Trajectory Dependent Scattering in Phase Doppler Interferometry: Minimizing and Eliminating Sizing Errors

Sankar, S. V.; Inenaga, Andrew S.; Bachalo, W. D.

doi:10.1007/978-3-662-02885-8_6

Cited by 33 publications

(28 citation statements)

References 2 publications

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“…As the droplet number density increases, the probability of finding more than one particle in the probe volume also increases. Sankar et al [3] have shown that the Doppler signal analyzer (DSA), which is a frequency based processor, is capable of measuring one of several particles present in the probe volume. The DSA cannot, however, account for the other particle(s) present in the probe volume.…”

Section: Description Of the Problem Multiple Particles In The Probe Vmentioning

confidence: 99%

“…Laser diffraction techniques generally require that I/I 0 be greater than 10" 1 in order to avoid errors associated with multiple scattering, while phase Doppler interferometry usually requires that the droplet number densities are less than 10 3 cm" 3 in the size range of 5-300 pi. ^ Of these two diagnostic approaches, the most promising for dense spray applications is phase Doppler interferometry.…”

Section: Introductionmentioning

confidence: 99%

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Phase Doppler Measurements in Dense Sprays

Strakey¹,

Talley²,

Bachalo³

1998

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY) 13-03-19982. REPORT TYPE Paper DATES COVERED (From -To) TITLE AND SUBTITLE Phase Doppler Measurements in Dense Sprays SPONSOR/MONITOR'S ACRONYM (S) SPONSOR/MONITOR'S NUMBER(S) AFRL-PR-ED-TP-1998-060 DISTRIBUTION / AVAILABILITY STATEMENTApproved for public release; distribution unlimited. SUPPLEMENTARY NOTES AbstractMeasurements of droplet size, velocity and volume flux have been made in a dense spray using phase Doppler interferometry. Volume flux measurements have shown significant improvement over conventional phase Doppler techniques through the use of a flow splitter which provided the probe beams and scattered light signals access to the dense core of the spray. Also, the beam waist diameter was made much smaller than the droplets being measured in order to reduce multiple particle occurrences within the probe volume. The volume flux measurements were very encouraging when compared to measurements made with a mechanical patternator.

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Section: Description Of the Problem Multiple Particles In The Probe Vmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Phase Doppler Measurements in Dense Sprays

Strakey¹,

Talley²,

Bachalo³

1998

Self Cite

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“…According to research by Saffman [12] and Grehan et al, [13] the particle trajectory effect arises from the fact that the Gaussian beam illumination on a particle induces the interference between the reflected and the refracted rays on the photodetector. To restrain this effect several methods have been studies, including use of the symmetrical detector arrangement [13,14], optimization of the beam-intersecting angle [19], use of a set of nodal points in the phase-diameter characteristics [20], use of the planar optical layout [21,22], and separation of the refracted ray from the reflected ray by use of polarization [12,14]. Many methods to enhance the performance of the PDA system, both in dynamic range and in accuracy, have been developed [23].…”

Section: Introductionmentioning

confidence: 99%

Characterization of the Spray of the DISI Multi-hole Injector by Means of Phase Doppler Anemometer

Ahmed

Kawahara

Tomita

et al. 2010

JTST

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The spray from a multi-hole injector applied to direct injection spark ignition (DISI) engine was investigated. In order to understand the detailed structure of the transient spray near the nozzle a combined LDA/PDA system was used. PDA system was optimized in order to detect relative smaller droplets. Size-classified technique was used to get deep information about the spray characterizations near nozzle. The experiments were performed at 7 MPa of injection pressure. At early stage of spray the droplet velocity distribution in the centre of the spray showed high value. Smaller droplets under 15 µm showing followability to air flow, while larger droplets over 20 µm will have drag due to momentum decay. Droplets of 15

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“…Unfortunately, a simple reduction in the measurement volume size can cause the phenomena in conflict with the assumption of a uniform illumination. Consequently, the result suffers from error in sizing large particles due to the nonlinearity in the phase/diameter relationship because the beam intensity is practically nonuniform [1][2][3][4][5][6][7][8][9]. Various solutions to minimize the trajectory ambiguity have been proposed for classical geometry [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

The impact of high order refraction on optical microbubble sizing in multiphase flows

Qiu

Hsu

2004

Experiments in Fluids

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The measurements of bubble size and velocity in multiphase flows are important in many researches and industrial applications. It has been found that the high order refraction has great impact on PDA sizing method when the relative refractive index of media is less than one. Although the spatial frequencies of first order refraction and surface reflection become identical at the optimized scattering angle by using previously proposed method, the second order, as well as high order, refractions can not be neglected, because of different spatial frequency and motion direction. The problem has been investigated and a model of phase-size correlation, which also takes the high order refractions into consideration, is introduced to improve the accuracy of bubble sizing. In this study a method based on the recently developed dual mechanisms' scattering model was further developed. Two scattering phases measured by photodetectors are used to calculate the particle size. By utilizing the conversion factor of second order refraction, as well as some high order refractions, the particle diameter can be solved numerically. Hence, the model relaxes the assumption of single scattering mechanism in conventional phase-Doppler anemometry. To demonstrate the capability of the newly developed method, the model was simulated numerically by using Generalized Lorenz Mie Theory (GLMT). The optical parameters such as the measurement volume size, the focus lengths of the sending and receiving lenses, the size and shape of the receiving aperture, the particle size and its trajectory, and the phase conversion factors are used to analyze the performance of the newly developed method. The results of simulation are compared with those based on the conventional method. An optimization method for accurately sizing air-bubble in water has been suggested.

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Trajectory Dependent Scattering in Phase Doppler Interferometry: Minimizing and Eliminating Sizing Errors

Cited by 33 publications

References 2 publications

Phase Doppler Measurements in Dense Sprays

Phase Doppler Measurements in Dense Sprays

Characterization of the Spray of the DISI Multi-hole Injector by Means of Phase Doppler Anemometer

The impact of high order refraction on optical microbubble sizing in multiphase flows

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