Key result
Constant temperature hot-film anemometry probes tested in water flow revealed unsatisfactory frequency responses in three commercial anemometers at overheat ratios compatible with blood use.
Commercially available hot-film anemometers may have unsatisfactory frequency responses and be subject to calibration errors when used for intra-arterial blood velocity measurements.
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May limit reliability of commercial anemometers for intra-arterial velocity; leaves open need for device validation or redesign.
The application of constant temperature hot-film anemometry to measurement of point blood velocity in arteries is discussed and the importance of certain aspects of design, and of provision of means for detecting flow reversal, is demonstrated. Hot film probes suitable for intra-arterial use have been constructed and tested in regimes of steady and unsteady water flow. At overheat ratios compatible with use in blood three different commercially available anemometers had unsatisfactory frequency responses. Oscillatory calibrations performed in the absence of mean flow were further subject to error due to generation of secondary flows. The likely significance of these various effects in distorting intra-arterial measurements is discussed.
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Seed et al. (1970) studied this question. Constant temperature hot-film anemometry probes was evaluated on Frequency response and oscillatory calibrations. Constant temperature hot-film anemometry probes tested in water flow revealed unsatisfactory frequency responses in three commercial anemometers at overheat ratios compatible with blood use.
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