Artium PDI-X00MD Modular Phase Doppler Interferometer System

Overview

The Artium PDI-X00MD Modular Phase Doppler Interferometer is a high-precision, laser-based optical diagnostic system engineered for non-intrusive, simultaneous measurement of droplet/particle size distribution, three-dimensional velocity vector components, and transit time statistics in turbulent sprays, atomized flows, and dispersed-phase environments. Unlike conventional LDV (Laser Doppler Velocimetry) systems that infer size from intensity assumptions, the PDI-X00MD implements true phase Doppler particle analysis (PDPA) — a first-principles technique grounded in interference fringe spacing and phase shift between two or more scattered beams. By detecting the relative phase difference of light scattered at multiple angles from a single spherical particle crossing the measurement volume, the system directly computes diameter without reliance on Mie scattering calibration curves or assumed refractive index values. This physics-based approach ensures traceable dimensional accuracy to within ±0.5 µm across its full operational range (0.5–2000 µm), independent of local laser irradiance, beam alignment drift, or optical path attenuation — a critical advantage in long-duration wind tunnel campaigns or harsh aerospace test environments.

Key Features

• Modular optical architecture supporting 1D, 2D, and 3D velocity vector acquisition via configurable transmitter/receiver head arrangements
• Integrated solid-state lasers eliminating fiber-coupled instability and modal noise common in legacy LDV/PDPA platforms
• Automated optical alignment and real-time sampling volume optimization based on local particle concentration and flow topology
• Advanced Signal Analyzer (ASA) — a patented analog-digital hybrid processor implementing adaptive heterodyne mixing, phase-domain pulse detection, and self-tuning sampling frequency control
• High-fidelity signal conditioning chain: PMT preamplification → programmable high-pass filtering → analog gain staging → low-noise digitization at up to 320 MHz effective sampling rate
• Real-time event packetization: each Doppler burst is timestamped, tagged with transit time, velocity component, phase-derived diameter, and optional external trigger synchronization (e.g., shaft encoder, combustion event marker)
• Fully remote operation via TCP/IP client-server framework; supports concurrent multi-user access, role-based permissions, and encrypted session management

Sample Compatibility & Compliance

The PDI-X00MD accommodates a broad spectrum of dispersed-phase media including water/glycerol sprays, fuel atomization clouds, pharmaceutical inhaler plumes, cloud microphysics simulants, and abrasive-laden pneumatic transport streams. Its robust optical design enables stable operation under vibration, thermal cycling, and ambient particulate loading — validated in NASA GRC cryogenic wind tunnels and ONR marine spray characterization facilities. The system complies with ISO 9001:2015 quality management protocols for instrument manufacturing and is architected to support regulatory-compliant data integrity workflows. When deployed with validated software configurations and electronic signature modules, it meets foundational requirements of FDA 21 CFR Part 11 for audit trails, data immutability, and user authentication — making it suitable for GLP and early-phase GMP process development studies involving aerosol delivery device qualification.

Software & Data Management

The native acquisition and analysis suite operates natively on Windows XP/2000 and Linux 2.4 kernel environments, leveraging a modular client-server architecture that decouples hardware control from post-processing. Core capabilities include automated parameter initialization, real-time statistical summarization (mean, RMS, skewness, kurtosis), cross-correlation mapping between velocity and diameter, and volumetric flux integration over user-defined spatial domains. MATLAB-compatible APIs enable direct script-driven experiment orchestration and custom algorithm injection into the signal processing pipeline. All raw event data are stored in hierarchical binary formats with embedded metadata (laser wavelength, focal length, scattering angle geometry, calibration timestamps). Export options include IEEE-compliant .mat files, tab-delimited ASCII, and Excel-ready CSV — preserving full precision of phase-derived diameters and sub-microsecond transit times. Long-duration acquisitions (>72 h) are segmented automatically into time-stamped archives to prevent file corruption and simplify batch analysis.

Applications

• Quantitative validation of CFD multiphase models for gas turbine fuel injectors and rocket engine preburners
• Regulatory-grade performance testing of metered-dose inhalers (MDIs) and dry powder inhalers (DPIs) per USP & Ph. Eur. guidelines
• Cloud microphysics research: droplet growth kinetics, collision-coalescence efficiency, and ice nucleation onset thresholds
• Aerospace icing mitigation: real-time monitoring of supercooled droplet spectra impacting aircraft wings and engine inlets
• Industrial spray drying optimization: residence time distribution mapping, evaporation rate profiling, and agglomeration onset detection
• Biomedical aerosol delivery: capsule dispersion dynamics in nasal airflow phantoms and pulmonary deposition modeling

FAQ

Does the PDI-X00MD require calibration against reference particles?
No. Phase-derived diameter measurement is fundamentally absolute, relying only on laser wavelength and geometric scattering angle — both traceable to SI standards. Calibration artifacts from refractive index assumptions or Mie inversion errors are eliminated.
Can the system resolve bidirectional flow in highly turbulent regions?
Yes. With configurable dual- or triple-scatterer receiver heads and sign-sensitive Doppler frequency demodulation, the PDI-X00MD delivers unambiguous velocity directionality even at reversal points in recirculation zones.
Is the ASA processor compatible with third-party signal analysis tools?
Yes. Raw time-series waveforms and fully parsed event packets are accessible via documented memory-mapped I/O and TCP socket interfaces, enabling integration with LabVIEW, Python (NumPy/SciPy), or custom FPGA-accelerated analytics pipelines.
How does the system handle high-concentration sprays where multiple particles occupy the probe volume simultaneously?
The ASA employs adaptive pulse-pair discrimination and transient amplitude gating to isolate individual particle crossings. At concentrations exceeding 10⁴ particles/cm³, optional spatial filtering or reduced measurement volume configuration maintains event fidelity.
What level of technical support and documentation is provided with the system?
Artium supplies comprehensive NIST-traceable calibration certificates, ISO/IEC 17025-aligned uncertainty budgets, application-specific SOP templates, and on-site installation/commissioning by certified field engineers — including flow-field mapping protocol development and CFD boundary condition extraction guidance.