Hot water corrugated heat transfer tube

Abstract

The present invention relates to a hot water corrugated heat transfer tube that exchanges heat between its interior and exterior. A plurality of projections, each whose height (H1) is in the range of 0.5 mm-1.5 mm, is provided in at least one part of the inner surface of a portion positioned in a section of a corrugated heat transfer tube, where the Reynolds number (Re) of the fluid flowing in the interior of the tube is less than 7,000. The height H1 of the projections is in the range of 0.05-0.15 times the inner diameter D or the height H1 of the projections is in the range of 1-3 times the depth (Hm) of the corrugated grooves. As a result, with a simple structure, the heat transfer performance in the low Reynolds number zone is improved, and the pressure loss inside the tube is small.

Description

TECHNICAL FIELD[0001]The present invention relates to hot water heater technology. More specifically, the present invention relates to a hot water corrugated heat transfer tube in which the Reynolds number Re of a fluid flowing inside the tube is less than 7,000.BACKGROUND ART[0002]Heat exchangers used in air conditioners, hot water heaters, and the like, are provided with a heat transfer tube in which a fluid such as water flows and which exchanges heat due to the temperature differential between the tube interior and exterior. Furthermore, to improve the heat transfer performance of the heat transfer tube, a grooved tube in which grooves are formed on the tube inner surface is used in some cases. In addition, a technology has also been proposed which improves the heat transfer performance by providing projections on the inner surface of the heat transfer tube.[0003]Providing projections inside the heat transfer tube in this manner increases the heat transfer surface area of the he...

AI Technical Summary

Benefits of technology

The present invention provides a hot water corrugated heat transfer tube that improves heat transfer performance in the low Reynolds number section where the flow of the fluid inside the tube is in transition from the laminar flow zone to the turbulent flow zone. The invention achieves this by providing projections on the inner surface of the tube in this section, which reduces friction and pressure loss inside the tube, and minimizes the impact on the heat transfer coefficient. The projections have a height of 0.1-0.15 times the inner diameter of the tube, and are spaced apart from each other to avoid increasing the friction factor. The invention provides a simple solution to improve heat transfer performance in this low Reynolds number section, and ensures high efficiency of the hot water corrugated heat transfer tube.

Problems solved by technology

In addition, efficient heat exchange cannot be expected because the thermal conductivity is also small in the low temperature section in the vicinity of the water inlet.

Further, since the corrugated tube causes a strong turbulence at the boundary of the tube wall, the friction factor inside the tube increases considerably compared to a smooth tube depending on the depth of the corrugated groove, which consequently increases the pressure loss of the flow inside the tube.

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