Simultaneous velocity and temperature measurements in gaseous flow fields using the VENOM technique

Area of Science:

• Fluid dynamics
• Laser-induced fluorescence spectroscopy
• Thermometry

Background:

• Accurate measurement of flow field properties like velocity and temperature is crucial in various scientific and engineering applications.
• Existing techniques may have limitations in simultaneous measurement or spatial resolution.
• Nitric oxide (NO) is a useful tracer for laser-based diagnostics due to its favorable spectroscopic properties.

Purpose of the Study:

• To demonstrate a novel method for simultaneous velocity and temperature mapping in gaseous flow fields.
• To extend existing two-component velocimetry techniques using vibrationally excited NO.
• To provide spatially resolved maps of both velocity and temperature.

Main Methods:

• Utilized a new nitric oxide planar laser-induced fluorescence (PLIF) based method, termed VENOM (vibrationally excited NO monitoring).
• Generated vibrationally excited NO from the photodissociation of seeded NO(2).
• Acquired two sequential fluorescence images by probing two different rotational states of NO to derive velocity and temperature.

Main Results:

• Successfully demonstrated simultaneous velocity and temperature mapping in gaseous flow fields.
• Obtained good velocity and temperature maps in high-density flow regions.
• Achieved root-mean-square uncertainties of approximately 5% for velocity and 9% for temperature.

Conclusions:

• The VENOM technique provides a viable approach for simultaneous velocity and temperature measurements.
• The method shows promise for characterizing complex flow fields.
• Further refinement may improve accuracy and applicability in lower-density regions.