Disclosure of Invention
In order to make up for the defects, the invention provides the asymmetric inverted U-shaped tube bundle steam generator for the reactor, which has the functions of increasing the height difference of a cold source and a heat source of a loop, reducing the range of a negative slope region of a flow-pressure drop curve and relieving the occurrence of a backflow phenomenon.
The invention is realized by the following steps:
the asymmetric inverted U-shaped tube bundle steam generator comprises an inlet cavity and an outlet cavity, wherein an inlet cavity connecting pipe is arranged at the top of the inlet cavity, an outlet cavity connecting pipe is arranged on one side of the outlet cavity, the inlet cavity connecting pipe and the outlet cavity connecting pipe are communicated through the asymmetric inverted U-shaped tube bundle, a cooling device is arranged outside the asymmetric inverted U-shaped tube bundle and used for cooling hot fluid in the asymmetric inverted U-shaped tube bundle, the asymmetric inverted U-shaped tube bundle is composed of a first pipeline and a second pipeline, the first pipeline and the second pipeline are identical in length, and the first pipeline and the second pipeline are different in length.
Furthermore, the first pipeline and the second pipeline are matched in shape and are positioned on the same vertical plane, and two ends of the first pipeline and two ends of the second pipeline are respectively positioned on the same horizontal plane.
Further, an inlet tube plate is arranged at the top of the inlet chamber and is a semicircular plate, and the inlet tube plate is used for installing an inlet chamber connecting tube.
Furthermore, an outlet tube plate is arranged on one side of the outlet chamber and is a rectangular plate, and the outlet tube plate is used for installing the outlet chamber connecting tube.
Further, the outlet chamber is located at a bottom position of the inlet chamber.
Further, the cooling device is a secondary side fluid pipe, and the secondary side fluid is used for cooling the hot fluid in the asymmetric inverted U-shaped tube bundle through the secondary side fluid.
The invention has the beneficial effects that:
after the asymmetrical inverted U-shaped tube bundle is adopted, the height difference of a cold source and a heat source of a loop can be increased, and the range of a negative slope area of a flow-pressure drop curve is reduced and the backflow phenomenon is reduced.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings of the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the equipment or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
Referring to fig. 1-5, the present invention provides the following technical solutions: reactor asymmetric inverted U-shaped tube bundle steam generator, including inlet chamber 200 and export chamber 300, the top of inlet chamber 200 is provided with inlet chamber takeover 202, one side of export chamber 300 is provided with export chamber takeover 302, inlet chamber takeover 202 and export chamber takeover 302 are through asymmetric inverted U-shaped tube bundle intercommunication, the outside of asymmetric inverted U-shaped tube bundle is provided with cooling device 400, cooling device 400 is used for cooling the interior hot-fluid of asymmetric inverted U-shaped tube bundle, asymmetric inverted U-shaped tube bundle comprises pipeline one 101 and pipeline two 102 of internal and external diameter, material, the import and export resistance unanimity, the length of pipeline one 101 is inequality with pipeline two 102.
Because the space of the cabin where the reactor of the marine nuclear power device is located is limited, the height of the steam generator is difficult to increase, the structural design of the asymmetric U-shaped pipe can obviously increase the height difference between the descending section and the ascending section of the asymmetric U-shaped pipe under the condition that the height of the steam generator is not changed, so that the gravity pressure drop of the asymmetric U-shaped pipe is increased, and the backflow phenomenon is slowed down.
For the asymmetric inverted U-shaped tube bundle, an ascending straight tube section is set to be HuThe descending straight pipe section is HdThen, then
The total gravity pressure drop is:
the expression of the gravity pressure drop of the ascending section minus the gravity pressure drop of the descending section is:
the bending section gravity pressure drop expression is as follows:
thus, formula (2) and formula (3) can be substituted for formula (1):
the total pressure drop is
By using the mathematical physical model of the asymmetric U-shaped pipe 100, the operation and structural parameters of an inverted U-shaped pipe in a steam generator of a certain nuclear power plant are taken as calculation objects, the height difference between a descending section and an ascending section is increased, the improvement effect of the asymmetric U-shaped pipe is calculated and analyzed from the two aspects of backflow critical mass flow and backflow critical pressure drop, the U-shaped pipe with the length of L is selected, the total pipe length is kept unchanged, three improvement schemes that the height difference between the descending section and the ascending section is increased to be 0.08L, 0.12L and 0.16L respectively are provided, and the calculation is carried out under the set working conditions 1, 2, 3 and 4. Working conditions 1 and 2 are natural circulation power operation working conditions, and working conditions 3 and 4 are secondary side passive waste heat removal working conditions. All data in table 1, table 2 and figures 2-5 were normalized.
TABLE 1 Steady-State calculation Condition List
Calculating the running conditions of the optimization schemes under different working conditions to obtain a change relation curve of total pressure drop of the inlet and the outlet along with the flow, making figures 2 to 5, and comparing the backflow critical mass flow of different optimization schemes under different working conditions with the flow ratio shown in table 2.
TABLE 2 critical flow of backflow under different conditions for different optimization schemes
Under the working condition of natural circulation, the flow-pressure drop curve has a negative slope region, when the fluid in the inverted U-shaped tube works in the negative slope region, the backflow phenomenon can occur, and the backflow phenomenon can be obviously weakened by reducing the flow range of the negative slope region. As can be seen from fig. 1-4 and table 2, under the same working condition, the backflow critical flow rate gradually decreases with the increase of the height difference between the descending section and the ascending section, which means that the range of the negative slope region of the flow-pressure drop curve is obviously reduced, and the absolute value of the backflow critical pressure drop gradually increases, indicating that the backflow phenomenon is more difficult to occur in the asymmetric U-shaped pipe than in the symmetric U-shaped pipe under the natural circulation power operating condition and the secondary side passive waste heat discharging condition, and the increase of the height difference between the descending section and the ascending section can obviously and slowly reduce the backflow phenomenon.
The inner and outer diameters, materials and inlet and outlet resistances of the asymmetric U-shaped tube bundle 100 are completely consistent with those of the original inverted U-shaped tube, and the length of the ascending straight tube section is HuThe length of the descending straight segment is HdThat is, the sum of the two sections is the same as the length of the original inverted U-shaped pipe, and in order to increase the height difference between the descending section and the ascending section, the outlet chamber 300 is placed at the inletUnder the chamber 200, in normal operation, hot fluid flowing out of the reactor core enters the inlet chamber from the inlet chamber connecting pipe 202, then flows through the asymmetric inverted U-shaped tube bundle 100, and after heat transfer cooling is performed on the fluid and secondary side fluid outside the tube, the cooled fluid flows downwards into the outlet chamber 300, and then flows out of the outlet chamber 300, and flows into the core through a pipeline to absorb heat generated by the core, so that circular flow is formed.
To meet the amount of fluid charge in the steam generator, the volume of the inlet and outlet chambers 200, 300 is guaranteed to be the same as the volume of the prototype steam generator inlet and outlet chambers 200, 300.
The first pipeline 101 and the second pipeline 102 are matched in shape and are located on the same vertical plane, and two ends of the first pipeline 101 and two ends of the second pipeline 102 are located on the same horizontal plane respectively.
The top of the inlet chamber 200 is provided with an inlet tube plate 201, the inlet tube plate 201 is a semicircular plate, and the inlet tube plate 201 is used for installing an inlet chamber connecting tube 202.
An outlet tube plate 301 is arranged on one side of the outlet chamber 300, the outlet tube plate 301 is a rectangular plate, and the outlet tube plate 301 is used for installing an outlet chamber connecting tube 302.
The outlet chamber 300 is located at the bottom position of the inlet chamber 200.
The cooling device 400 is a secondary side fluid pipe, and the secondary side fluid is used for cooling the thermal fluid in the asymmetric inverted U-shaped tube bundle through the secondary side fluid.
When the asymmetric inverted U-shaped tube bundle steam generator of the reactor normally operates, hot fluid flowing out of a reactor core of the reactor enters an inlet chamber from an inlet chamber connecting pipe 202, then flows through the asymmetric inverted U-shaped tube bundle 100, and after heat transfer cooling is carried out on the fluid and fluid on the secondary side outside the tube, the cooled fluid flows downwards into an outlet chamber 300, flows out of the outlet chamber 300, flows into the reactor core through a pipeline, absorbs heat generated by the reactor core, and forms circular flow.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.