Fluid flow meter using thermal tracers
AssigneeNederlandse Organisatie voor toegepast-natuurwetenschappelijk onderzoek TNO
InventorsArno Willem Frederik Volker, Leon Ferdinand Gerard Geers, Huibert Blokland, Theodoor Peter Martijn Hunter
Life of this patent
Estimating the term…
Abstract
Fluid flows through a conduit. To measure flow speed the fluid is heated at a heating location in the conduit with a time-dependent heating strength. A speed of sound in fluid flowing in the conduit is measured at a plurality of sensing locations downstream from said heating location. The flow speed of the fluid is determined from a delay with which the time dependence is detected in the sound speeds measured at said sensing locations. In an embodiment a frequency of the variation of heating strength that is used to determine the flow speed is selected automatically dependent on the flow speed and/or other circumstances.
Claims10
A fluid flow meter, comprising
- a conduit;
- a heater configured to heat fluid at a heating location in the conduit;
- sensors configured to remotely measure a local property of the fluid that is dependent on local temperature of the fluid in fluid flowing in the conduit at a plurality of sensing locations downstream from said heating location;
- a data processing circuit configured
- to cause the heater to heat the fluid using a plurality of heating patterns of respective different frequency simultaneously,
- to obtain measurements of said property from the sensors during a predetermined time interval,
- to compute phase and amplitude values of frequency components of variations of the property in said time interval for the respective different frequencies iteratively, with successive iterations to estimate corrections of the compute phase and amplitude values from measurements of the property from which estimates of the components obtained from a previous iteration have been subtracted, and
- to determine flow speed from differences between the phase values computed for a selected one of the frequencies or a selected range of the frequencies for respective ones of the sensing locations.
A method of performing a measurement of fluid flow, the method comprising
- applying a fluid flow to a conduit;
- heating the fluid at a heating location in the conduit with a time-dependent heating strength using a plurality of heating patterns of respective different frequency simultaneously;
- remotely measuring measure a local property of the fluid that is dependent on local temperature of the fluid in fluid flowing in the conduit at a plurality of sensing locations downstream from said heating location;
- computing phase and amplitude values of frequency components of variations of the property in a time interval for the respective different frequencies iteratively, with successive iterations to estimate corrections of the compute phase and amplitude values from measurements of the property from which estimates of the components obtained from a previous iteration have been subtracted, and
- determining flow speed from differences between the phase values computed for a selected one of the frequencies or a selected range of the frequencies for respective ones of the sensing locations.
A computer program product for performing a measurement of fluid flow, the computer program product comprising instructions, which, when executed by a programmable computer cause the computer to
- to cause the heater to heat the fluid using a plurality of heating patterns of respective different frequency simultaneously,
- to obtain measurements of a local property of the fluid that is dependent on local temperature of the fluid in fluid flowing in the conduit at a plurality of sensing locations downstream from said heating location during a predetermined time interval,
- to compute phase and amplitude values of frequency components of variations of the property in said time interval for the respective different frequencies iteratively, with successive iterations to estimate corrections of the compute phase and amplitude values from measurements of the property from which estimates of the components obtained from a previous iteration have been subtracted, and
- to determine flow speed from differences between the phase values computed for a selected one of the frequencies or a selected range of the frequencies for respective ones of the sensing locations.
A method of performing a measurement of fluid flow, the method comprising
- applying a fluid flow to a conduit with a flow speed in a range between 10−4 meter per second and 10−2 meter per second;
- heating the fluid at a heating location in the conduit with a time-dependent heating strength that comprises a heating pattern that sinusoidally depends on time;
- measuring a local property of the fluid that is dependent on local temperature of the fluid in fluid flowing in the conduit at a plurality of sensing locations downstream from said heating location;
- determining flow speed of the fluid from a delay with which the time dependence of the heating strength of heating is detected in the sound speeds measured at said sensing locations.
Dependencies are inferred from the claim text.