System for determining an ensemble characteristic of a particle-laden flow

#This application is a non-provisional of U.S. Provisional Application Ser. No. 62/685,104, filed Jun. 14, 2018, entitled “ADVANCED PROCESSING FOR SPRAY FLUX MEASUREMENTS USING PHASE-DOPPLER INTERFEROMETRY,” the contents of which are expressly incorporated herein by reference in their entirety, including any references therein.

#The present disclosure generally relates to systems and methods for measuring sprays based upon individual measurements taken of individual droplets and thereafter performing analysis on an ensemble of such individual measurements of the droplets that pass through a measurement region of a measurement system. More particularly, the present disclosure relates to a measurement system where at least a droplet dimension (e.g. diameter) is determined for individual droplets passing through a measurement volume.

#Spray flux is a spatially-dependent vector characteristic of a flow field representing the net time-averaged or ensemble-averaged volumetric transport of the liquid phase per unit area per unit time. Spray flux may be expressed in terms of ccliquid/(cm2 s).

#While the appended claims set forth the features of the present invention with particularity, the invention and its advantages are best understood from the following detailed description taken in conjunction with the accompanying drawings, of which:

#FIG. 1 is a schematic block diagram of an exemplary system arrangement for carrying out an illustrative example of the invention

#FIG. 2 is a chart relating effective beam diameter (B*) as a function of droplet diameter (d*);

#In the present disclosure, a robust system and method are described to determine spray flux results using phase-Doppler data of spray droplets having arbitrary droplet velocities and arbitrary measurement volume geometries. The system and method described herein are adapted not only for measurements in a laboratory environment, but also in real world spray applications, to provide a live, real-time measurement of various spray parameters using phase-Doppler sensors. For example, in an agricultural application where a plurality of spray nozzles is arranged along a boom, a single sensor may be used to accurately and discretely monitor and measure spray parameters of different spray nozzles on the boom during operation, to provide a live feedback to a controller operating the nozzles. Moreover, the method described herein is applicable to any flux-based particle characterization instrument or technique for which the effective sampling area is dependent upon the trajectories of the measured particles as well as at least one additional characteristic (mark) of the measured particles.

#An aspect of determining spray flux is determining an “effective sampling area” or “effective area” of a measurement volume of the phase-Doppler interferometry system. The effective sampling area is dependent upon one or more marks of the particles individually or as an ensemble. In one embodiment, the system incorporates a method that includes establishing a model representation of a measurement volume as a function of a particle trajectory and at least one other mark(s) such as droplet size. The method further includes determining an effective sampling area according to a projected area of the measurement volume (e.g. a measurement volume defined by two intersecting beams of a phase-Doppler interferometry system as sensed through an aperture in the optical receiver) along the particle trajectory.

#Another aspect of accurate determination of a spray flux is performing a validation process, and adjusting the “effective sampling area” for an ensemble of droplet data points used to calculate the spray flux, using a predicted distribution of one or more marks for random transits across the measurement volume created as a function of the particle trajectory and at least one other mark(s). Thus, in accordance with a further aspect of the illustrative example, the method for determining spray flux includes determining a fraction of the effective sampling area that would not result in valid measurements from the calculations or distribution predictions. An area fraction that results in invalid measurements is removed from the effective sampling area within the measurement volume. Furthermore, limits to an acceptable range of results of mathematical expressions involving one or more marks are applied to measurements within the valid fraction of the measurement volume. Thereafter, the effective sampling area to be rejected due to the limits applied is removed. This can be determined from an evaluation of the limits applied to the predicted distributions. The method steps are applied for all particles or ensembles of particles as appropriate, and ensemble statistics (e.g. spray flux) are determined for the system using the calculated effective sampling areas.