1. Summary of the Experiment
The study by Adam et al. (2016) investigates non-intrusive flow velocity measurements in a pressurized pipe equipped with an orifice. Orifices are utilized in hydraulic systems to produce pressure drops, which are critical for understanding head losses and flow behavior around such structures. Traditional intrusive methods for measuring flow velocity can disturb the flow field, leading to inaccurate results. To address this issue, the researchers implemented a non-intrusive method using the UVP-DUO, an ultrasonic velocity profiling (UVP) system, along with hydrogen bubbles generated by electrolysis as seeding particles. The primary goal was to evaluate the flow velocities upstream and downstream of the orifice, assess the jet stability, and analyze the pressure drop and power spectra of the flow.
2. UVP-DUO Usage
The UVP-DUO was employed for velocity profile measurements at various cross-sections around the orifice. Specifically, the UVP transducer was placed outside the pipe to avoid disturbing the flow. The following key points describe its usage in the experiment:
- Installation: The UVP transducer, operating at an emitting frequency of 2 MHz, was installed outside the pipe at a 20-degree angle to the vertical. This setup allowed for longitudinal velocity measurements without intruding into the flow field.
- Seeding: Hydrogen bubbles were produced via electrolysis using a device upstream of the orifice to improve signal quality and measurement accuracy. The bubbles served as tracers that scattered the ultrasonic signal, enhancing the detectability of the flow velocities.
- Data Acquisition: Velocity data were collected at a sampling frequency of 22 Hz, with 16,384 samples per measurement. The acquisition focused on one upstream and three downstream cross-sections, capturing the flow dynamics around the orifice.
- Analysis: The velocity profiles were analyzed to determine the distribution and behavior of the flow. Pressure measurements, recorded at 500 Hz using piezo resistive sensors, provided complementary data for assessing the head losses and power spectra of the flow.
3. Advantage of UVP
The use of UVP-DUO in this study offered several advantages over traditional intrusive methods:
- Non-intrusive Measurement: By placing the UVP transducer outside the pipe, the researchers avoided disturbing the flow field, resulting in more accurate and reliable velocity profiles.
- High Spatial and Temporal Resolution: The UVP-DUO provided detailed measurements with high spatial and temporal resolution, essential for capturing the complex flow dynamics around the orifice.
- Real-time Data Acquisition: The system allowed for real-time monitoring of flow velocities, enabling immediate analysis and adjustments during the experiments.
- Versatility: The UVP-DUO's capability to operate at multiple frequencies (ranging from 0.5 MHz to 8 MHz) made it suitable for various flow conditions and measurement requirements.
- Enhanced Signal Quality: The use of hydrogen bubbles as seeding particles significantly improved the quality of the ultrasonic signal, ensuring precise detection of flow velocities even in challenging conditions.
In conclusion, the implementation of the UVP-DUO in this study demonstrated its effectiveness in providing non-intrusive, high-resolution flow velocity measurements in pressurized pipes with orifices. The method not only enhanced the accuracy of the measurements but also offered valuable insights into the flow behavior and head losses associated with orifice structures. These findings underscore the potential of UVP technology in advancing hydraulic research and improving the design and analysis of hydraulic systems.
Read the full scientific paper: Non-intrusive flow velocity measurements in pressurized pipe with orifice
How UVP-DUO Helps to Measure Non-intrusive Flow Velocity in Pressurized Pipes with Orifice