Development of an airborne integrated phase Doppler interferometer/imaging probe for accurate cloud droplet size distribution measurement

Award Information
Department of Defense
Award Year:
Phase II
Agency Tracking Number:
Solicitation Year:
Solicitation Topic Code:
Solicitation Number:
Small Business Information
150 West Iowa Avenue, Suite 101, Sunnyvale, CA, 94086
Hubzone Owned:
Socially and Economically Disadvantaged:
Woman Owned:
Principal Investigator
 William Bachalo
 (650) 941-4233
Business Contact
 William Bachalo
Title: President
Phone: (650) 941-4233
Research Institution
The Phase II basic effort seeks to develop and test a prototype PDI cloud probe for reliable and accurate measurement of the cloud droplet size distribution from airborne platforms. The key features of this device are high accuracy and precision of dropletsizing, large dynamic range, accurate concentration measurement throughout the entire instrument dynamic range, very low coincidence errors, and large counting volume. The other key features of the instrument are: low cost, low power consumption,compactness, and real-time data monitoring and transmission to ground-based facilities. As an option, we propose to investigate and incorporate a means for discriminating ice-crystals from water droplets. As another option, we have proposed the developmentof an airborne imaging cloud probe to complement the PDI cloud probe. This will permit measurement of both spherical and non-spherical particles. Finally, as a third option, we have proposed to participate actively with the CIRPAS personnel in the flighttesting of these probes. This instrument package represents a significant improvement over past cloud droplet measurement devices, and thereby directly addresses the need for atmospheric instruments/sensors that the Navy has identified in topic N02-61 ofthe FY2002 SBIR solicitation. Clouds are a very important component of the climate system because of their effects on longwave and shortwave radiation, atmospheric heat, moisture, and mass transport, precipitation, and atmospheric chemistry. Clouds andfeedback mechanisms associated with them are widely acknowledged as one of the key uncertainties in understanding climate and future climate prediction. A thorough understanding of clouds is also critical for weather prediction. Quantitative precipitationforecasting is one of the primary focus areas for the US Weather Research Program. The development of a suitable cloud probe will therefore have immense scientific value. Besides clouds, there are wide ranges of applications for an instrument that cancharacterize sprays and droplet fields over a wide size range. The immediate goal of producing a probe for measuring icing clouds and other cloud drop size distributions has a limited but adequate market potential. The obsolescence of the PMS probes hasleft a market opportunity for new probes based on advanced technology. There are also signficant applications requiring an imaging probe for process evaluation and control. For example, in spray drying, the usual light scattering methods fail because thedrops are not transparent or homogeneous. In such cases, an imaging system is the best method to use since it is not affected by the peculiarities of the droplet material. Another area deals with research in fire suppression systems used in commercialbuildings. A system is needed to characterize sprays from fire suppression sprinklers and to help develop these systems. No system exists for these applications whereas the number of spray drying processes including food processing, drug manufacturing,andother industrial processes is enormous. One of the complaints about the PDI method is that it cannot cover the entire drop size range in many sprays and that the larger nonspherical drops can produce significant error.

* information listed above is at the time of submission.

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