Innovative Commercial and Industrial Heat Transfer Solution Providers
Heat Transfer Solution Mastery
Home / All / The eight major design parameters of finned tube heat exchangers /
Flow velocity parameters: Key factors affecting heat transfer and pressure drop
Flow velocity parameters: Key factors affecting heat transfer and pressure drop
Flow velocity parameters: Key factors affecting heat transfer and pressure drop
Flow velocity is an important factor affecting the performance of heat exchangers. A reasonable flow velocity can improve heat transfer efficiency, but an excessively high flow velocity will lead to an increase in pressure drop, thereby raising the energy consumption of the system. The following are two main aspects of flow velocity parameters:
1. Headwind speed:
The face velocity refers to the speed of air flowing over the surface of the fins. For evaporators, the face velocity is typically 1.5–3 m/s, while for condensers, it is generally 2–3 m/s. The selection of face velocity requires a comprehensive consideration of heat transfer efficiency and pressure drop. A higher face velocity can improve the heat transfer coefficient but also increases air flow resistance, leading to higher fan energy consumption. Therefore, during the design process, it is necessary to perform calculations and experimental verification to determine a reasonable face velocity, achieving an optimal balance between heat transfer performance and energy consumption.
2. Tube-side flow velocity:
The tube-side flow velocity refers to the flow speed of refrigerant or other fluids inside the heat exchange tubes. The magnitude of the tube-side flow velocity directly affects the heat transfer coefficient and pressure drop. Generally, a higher tube-side flow velocity can improve heat transfer efficiency but also leads to an increase in pressure drop. During design, it is necessary to reasonably select the tube-side flow velocity based on the fluid's physical properties (such as density, viscosity, etc.) and heat transfer requirements. For example, for the refrigerant R410a, the typical tube-side flow velocity in an evaporator ranges from 0.5 to 1.5 m/s, while in a condenser, it ranges from 1.0 to 2.0 m/s. By optimizing the tube-side flow velocity, it is possible to ensure heat transfer efficiency while reducing the system's energy consumption.
