RU2378594C1 - Heat exchanger - Google Patents

Abstract

FIELD: heating systems.

SUBSTANCE: invention refers to heat exchange equipment and is intended for being used as heat exchanger of nuclear power plant operating in variable load mode. In heat exchanger containing the housing with bank of heat exchange tubes, which is located inside it, exchange tubes are fixed in tube sheets, and bank of parallel located corrugated plates in tubular volume, two opposite walls of the housing are corrugated and parallel to bank of plates, and two other ones are flat; each tube is also bent as per plate profile, located between them and equipped outside in straight sections with screw-shaped ribs with changing swirl angle, and inside - with band with swirl direction opposite relative to ribs; at that, in tubular volume there arranged are ejectors which are made in the form of rods fixed in additional tube sheets and located equally spaced.

EFFECT: increasing heat exchange intensity owing to uniformity of temperature field in cross section of heat exchange tube bank, improving operating reliability owing to decrease of relative deformation of tubes at thermal linear expansions.

3 dwg

Description

The invention relates to a heat exchange technique and is intended for use as a heat exchanger (TO) of a nuclear power plant (NPP) operating on a liquid metal coolant in a variable load mode.

A heat exchanger is known that contains a bundle of pipes with transverse partitions, an inner and outer case with openings for entering and leaving a heat carrier and seals, the inner case being made in the form of a spiral wound sheath covering a tube bundle with partitions, and the seals are installed at the coolant outlet, while the outer the housing in the places of installation of seals is made with connectors. [one].

The disadvantage of this technical solution is the low vibration resistance of the design of the heat exchanger and insufficiently intense heat transfer.

A heat exchanger is known that contains tubes with a transverse finning in the form of plates equipped with corrugations arranged at an angle to the flow of the working medium, the corrugations having a rectangular shape with a height equal to 0.18-0.6 widths, and in adjacent plates arranged at an angle. [2].

The disadvantages of this technical solution are insufficiently intensive heat transfer, which leads to an increase in weight and size parameters, low reliability due to the large unevenness of the temperature field in the cross section of the tube bundle, as well as the insecurity of the tube plate from the primary side from thermal shock of the coolant and various relative deformations of adjacent ring rows of heat transfer tubes at temperature extensions, which can lead to grinding of heat transfer tubes.

The technical result of the invention is forced heat transfer to obtain small dimensions of the equipment by increasing the uniformity of the temperature field in the cross section of the tube bundle and reducing the relative deformation of the pipes at temperature elongations.

The specified technical result is achieved by the fact that in the heat exchanger containing the housing with a bundle of heat exchanger tubes mounted inside the tube plates and a packet of parallel-mounted corrugated plates in the annular volume, two opposite walls of the housing are corrugated parallel to the package of plates, and the other two are flat, each pipe is also curved along the profile of the plates, placed between them and provided on the outside in straight sections with screw-shaped ribs with a varying twist angle, and inside with a tape with the opposite direction of the twist with respect to the ribs, while in the annular space equidistant to the pipes displacers are placed in the form of rods fixed in additional tube boards.

The essence of the invention is illustrated by drawings, where:

figure 1 presents a longitudinal section of a heat exchanger;

figure 2 - heat transfer pipe of the heat exchanger;

figure 3 is a section of a transverse section.

The heat exchanger comprises a housing 0, an inlet pipe 1 and a feed water distribution chamber 2, a bundle of heat exchange tubes 3 passing through a package of corrugated plates 4 of the annular volume, a collecting chamber 5 and an outlet pipe 6 of steam, an inlet and an outlet pipe 7, 8 for a liquid metal coolant, an upper and lower additional tube boards 9, 10, an in-line displacer in the form of a tape 11 and screw-shaped ribs 12 located on the outer surface of the zigzag heat transfer tubes 3, as well as displacers in the form of rods 13, reinforced additional tube sheets 9, 10.

The heat exchanger operates as follows.

The thermal exchange process in the design of the heat exchanger is organized according to the countercurrent flow pattern of liquids. The liquid metal coolant through the inlet pipe 7 enters the annulus of the evaporation section of the bundle of heat exchange tubes 3, where the tube plate is protected from direct flow around the coolant with the upper additional tube plate 9, in which the ends of the annular displacers are reinforced in the form of rods 13, then due to some compression of the bore section corrugated plates 4 annular volume provides hydraulic uniformity of distribution along the channels of the package corrugated plates 4 annular volume. Helical ribs 12 of heat transfer tubes 3 with a varying twist angle and an opposite twist angle of the in-line displacer in the form of a tape 11 contribute to the static mixing of the coolant and increase the heat transfer coefficient from the side of the primary circuit. In the mixing chambers formed by sampling the helical ribs 12 at the bends of the heat exchanger tubes 3, the coolant is mixed. From the channels of the package of corrugated plates 4 of the annular volume, the coolant enters the economizer section of the bundle of heat exchange tubes 3 and then leaves through the outlet pipe 8. The lower additional tube plate 10 protects the tube plate from thermal shock of the liquid metal coolant, and also the other ends of the annular displacers are fixed in it rods 13. Feed water through the pipe 1 enters the distribution chamber 2, where the hydraulic uniformity of distribution through the heat exchange tubes 3 is ensured, and then spinning s-tube propellant via a strip 11 with a varying angle of twist turns into steam, entering the collecting chamber 5, from which exits through the outlet 6.

The use of the design of the heat exchanger of the proposed type will significantly improve the heat transfer intensity, uniformity of the temperature field in the cross section of the tube bundle, as well as operational reliability by reducing the relative deformation of the pipes during linear thermal expansion.

Link

1. Naumenko V.V. etc. Heat exchanger. SU. A.c. N 293490, F28D 7/00. Priority - 04.16.63. Publ. Bulletin of inventions N 42. 09/19/1973 - analogue.

2. Averkiev L.A. etc. Heat exchanger. SU. A.c. N 937953, F28D 7/00. Priority - 10/14/80. Publ. Bulletin of inventions N 23. 06.23.82 - prototype.

Claims (1)

A heat exchanger comprising a body with a bundle of heat exchange tubes mounted inside the tube plates and a packet of parallel corrugated plates in the annular volume, characterized in that the two opposite walls of the body are corrugated parallel to the plate pack, and the other two are flat, each pipe is also bent along the profile of the plates, placed between them and provided on the outside in straight sections with screw-shaped ribs with a varying twist angle, and inside with a tape with an opposite relative to the ribs p twist direction, while in the annular volume displacers placed equidistant pipes in the form of bars contained in the additional tube plates.

Images