Empirical modelling and simulation of transmission loss between wireless sensor nodes in gas turbine engines

Transmission loss measurements between a grid of hypothetical WSN node locations on the surface of a gas turbine engine are reported for eight frequencies at 1 GHz intervals in the frequency range 3.0 to 11.0 GHz. An empirical transmission loss model is derived from the measurements. The model is incorporated into an existing system channel model implemented using Simulink as part of a wider project concerning the development of WSNs for the testing and condition monitoring of gas turbine engines

Wireless Communication Networks for Gas Turbine Engine Testing

A new trend in the field of Aeronautical Engine Health Monitoring is the implementation of wireless sensor networks (WSNs) for data acquisition and condition monitoring to partially replace heavy and complex wiring harnesses, which limit the versatility of the monitoring process as well as creating practical deployment issues. Using wireless technologies instead of fixed wiring will fuel opportunities for reduced cabling, faster sensor and network deployment, increased data acquisition flexibility and reduced cable maintenance costs. However, embedding wireless technology into an aero engine (even in the ground testing application considered here) presents some very significant challenges, e.g. a harsh environment with a complex RF transmission environment, high sensor density and high data-rate. In this paper we discuss the results of the Wireless Data Acquisition in Gas Turbine Engine Testing (WIDAGATE) project, which aimed to design and simulate such a network to estimate network performance and de-risk the wireless techniques before the deployment

2012 PWST Workshop Summary

No abstract availabl

Wireless Sensor Needs Defined by SBIR Topics

This slide presentation reviews the needs for wireless sensor technology from various U.S. government agencies as exhibited by an analysis of Small Business Innovation Research (SBIR) solicitations. It would appear that a multi-agency group looking at overlapping wireless sensor needs and technology projects is desired. Included in this presentation is a review of the NASA SBIR process, and an examination of some of the SBIR projects from NASA, and other agencies that involve wireless sensor developmen

Passive Wireless Temperature Sensing in Extreme Harsh Environments

As the technology in the elds of aerospace and the US power generation industry advances, there is a critical need for new extreme high temperature sensing / monitoring technologies to replace the current out-of-date sensing systems. As the operating temperatures of these jet and turbine engines continue to rise over 1000 C, it is vitally important to monitor the extreme high temperatures in these engines for system health monitoring and to achieve greater engine eciencies. We propose a new passive wireless temperature sensor capable of sensing these extreme high temperatures. The sensor uses an LC resonance circuit to measure the temperature through passive wireless communications. A new novel method of capturing large quantities of frequency information from the sensor is proposed and allows for advanced signal processing methods form other applications areas like wireless communi- cations, radar, and radio astronomy to be implemented. The passive wireless LC resonance high temperature sensor was successfully able to sense temperatures up to 700 C

Wireless Sensor Applications in Extreme Aeronautical Environments

NASA aeronautical programs require rigorous ground and flight testing. Many of the testing environments can be extremely harsh. These environments include cryogenic temperatures and high temperatures (greater than 1500 C). Temperature, pressure, vibration, ionizing radiation, and chemical exposure may all be part of the harsh environment found in testing. This paper presents a survey of research opportunities for universities and industry to develop new wireless sensors that address anticipated structural health monitoring (SHM) and testing needs for aeronautical vehicles. Potential applications of passive wireless sensors for ground testing and high altitude aircraft operations are presented. Some of the challenges and issues of the technology are also presented

Conjoined piezoelectric harvesters and carbon supercapacitors for powering intelligent wireless sensors

To achieve total freedom of location for intelligent wireless sensors (IWS), these need to be autonomous. To achivethis today there is a need of broadband piezoelectric energy harvesting and a long-lasting energy. The Harvester needto be able to provide sufficient amount of energy for the intelligent wireless sensor to perform its task. The energystorage needs to fulfill the requirement of a large number of charge discharge cycles and contain sufficient power forthe intelligent wireless sensor.The biggest issue with piezoelectric energy harvesting today is the bandwidth limitation. Solutions today to achievelarger bandwidth make a tradeoff where the output is decreased. The biggest issue for energy storage today is thelimitation of energy density for supercapacitors and the lack of sufficient life cycles for batteries.This thesis aims to realize piezoelectric energy harvesters with broad bandwidth and maintained power output.Moreover, for energy storage in the form of supercapacitors realize an electrode material that has a high effectivesurface area, good conductivity not dependent on a conductive agent and can be used without a binder. This thesiscover background and history of the two fields, discussion of technologies used and presents solutions for piezoelectricenergy harvesting and carbon based supercapacitor storage.A Backfolded piezoelectric harvester was made of two conjoined piezoelectric cantilevers, one placed on top of abottom cantilever. By the backfolded design this thesis show that by utilizing the extended stress distribution of thebottom cantilever a maintained power output is achieved for both output peaks. By introducing asymmetry where thetop cantilever have 80% length compared with the bottom cantilever the bandwidth was increased. An effectivebandwidth of 70 Hz with voltage output above 2,75 V for 1 g is achieved.To achieve further enhanced bandwidth a piezoelectric energy harvester with selftuning was designed. Theselftuning was achieved by a sliding mass on a beam, which is conjoined, to two piezoelectric cantilevers in abackfolded structure. By introducing length asymmetry, the effective bandwidth was enhanced to 38 Hz with a poweroutput above 15 mW, for 1 g, which is sufficient for an intelligent wireless sensor to start up and transmit data.To utilize the positive output effect from conjoined cantielvers a micro harvester was fabricated. The design wasbased on the same principle as for the backfolded, but for fabrication reasons the design was made in one plane. Theharvester contain two outer cantilevers conjoined to a backfolded middle cantilever. Due to fabrication difficulties,only a mechanical characterization of the harvester was possible. The result from the characterization looks promisingfrom a harvesting point of view, by showing a clear peak that seems to be somewhat broadband.Energy storage for an autonomous wireless intelligent sensor (IWS) needs to be able to charge and discharge duringthe lifetime of the IWS. Therefor the choice fell on supercapacitors instead of batteries. Over time the supercapacitordue to its superior amount of charge and discharge cycles, outperform a battery when energy density is compared.Increasing the energy density for supercapacitors gives the advantage to prolong the providing of power to theIWS. One such electrode material is conjoined carbon nanofibers and carbon nanotubes. The material is not dependenton conductive agents or binders. The effective surface area can be expanded through a denser structure of CNF, wheremore CNT can grow. In combination with activation, which will yield more micropores, hence an increasedcapacitance for the presented synthesized material yielded 91 F/g with an effective surface area of 131 m2.There is many challenges to power an IWS on a gasturbine. This thesis cover challenges like vibrations on cables,placement issues and the charge of a supercapacitor by harvested energy that comes in small chunks. Solutions forthese challenges are offered.The presented work in this thesis shows how the bandwidth for piezoelectric energy harvesters can be broader byasymmetric implementation of conjoined resonators. In addition, the advantages of conjoined carbon electrodematerials to be implemented as electrode material in supercapacitors. Both harvester and storage are intended to beused as energy sources for intelligent wireless sensors