Internal spiral heat exchanger

Abstract

The invention discloses an internal spiral heat exchanger. The heat exchanger comprises an upper cover, a base and middle sections connected between the upper cover and the base, each middle section comprises an inner pipe and an outer sleeve, the upper cover and the base are provided with elbows with openings formed in the plate face of the upper cover and the plate face of the base, annular grooves are formed in the plate face of the upper cover and the plate face of the base and surround the opening portions of the elbows, openings in the two ends of the elbows are connected with the inner pipes of the adjacent middle section, interlayers are formed among the outer sleeves, the inner pipes and the annular grooves, communicating cavities are formed in the upper cover and the base to enable the two adjacent interlayers close to the elbows to communicate, the upper cover and the base are formed through metal injection molding, first threaded ribs are arranged on the inner wall face of the inner pipes, the thread pitch L1 of the first threaded ribs meets the condition that L1 is smaller than 0.028 Re*D1, Reynolds number Re=, v is the average flow velocity of fluid on the inner walls of the inner pipes, D1 is the diameter of the inner walls of the inner pipes, and mu is the current kinematic viscosity coefficient of the fluid on the inner walls of the inner pipes. A roundabout heat exchange structure with a long route is formed in the heat exchanger, and sufficient heat exchange between a refrigerant and a secondary refrigerant can be achieved.

Description

technical field [0001] The invention relates to the technical field of heat exchange equipment, and more particularly, to an internal spiral heat exchanger. Background technique [0002] The existing heat exchanger is arranged in the space in a coiled form through the casing formed by the inner pipe and the main pipe. There is a refrigerant in the interlayer space of the casing between the inner pipe and the main pipe, and there is a refrigerant in the inner pipe. For heat exchange with the refrigerant, the inner tube wall is used as the isolation material between the inner tube inner space and the casing interlayer space, and generally a metal with good heat conduction such as copper is used as the heat conduction metal. The inner tube is coiled in parallel with the main tube in the main tube, and the gap between the outer wall of the inner tube and the inner wall of the main tube, that is, the interlayer space, must be kept uniform. Plus turbulent structures. The end of ...

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Problems solved by technology

[0003] On the other hand, when the fluid flows in the pipe, it is easy to form a laminar flow phenomenon on the pipe wall, that is, the fluid particles always move in the direction parallel to the pipe, and the particles do not mix with each other, and the fluid flows on the pipe wall or even in the entire pipe. For example, layers of concentric cylinders are flowing in parallel, obviously, this is not conducive to heat exchange

In order to destroy the laminar flow phenomenon of the fluid and improve the heat transfer performance of the heat exchanger, CN200810231358.X discloses a self-supporting heat exchanger with spiral fins, which has spiral fins welded on each heat exchange tube. The function of supporting the heat exchange tube can also disturb the flow, forcing the fluid to do a spiral flow along the surface of the tube, which increases the disturbance of the fluid and improves the heat transfer coefficient. The fluid generally flows longitudinally in the shell side of the heat exchanger, but its ribs The pitch of the fins is relatively large and the distance between the fins and the tube is the same height. The fins can only be installed on the outer wall of the tube, so that the overall performance is limited by conditions, and its structure and performance need to be further improved and improved.

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