RU2384802C1 - Heat exchanger - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: invention refers to heat engineering and can be used as heat exchanger of nuclear power plant operating in variable load conditions. In heat exchanger containing a bundle of heat exchange zigzag-shaped tubes with external finning in straight sections, which is installed in the housing, spacers arranged between tubes of the bundle so that mixing chambers are formed in the bending area of the latter, the spacers have thickenings in straight tube sections and grooves evenly spaced relative to them so that an individual channel is formed around each tube, which interconnects mixing chambers to each other.

EFFECT: providing forced heat exchange for obtaining small overall dimensions of equipment owing to increasing uniform temperature field in cross section of tube bundle, and decreasing relative tube deformation at thermal elongations.

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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 shell with openings for entering and exiting the coolant, and seals, the inner shell being made in the form of a spiral wound shell covering the bundle of tubes with bulkheads, and the seals are installed at the coolant outlet, the outer casing in the places of installation of seals is made with connectors [1].

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

Known shell-and-tube heat exchanger with corrugated sheets in the annular space to direct the flow of coolant, and the sheets are made with cutouts on the corrugation vertices equal to half the pipe section and adjacent their edges to the surface of the corresponding pipe [2].

The disadvantage of this technical solution is insufficient heat exchange, which leads to an increase in weight and size parameters, low reliability during the process, due to the fact that in the area of contact of the edges of the cut with the pipe there is a high probability of grinding of the pipes due to the uneven temperature field in the cross section of the tube bundle, as well as the insecurity of the tube plate from the side of the primary circuit from thermal shock of the coolant.

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 a bundle of heat-exchanging tubes of a zigzag shape with external screw fins in straight sections, spacer plates placed between the tubes of the bundle with the formation of mixing chambers in the bending zone of the latter, according to the invention, the plates have thickenings on straight lines sections of pipes and recesses equidistant to them with the formation around each of the pipes of an individual channel connecting the mixing chambers to each other.

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

figure 1 presents a longitudinal section of a heat exchanger;

figure 2 is a section of a cross section;

figure 3 is a longitudinal section of the plate annular space;

figure 4 is a front view of the plate.

The heat exchanger comprises a housing 0 with nozzles for the inlet 1 of feed water and the outlet 2 steam, the inlet 3 of the liquid metal coolant and its outlet 4, with a bundle of heat exchange tubes 5 located inside the housing 0, spaced apart by a package of corrugated plates 6 of the annulus, and the heat exchange tubes 5 in straight sections have external screw fins 7. The plates 6 have thickenings 8 in straight sections and are equidistant to the pipes 5 of the recess 9 with the formation around each pipe of an individual screw channel 10 in communication with the mixer second chamber 11 formed near the pipe bends 5 and 6 of plates.

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 3 enters the annular space of the bundle of heat exchange tubes 5, then, due to some compression of the bore through the package of corrugated plates 6 of the annular space, hydraulic uniformity of distribution through the screw channels 10 formed by the screw fins 7 of the pipes 5 and plates 6. is provided. mixing chambers 11 formed due to the selection of ribs 7 in the places of pipe bends 5 and the corresponding removal of bulges 8 in the plates 6, the coolant is mixed for radiation temperature field in the cross section of the entire heat exchanger, which then goes through the pipe 4 of the output of the liquid metal coolant. Feed water through the inlet pipe 1 enters the distribution chamber, where the hydraulic uniformity of distribution through the heat exchange pipes 5 is ensured, and then, twisting with the help of an in-line displacer with a varying twist angle, turns into steam entering the collecting chamber, from where it leaves the steam outlet 2 .

The use of the design of the heat exchanger of the proposed type will eliminate vibration of the package of plates of the annular space in the region of the coolant inlet during the process, improve the heat transfer rate, and in the places of bending of the heat transfer pipes and, accordingly, the heat transfer medium, due to the presence of mixing chambers, the temperature field will be uniform in the cross section of the heat exchanger , which will increase the operational reliability of the design as a whole.

Information sources

1. Naumenko V.V. etc. Heat exchanger. SU a.s. No. 293490. F28D 7/00. Priority - 04.16.63. Publ. Bulletin of inventions No. 42. 09/19/1973 - analogue.

2. Weaver G.A. Shell-and-tube heat exchanger. SU a.s. No. 370441. F28D 7/00. Priority - 09/23/68. Publ. Bulletin of inventions No. 11. 02/15/73 - a prototype.

Claims (1)

A heat exchanger containing a bundle of zigzag shaped heat exchange tubes with external screw finning in straight sections mounted in the housing, spacer plates placed between the beam pipes with the formation of mixing chambers in the bending zone of the latter, characterized in that the plates have thickenings in the straight pipe sections and recesses that are equidistant to them with the formation around each of the pipes of an individual channel communicating the mixing chambers with each other.

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