Applications that require the measurement of the spatially averaged velocity over a given area segment can be addressed by the thermal transient anemometer (TTA). The operating principle can be characterized as follows: (i) elevate the temperature of the multi-X patterned sensor—that appropriately samples the area of interest—to an initial overheat condition, (ii) allow the sensor to cool by the heat transfer of the passing fluid (plus end conduction effects), (iii) execute a calibration such that the exponential decay of the sensor resistance can be characterized by the time constant, τ, and (iv) infer the spatially averaged velocity ⟨U⟩—or the spatially averaged density–velocity product ⟨ρU⟩—from the relationship Note that A″, B″, n are defined by the calibration data. A description of the enabling electronics, demonstration measurements in a calibration air stream and the post-processing strategy to account for ambient temperature changes between calibration and test data are presented in order to characterize this instrument.

The thermal transient anemometer is a measurement device to obtain area average values of temperature and velocity. Its development was motivated by HVAC (heating, ventilation and air conditioning) and cooling-air circuit automotive development efforts. Analytic considerations, which address utilizing room temperature velocity calibration data in applications with elevated ambient temperatures, have been evaluated and supported by direct experiments. Free stream turbulence levels, as expected for the intended applications, have also been shown to have no effect on the velocity calibrations.

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The operating principle, and proof-of-concept data, for a physical device (the mass loading monitor) to alert plant operators when airborne dust approaches the minimum explosive concentration (MEC) level are presented. The MEC, stated as g m−3, is dependent upon the material and environmental factors. Values as low as 30 g m−3 must be evaluated. The measurement strategy, a temporal integration of the piston face pressure as the air-plus-dust charge is impulsively expelled from a cylinder compared with the same integral for an air-only sample, is shown to yield the mass loading (xx g m−3) of the airborne dust. This measurement strategy is demonstrated using a dedicated test apparatus. This demonstration establishes the proof of concept.