SU1815588A1 - Finning for pipes - Google Patents

Description

The present invention relates to the finning of pipes of heat exchangers used for cooling air or other gases containing water vapor.

The purpose of the invention is to increase the efficiency of heat transfer and reduce material consumption. ,

In FIG. 1 shows a fins for pipes, General view; in FIG. 2 - rib for pipes, section: in FIG. 3 - rib, top view: in FIG. 4 - rib.

The fin for pipes consists of ribs 1, made in the form of disks 2. Disks 2 have a central hole 3 for the pipe 4 and are mounted obliquely thereon about its axis O ~ O. The surface of the upstream section C of each disk 2 is made smooth. In the adjacent section D of the disk 2, arcuate channels 5 are made in the form of gutters. The bulges K of these channels 5 protrude on the surface of the section D of the disk 2, inclined at an acute angle a to the axis of the pipe О-О.

Since the disks 2 of the proposed fins are placed on the pipe at an angle to its axis

O-O, and therefore to the direction of air movement, the boundary layer will develop along the surfaces of the disks 2 under the influence of a pressure gradient.

When an air stream flows around the surface of the disk 2 with protruding convexes K of the channels 5, a negative pressure gradient arises, causing a pressure drop. When pressure drops on the streamlined surface, the boundary layer remains laminar. Air in the boundary layer, moving in the near-wall region, reaches channels 5. The bulges K of channels 5 act as wall turbulators, with the help of which the greatest effect in the intensification of heat transfer can be achieved. The grooves of the channels 5 cause separation of the boundary layer, and therefore eliminate substantial thermal resistance.

On the opposite side of the disk, the pressure gradient is positive. With a positive pressure gradient in section C, a laminar boundary layer arises, which quickly transforms into a turbulent one. In section D of the same surface of di1815588 A1 ska, due to the increase in pressure, the turbulent boundary layer breaks off.

In a heat exchanger cooling moist air, condensation of water vapor occurs on the heat exchange surface. The arcuate channels 5, made on the disk 2 in the form of gutters, are filled with liquid, which is contracted under the action of capillary forces from the surface of the rib. On the opposite side of the rib, the liquid collects under the action of surface forces in the grooves formed by the rib and the convexity of the K channels 5. The arcuate shape of the channels 5 increases the length of the grooves on the rib, which increases the efficiency of the condensate suction from the working surface of the heat exchange. Channels 5 also allow for the organization of condensate drainage, so the downstream pipes of the heat exchanger will not be filled with liquid condensed on the upper pipes.

Timely removal of condensate and intensification of heat transfer with the help of arcuate channels can reduce the area of the heat exchange surface of the apparatus, and, consequently, reduce material consumption.

The technical and economic efficiency of the proposed finning for pipes in comparison with the prototype is to increase the efficiency of heat transfer by 12-14% and reduce material consumption by 10%.

Claims (1)

Claim. The fins for pipes made in the form of round disks with a central hole 15 for the pipe, located obliquely relative to the axis of the vertical pipe, and the surface of the upstream section of each disk is smooth, characterized in that, in order to increase the efficiency of the heat exchange process and reduce material consumption, section of each disk is made of arcuate channels in the form of gutters. ABOUT Fig a