Application Note:
Heat Flux Estimates for Glass Bottle Molding

Rapid variations in ultrasonic time-of-flight have been used to estimate heat flux in a glass bottle molding.  This application demonstrates the rapid response and remote sensing characteristics for the ultrasonic method.  The measurement configuration is illustrated in Figure 1a where and ultrasonic sensor is attached to a metal rail while monitoring the passage of molten “blobs” of glass as the pass from the furnace to the bottling mold.  Figure 1b shows the “raw” ultrasonic time-of-flight, ToF data resulting from the passage of each 1100oC “blob” sliding by an ultrasonic probe attached to the exterior surface of the rail.  These measurements were made asynchronously and the dwell time in front of the sensor probe aperture is ~4 milliseconds.  The probe is located approximately 12 millimeters from the interface between the hot “puck” and the inner rail surface.    Ultrasonic data indicate a peak heat flux of ~8 MW/m2.    For this measurement, the response time is limited by the pulse repetition rate of the ultrasonic probe which was 70 Hz.

Sensor Configuration
ToF Data
Figure 1 a) Glass “Blob”/senor configuration; b) Ultrasonic Time-of-Flight data for passage of 10 “Blobs”