The pressure scanning valve is the unsung hero and workhorse of aero-engine test data acquisition systems. 

Through clever multiplexing technology, it delivers high-precision, high-density, and quasi-synchronous 

measurements for hundreds or thousands of engine pressure points with exceptional cost-effectiveness and 

reliability. The data it provides is the direct basis for evaluating engine performance, stability, and reliability, 

and for validating designs, making it an indispensable core tool in aero-engine development.

Overview: The Need for Pressure Scanning Valves

An aero-engine is an extremely complex aerodynamic-thermal-mechanical system. Understanding its performance,

 efficiency, and reliability requires monitoring pressure changes at hundreds or even thousands of points 

simultaneously across components like the inlet, compressor, combustor, turbine, and exhaust nozzle.

Using traditional single-channel pressure sensors presents major challenges:

Prohibitive Cost: Each sensor requires its own signal conditioning and data acquisition channel.

Space Constraints: Limited space on engine test rigs makes installing vast numbers of individual sensors impossible.

Data Synchronization Difficulty: Ensuring perfect microsecond-level synchronization across thousands of 

independent sensors is extremely challenging.

Pressure scanning valves perfectly solve these problems. They are multi-channel (e.g., 32, 48, or 64 channels) 

pressure switching modules. A high-speed solenoid valve sequentially connects each measurement point to a 

single, shared, high-precision reference sensor for measurement. This allows one high-quality sensor to measure 

dozens of points, ensuring high accuracy and excellent synchronization.

Application in Test Phases

Pressure scanning valves are used extensively in almost all aerodynamic performance tests, from component to 

full-engine levels:

Component Testing:

Compressor/Fan Test Rigs: Measure total and static pressure distributions at rotor inlets/outlets, stator vanes, and 

casing walls to map compressor characteristics (surge line, efficiency maps).

Turbine Test Rigs: Measure pressure distributions before and after turbine nozzles and rotor blades to assess 

efficiency and work output.

Combustor Test Rigs: Measure pressure distributions and dynamic pulsations in the combustor head, liner, and 

mixing zones to evaluate stability, efficiency, and cooling effectiveness.

Core Engine & Full-Engine Testing:

Altitude Simulation Testing: The most critical application. Inside an altitude test cell, scanning valves densely 

measure pressure throughout the flow path, from the inlet cowl to the exhaust nozzle, at every cross-section, 

simulating various flight conditions.

Ground Performance Testing: Used on outdoor or indoor test beds to measure key parameters like inlet distortion, 

compressor outlet pressure, and turbine expansion ratio for rating thrust and fuel consumption.

Distortion Testing: Generate pressure/temperature distortion via inlet screens to monitor how distortion patterns 

affect compressor stability margin, validating the engine's tolerance.

Bird/Ice/Water Ingestion Tests: Monitor transient pressure changes inside the engine, especially in the compressor, 

to detect stalls or flameouts.

Airworthiness Certification:
Provide compliance data to authorities (FAA, EASA, CAAC), proving pressure stability under all extreme conditions 

(icing, crosswinds, reverse thrust), heavily relying on scanning valve arrays.

Data Supporting Verification & Results

The massive pressure datasets are central to:

Performance Assessment & Validation:

Thrust & Power Calculation: Precise thrust calculation via nozzle pressure measurements and flow calculations.

Component & Engine Efficiency: Calculating key parameters like compressor pressure ratio, turbine expansion ratio,

 and isentropic efficiency from total pressure/temperature measurements.

Characteristic Map Generation: Each data point on a compressor map relies on hundreds of pressure values 

averaged from a single steady-state scan.

Stability & Operability Assessment:

Surge Boundary Definition: Precisely identifying the surge onset by monitoring violent pressure pulsations.

Distortion Tolerance: Quantifying the impact of inlet distortion on stability margin.

Aerodynamic Design & CFD Validation:

Design Verification: Comparing measured pressure distributions against CFD predictions to validate design tools.

Flow Diagnostics: Using dense measurement points to plot pressure contour maps, analyzing complex flows like 

secondary flows, corner separations, and shock locations to guide design improvements.

Structural Strength & Vibration Assessment:

Pressure Load Mapping: Providing realistic input loads for structural analysis of casings and blades.

Dynamic Pulsations: High-speed scanner modules can capture pressure pulsations linked to combustion instability 

or blade-passing frequencies, key drivers of High-Cycle Fatigue (HCF).

Implementation Details

Installation: Measurement rakes or probes with multiple pressure taps are installed inside the engine flow path. 

These taps are connected to the scanning valve modules via long tubing.

Configuration: Different scanner modules are selected based on pressure range and accuracy requirements. 

Multiple modules are typically networked to a central computer.

Data Acquisition Process:

Calibration: The entire system is calibrated in situ before testing.

Scanning: With the engine at a stable condition, the valve rapidly switches channels, and the sensor measures 

each pressure sequentially.

Quasi-Synchronization: The extremely fast scan rate and stable engine state allow the data to be treated as 

quasi-synchronous for steady-state analysis.

Processing: Raw voltage signals are converted to pressure values, averaged, and used for performance 

calculations and flow mapping.

Challenges & Solutions:

Tubing Effects: Addressed via calibration for steady-state measurements.

Temperature Effects: Mitigated by housing scanners in temperature-controlled enclosures or using software 

compensation.

Vibration: Addressed with robust scanner design and anti-vibration mounting.

Summary

The pressure scanning valve is the fundamental enabling technology for modern aero-engine testing. Its 

multiplexing design provides an unparalleled balance of data density, accuracy, and cost-effectiveness. The 

data it generates is crucial for performance quantification, stability limit definition, design validation, and 

ensuring structural integrity, making it an indispensable tool for developing safer, more efficient, and more 

reliable jet engines.