Evaporating pipe with narrow-gap steam exhaust opening

Abstract

The invention discloses an evaporating pipe with a narrow-gap steam exhaust opening. T-shaped fins are arranged on the outer surface of the evaporating pipe; a hole is formed between the adjacent fins; spiral channels are formed in the inner surface of a heat transfer pipe. The evaporating pipe is characterized in that a plurality of grooves which extend along the axial direction, the radial direction and the directions which form different included angle together with the axial direction are formed in the outer surface; the intersection of the grooves which extend in different directions is in a shape like a Chinese character 'mi'; a channel which is communicated with the holes outside the pipe is formed in the intersection, i.e., an exhaust opening for steam in the holes is formed; the exhaust opening is in a narrow-gap shape; meanwhile, triangular bulges are formed in the side surfaces of the T-shaped fins, and are protruded on the side surfaces, which are close to the fins as much as possible; the included angles of the triangular bulges and the surfaces of the fins are acute angles. The evaporating pipe with the narrow-gap steam exhaust opening disclosed by the invention works with a low-pressure refrigerant medium, evaporation cores are easy to nucleate and large in number; the bubble detachment frequency is high; the heat exchange effect is good.

Description

Technical field: [0001] The invention discloses an evaporation tube with a slit-shaped steam outlet, which belongs to a high-efficiency heat exchange tube in a flooded evaporator in a refrigeration and air-conditioning system, and is especially suitable for a low-pressure refrigerant, such as R245fa, as a working medium evaporator . Background technique: [0002] Flooded evaporators are an indispensable and important component in commercial refrigeration systems. The performance of the evaporator depends largely on the heat exchange performance of the heat transfer copper tube in the evaporator. In a flooded evaporator, the refrigerant submerges the heat exchange tubes in the evaporator. When the hot fluid flows through the tubes, heat is transferred from the hot fluid to the refrigerant outside the tubes, causing the refrigerant to boil to produce steam. An important way to improve the heat transfer efficiency of the evaporator is to enhance the boiling heat transfer capa...

AI Technical Summary

Problems solved by technology

[0005] Currently widely used T-shaped finned and cavity-structured evaporating tubes and improved evaporating tube structures are suitable for evaporating refrigerants with high working pressure, such as R134a, when boiling, the pressure reaches about 0.3MPa, which has a good effect, but when it is used for low-pressure boiling working fluid, such as R245fa, its boiling pressure is lower than one atmospheric pressure, and its physical properties are quite different from R134a, such as viscosity , surface tension, vapor density, etc. have all changed. In the experiment, it is obvious that the number of bubbles is greatly reduced, the volume of bubbles becomes larger, and the frequency of bubble detachment decreases, which affects the boiling heat transfer coefficient, and the effect is not satisfactory.

Experiments show that the conventional tube type can be suitable for refrigerant R134a, but not suitable for low-pressure refrigerants, such as R245fa

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