3 Ways Wireless Combustion Temperature Sensors Help Cameras & Pyrometers

04.05.2021 | Turbine Blades

Many current combustion temperature detection methods detect only the highest temperature experienced during a thermal cycle. Other optical or non-contact solutions will measure ambient air or gas flow temperatures, but not the temperature on the surface of the material itself.

Wireless temperature sensors outfitted with high-accuracy RF sensor technology significantly outperform both IR cameras and other optical pyrometers in extreme environments. While there are many relative advantages to a wireless RF temperature sensor over an IR camera sensor or pyrometer sensor, the three listed below are the primary draw to this precise technology.

1. No Emissivity Errors

Planck’s law of radiation, which correlates temperature with an object’s IR radiation emissions, is a useful bit of science. However, Planck’s law is only optimally valid for “ideal” black body emitters.  The surface condition of the object and the emissivity of the material can introduce error into the calculation.  Corrective adjustments to the formula must precisely account for these variations, and any mistake in identifying the correct value of the material will exacerbate errors in the measurements. 

Emissivity is a dynamic property that depends upon many factors, such as ambient temperatures, the temperature range being measured on the object, the wavelength of the measuring instrument, and more. Shiny or reflective materials, like most metals, also tend to produce unreliable data, as reflective surfaces emit less IR energy (and have less emissivity). It’s possible to use non-reflective coatings or tapes on the surface to be measured, but this is not realistic in the extreme environments and high combustion temperatures of gas turbine engines and other hot metal applications.

An optical pyrometer sensor is typically only able to measure temperature to an accuracy of 1 to 2% of the full-scale range. Wireless combustion temperature sensors with high-temperature RF sensors—such as those manufactured by Sensatek—are accurate to within ±0.71%, avoid the unreliability of optical sensors, and can gather reliable data at incredible thermal levels. 

2. Flexible Housing

A temperature sensor fitted with a wireless type k thermocouple sensor is an easily adaptable solution that’s ideal for measuring combustion temperatures in various parts of extreme heat process technologies (such as kilns, furnaces, and gas turbine engines). If your intention is to collect air temperature, you can package the sensor in tech glass and dangle it in the process.  If a highly accurate surface temperature reading is more valuable, deploy the sensor in a ceramic-derived, wireless RF sensor patch, directly on the substrate to be monitored. The same wireless high-temperature sensor technology can be used in both cases—it’s merely a difference of housing. One goes on the material, and the other is housed in a tech glass tube. A wireless temperature sensor adapts for your application.

3. Numerous Data Points

Tight-focused point measurements have limitations when a more complete picture is needed. Pyrometers are only capable of recording narrow spot combustion temperatures (one for each sensor deployed). It can get expensive and space-prohibitive to instrument a large quantity of pyrometer sensors and increase the number of data points.

IR camera sensors use broader area measurements, but still suffer from emissivity errors and inaccuracy, especially at higher combustion temperatures.

The best solution will be a series of wireless temperature sensors with cost-effective, durable, reliable, and precise RF technology.  A wireless solution makes instrumentation of multiple data points far simpler. One transceiver can collect data from numerous RF wireless temperature sensors for a nuanced and accurate combustion temperature model throughout the heat process and on many individual surfaces.

Looking for further insights into the advantages of wireless RF temperature sensors and RF sensors over optical pyrometers or cameras? Keep an eye on our blog or contact Sensatek directly to discuss the needs of your project, test environment, or engine fleet. We’re happy to answer any questions and help you determine the ideal high-performance solution.

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