Thermal Anemometry and Hot wire Anemometer I — Lesson 3

This lesson covers the concept of flow measurements and thermal anemometry in fluid mechanics. It begins with a brief recap of flow measurements, including volumetric or mass flow rate, point velocity measurements, and the determination of the flow stream line. The lesson then delves into thermal anemometry, a technique used to measure flow velocity by measuring heat transfer. The lesson explains the use of hot wire and hot film methods in thermal anemometry, detailing their structure, operational principles, and limitations. It also discusses how to measure heat transfer and how it relates to flow velocity. The lesson concludes with a discussion on the modification of probe design to measure different velocity components.

Video Highlights

01:47 - Explanation of hot wire and hot film methods
15:19 - Limitations of general purpose probes
25:25 - Explanation of hot wire response and heat transfer/a>
35:20 - Discussion on measuring different velocity components

Key Takeaways

- Flow measurements in fluid mechanics include volumetric or mass flow rate, point velocity measurements, and the determination of the flow stream line.
- Thermal anemometry is a technique used to measure flow velocity by measuring heat transfer, using either hot wire or hot film methods.
- The hot wire and hot film elements are electrically heated and placed in a flow field, and the heat transfer is measured to determine the flow velocity.
- General purpose probes are not suitable for measuring flow velocity close to solid boundaries, necessitating the use of boundary layer probes.
- The design of probes can be modified to measure different velocity components.