiency of chosen parameters and setups is tested. The tests show that long heating times are required and the efficiency of the heating is low. Furthermore, the efficiency is strongly dependent on the distance of the heater to the sheet, the heater temperature and also the number of heating elements. Yet, using a full reflector system proves to have a huge effect and the heating time can be decreased by almost 50%.

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Arrangement and optimization of mirror field for linear Fresnel reflector system

Optics and Precision Engineering ◽

10.3788/ope.20152301.0078 ◽

2015 ◽

Vol 23 (1) ◽

pp. 78-82

Author(s):

王成龙 WANG Cheng-long ◽

马军 MA Jun ◽

范多旺 FAN Duo-wang

Keyword(s):

Reflector System ◽

Linear Fresnel Reflector

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Geometrical optimization for a photovoltaic installation equipped with flat reflectors based on plane of array estimations

EPJ Photovoltaics ◽

10.1051/epjpv/2019010 ◽

2020 ◽

Vol 11 ◽

pp. 1 ◽

Cited By ~ 1

Author(s):

Christine Abdel Nour ◽

Anne Migan-Dubois ◽

Jordi Badosa ◽

Vincent Bourdin ◽

Claude Marchand ◽

...

Keyword(s):

Power Production ◽

Geometrical Parameters ◽

Estimation Model ◽

Geometrical Characteristics ◽

Pv Module ◽

Geometrical Optimization ◽

Reflector System ◽

The Mean ◽

Experimental Validations ◽

Geographical Characteristics

In order to design, manage and optimize the performance of a photovoltaic (PV) installation and establish a precise power production estimation, irradiance on the plane of array (POA) in relation with the geometrical characteristics of the PV modules installation occupies a high importance. This study focuses on the development of an estimation model of the POA irradiance for a photovoltaic installation equipped with flat reflectors. The model includes solar irradiance components (global, direct and diffuse), geometrical parameters and geographical characteristics of the PV installation. Experimental validations have been performed with measurements taken at the SIRTA Observatory (48.7°N, 2.2°E) in Palaiseau, France, for the period starting from June 2017 to June 2018. Results show mean absolute errors (relative to the mean) of 6% and 7% for an installation without and with planar reflector. Finally, we present several geometrical optimization strategies of the PV-reflector installation relying on two major variables: the reflector's length (LR) compared to the length of the PV module (LPV) and the tilt angle adjustment frequency (monthly, seasonally, fixed) of the system (for both PV and the reflectors). The objective of such optimization is to discuss about a reasonable configuration to achieve a maximum POA irradiance. Results show that the length of the mirrors highly affects the efficiency and performances of the PV-Reflector system and the annual gain increased from 8.5% to 28.7% when going from LR = LPV/2 to LR = 2 × LPV compared to a monthly-optimized installation without mirrors. As for the adjustment frequency, we show that a monthly-varied architecture is the most advantageous option with a 28.2 and 31.6% increasing in annual gain compared to a seasonal varied or fixed ones, respectively.

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