Aero Engine Turbine Research Institute: Engine Pulsation Test

I. Project Background and Objectives

In June 2024, a research institute under the Aero Engine Turbine Research Institute conducted a pulsation test on a certain aircraft engine using the DE-928U High-Performance Dynamic Signal Test and Analysis System. The test aimed to capture multi-dimensional data, including vibration, pressure, and rotational speed, during engine operation. By analyzing key parameters such as amplitude and order characteristics, the test validated the reliability of the engine design and its compliance with performance indicators.

II. Test System and Solution Design

1. Sensor Arrangement

• Acceleration Sensors: Installed on the engine casing, bearing seats, and pipeline interfaces to monitor radial and axial vibrations.

• Pressure Sensors: Mounted on fuel pipelines, lubricating oil pipelines, and air systems to capture fluid pulsation pressure.

• Speed Sensors: Monitored the engine main shaft speed to provide reference signals for order analysis.

2. Data Acquisition System

• Core Equipment: The DE-928U system supported multi-channel synchronous acquisition with a maximum sampling rate of 200 kS/s and 24-bit resolution.

• Synchronization Accuracy: All channels used hardware synchronization with a time deviation of less than 0.1° (phase error).

• Signal Conditioning: Built-in IEPE excitation source and voltage adaptation module for direct connection to acceleration, pressure, and speed sensors.

3. Test Conditions

• Covered multiple steady-state and transient conditions, including idle, cruise, maximum continuous thrust, and takeoff thrust.

• Each condition was continuously sampled for 3-5 minutes to ensure statistical significance of the data.

III. Test Results and Data Analysis

1. Vibration Characteristics Analysis

• Amplitude Characteristics:

  • Casing vibration acceleration peak ≤ 8.5 g (cruise condition), complying with GJB 4057-2000 military standard limits.

  • Pipeline vibration main frequency concentrated in 200-800 Hz, highly correlated with fluid pulsation frequency.

•      Order Analysis:

  • Rotor passing frequency (1X, 2X orders) was identified using speed signals, with no abnormal high-order harmonics detected.

  • The local resonance frequency of the turbine disk effectively avoided the operating speed, mitigating resonance risks.

2. Pressure Pulsation Analysis

• Fuel Pipeline: Pulsation pressure amplitude ≤ 0.05 MPa, with no high-frequency whistling components observed in the spectrum.

• Lubricating Oil System: Pressure fluctuations were stable, with a maximum fluctuation rate of <3%, meeting lubrication stability requirements.

3. Comprehensive Performance Evaluation

• Correlation analysis between vibration and pressure data indicated that fluid pulsation was one of the main excitation sources for casing vibration.

• No design defects, such as pressure oscillations or structural resonance, were observed under all test conditions.

IV. Core Advantages of the DE-928U System

1. High-Precision Synchronization

• Multi-channel hardware synchronization technology ensured strict time-sequence alignment of vibration, pressure, and speed signals, providing a solid foundation for order analysis.

2. Real-Time Processing Capability

• Built-in real-time FFT, order tracking, and Campbell diagram analysis functions enabled rapid identification of abnormal frequencies during testing.

3. Engineering Design

• The equipment complied with the MIL-STD-810G military standard for vibration  resistance, adapting to the harsh environment of the engine test bed.

• The software supported automatic recognition of TEDS sensors, completing full channel configuration within 30 minutes.

V. Customer Value

• Design Validation: Validated engine dynamic performance through measured data, accelerating the design iteration cycle.

• Fault Early Warning: Established baseline databases for vibration and pressure, providing references for future fault diagnosis.

• Standard Compliance: Generated reports compliant with aviation military standards for direct use in model certification.

VI. Application Expansion

This solution can be further applied to:

•     Gas turbine pulsation characteristic testing;

•     Rocket engine fuel supply system stability evaluation;

•     Industrial compressor pipeline vibration source analysis.