Inner grooved tube

Inner Grooved Tube：

An Inner Grooved Tube, also known as a dry steam tube, internal rib tube, or internal fin tube, features one or more spiral grooves on the inner wall. These grooves have a rectangular cross-section and are designed to enhance heat transfer efficiency. Primarily used in central air conditioners, they are integral to the performance of dry evaporators.

Working Principle of Inner Grooved Tube

The Inner Grooved Tube is engineered to optimize the heat transfer process during the phase change from liquid to vapor. As the working fluid heats up and evaporates inside the tube, it transitions from nucleate boiling to film boiling when the surface is not quickly replenished with liquid. This leads to a reduction in the heat transfer coefficient and a rise in tube wall temperature, which can damage the heating surface.

To prevent film boiling deterioration, the design ensures that water on the tube's inner wall is replenished effectively. This is achieved by utilizing centrifugal force, which directs water droplets from the central steam flow to the tube wall. The spirally rising internal threads play a crucial role in this process by rotating the fluid and allowing water droplets to reach and maintain a water film on the wall. Additionally, the rectangular grooves help retain this water film, preventing immediate evaporation and enhancing heat transfer.

Application of Inner Grooved Tube

Inner Grooved Tubes are widely used in central air conditioning systems, specifically in dry evaporators where they provide efficient heat exchange. The exterior of the tube cools down as the refrigerant inside evaporates and expands. These tubes are also found in domestic and commercial air-conditioning heat exchangers and high-efficiency heat exchangers.

The design of the inner grooved tube significantly increases the internal surface area per unit length—by 1.5 to 2 times compared to smooth copper tubes. This results in a heat transfer coefficient that is 1.5 to 2.4 times greater than that of comparable smooth copper tubes, with only a slight increase in flow resistance (3-5%). Such improvements enable energy savings of 20-35% and allow for a reduction in the weight of refrigeration air conditioners by 10-25%.

This introduction provides a detailed yet concise overview of the Inner Grooved Tube's functions and applications, enhancing its accessibility and discoverability online.