CN116088593B - Low-temperature wind tunnel liquid nitrogen jet bent frame flow control method, device and storage medium - Google Patents
Low-temperature wind tunnel liquid nitrogen jet bent frame flow control method, device and storage medium Download PDFInfo
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- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 title claims abstract description 126
- 238000000034 method Methods 0.000 title claims abstract description 68
- 239000007788 liquid Substances 0.000 title claims abstract description 63
- 229910052757 nitrogen Inorganic materials 0.000 title claims abstract description 63
- 238000003860 storage Methods 0.000 title claims abstract description 15
- 238000002347 injection Methods 0.000 claims abstract description 57
- 239000007924 injection Substances 0.000 claims abstract description 57
- 239000007921 spray Substances 0.000 claims abstract description 48
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 10
- 230000009471 action Effects 0.000 claims description 34
- 238000004590 computer program Methods 0.000 claims description 17
- 238000012423 maintenance Methods 0.000 claims description 6
- 238000012216 screening Methods 0.000 claims description 5
- 238000005457 optimization Methods 0.000 claims description 4
- 230000008569 process Effects 0.000 abstract description 9
- 230000002035 prolonged effect Effects 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 9
- 238000005507 spraying Methods 0.000 description 8
- 239000000243 solution Substances 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- 230000006870 function Effects 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 238000004088 simulation Methods 0.000 description 4
- 230000008878 coupling Effects 0.000 description 3
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- 238000011161 development Methods 0.000 description 2
- 230000003287 optical effect Effects 0.000 description 2
- 230000035939 shock Effects 0.000 description 2
- 238000007664 blowing Methods 0.000 description 1
- 238000011217 control strategy Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
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- 230000008016 vaporization Effects 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
- G05D7/00—Control of flow
- G05D7/06—Control of flow characterised by the use of electric means
- G05D7/0617—Control of flow characterised by the use of electric means specially adapted for fluid materials
- G05D7/0629—Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means
- G05D7/0635—Control of flow characterised by the use of electric means specially adapted for fluid materials characterised by the type of regulator means by action on throttling means
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Abstract
The invention belongs to the field of wind tunnel temperature control, and discloses a low-temperature wind tunnel liquid nitrogen jet bent frame flow control method, a device and a storage medium. The method comprises six steps of compiling three types of nozzle index tables, calculating initial target opening amounts of the three types of nozzles, optimizing the target opening amounts of the three types of nozzles, determining the nozzle to be actuated, opening or closing the nozzle to be actuated, and finely adjusting the opening and closing states of the nozzle according to upstream flow feedback. According to the method, the target injection mass flow and the current injection pressure are taken as input, and the optimal nozzle opening and closing combination is found under the inherent limiting condition according to the current nozzle opening and closing state of the liquid nitrogen injection bent frame, so that the liquid nitrogen mass flow injected into the wind tunnel is consistent with the target injection mass flow, and the temperature fluctuation in the wind tunnel in the liquid nitrogen injection process is effectively reduced; meanwhile, the temperature uniformity of the air flow in the wind tunnel can be improved; and the service life of the nozzles on the spray bent is obviously prolonged.
Description
Technical Field
The invention relates to the field of wind tunnel temperature control, in particular to a low-temperature wind tunnel liquid nitrogen jet bent frame flow control method, a device and a storage medium.
Background
The high-temperature high-Reynolds number wind tunnel is an indispensable device for developing complex viscous flow field performance researches such as boundary layer separation, vortex flow, shock wave/boundary layer interference, shock wave/vortex interference and the like in the development process of large airplanes, advanced fighters and back-and-forth atmospheric space vehicles, and can meet the requirement of autonomous development of the advanced aerospace vehicles represented by large airliners on the simulation capability of the ground test of the flying Reynolds number. At present, the Reynolds number simulation capability of a conventional wind tunnel has obvious defects, the test simulation capability of the wind tunnel to the high Reynolds number can be greatly improved by reducing the total test temperature, and the specific method is that liquid nitrogen is sprayed to a wind tunnel loop through a liquid nitrogen spraying bent frame, and a large amount of heat can be absorbed in the liquid nitrogen vaporization process so as to reduce the test environment temperature in the wind tunnel. The liquid nitrogen spraying bent frame of the low-temperature wind tunnel is provided with 3 types of nozzles, namely a high-flow nozzle, a medium-flow nozzle and a small-flow nozzle. In the liquid nitrogen injection process, the control of the flow of liquid nitrogen injected into the low-temperature wind tunnel is realized mainly by adjusting the opening and closing states of 3 types of nozzles on the liquid nitrogen injection bent frame.
Temperature is one of the flow field parameters that is most difficult to control in low temperature wind tunnels. The liquid nitrogen jet bent is used as a main execution mechanism for controlling the temperature of the low-temperature wind tunnel, the quality of flow control of the liquid nitrogen jet bent directly influences the control performance of the test temperature of the low-temperature wind tunnel, and finally the quality of the blowing test data is influenced. The foreign large-scale low-temperature wind tunnel NTF also adopts the spray bent to spray liquid nitrogen into the hole, but the spray bent has fewer types and numbers of nozzles, the flow of the nozzles is not distinguished, and the complexity and difficulty of flow control are far less than those of the liquid nitrogen spray bent consisting of 3 types of nozzles. Currently, no such liquid nitrogen injection bent flow control method is described in the published literature and patents.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems in the related art to some extent.
Therefore, an embodiment of the first aspect of the present invention provides a flow control method for a low-temperature wind tunnel liquid nitrogen injection bent frame, where the injection bent frame includes three types of nozzles, i.e., a large-flow nozzle, a medium-flow nozzle, and a small-flow nozzle, and the flow control method includes:
three types of nozzle index tables are compiled, wherein the nozzle index tables comprise nozzle types and nozzle numbers;
calculating initial target opening numbers of three types of nozzles when the spray bent reaches target spray mass flow under a limited condition;
optimizing initial target opening numbers of the three types of nozzles according to the space uniformity requirement to obtain optimized target opening numbers of the three types of nozzles;
determining the nozzles which need to act on the spray bent according to the three types of nozzle index tables and the optimized target opening quantity of the three types of nozzles;
opening or closing the nozzles to be operated at the correct time according to the action time characteristics of each nozzle; and
and the current nozzle opening and closing state is finely adjusted by taking the actual flow of the upstream of the jet bent as feedback.
According to the technical means, the embodiment of the application solves the problem of flow control of the liquid nitrogen spraying bent frame comprising the 3-type nozzles, designs a nozzle opening and closing control strategy, and can realize accurate control of liquid nitrogen spraying flow of the spraying bent frame by adjusting the opening and closing state of the 3-type nozzles when the pressure before spraying is unchanged. Based on the method provided by the invention, the low-temperature wind tunnel can realize accurate closed-loop control of the total temperature in the tunnel by controlling liquid nitrogen injection, so as to develop a ground high Reynolds number simulation test.
Optionally, in an embodiment of the present application, the numbering method of the nozzle numbers is: numbering each nozzle according to a preset numbering range, wherein the numbers of each nozzle are different; the shorter the distance between the nozzle and the circle center of the jet bent frame is, the smaller the number is; when the distances are the same, the nozzle and the circle center of the jet bent frame are connected into a line segment, and the smaller the included angle formed by the line segment and the semi-axis on the vertical axis of the jet bent frame is, the smaller the number of the line segment is.
According to the technical means, the embodiment of the application provides a preferable nozzle numbering method, and basic guarantee is provided for determining, optimizing, controlling and the like of the opening quantity of the subsequent nozzles through orderly numbering of the nozzles.
Optionally, in an embodiment of the present application, the method for calculating the initial target opening numbers of the three types of nozzles when the spray bent reaches the target spray mass flow under the defined condition includes:
calculating mass flow coefficients of the three types of nozzles under the current injection pressure;
determining the upper limit and the lower limit of the number of the nozzles which can be opened and closed at the current moment and the number of the nozzles which can be opened at the next moment; and
and calculating the quantity of the three types of nozzles on the spray bent when the target spray mass flow is reached to be in an opening state according to the mass flow coefficient and the upper and lower limits of the quantity of the three types of nozzles which can be in the opening state.
Optionally, in an embodiment of the present application, the method for determining a nozzle capable of performing an opening and closing action at the current time includes:
obtaining the maintenance time of the current opening and closing states of all the nozzles according to the last opening and closing action time of the three types of nozzles; and
screening out nozzles which can be changed in opening and closing states from the three types of nozzles according to the maintenance time and preset conditions;
the method for determining the upper and lower limits of the number of the three types of nozzles capable of being in the open state at the next moment comprises the following steps:
calculating the number of nozzles which are currently in an opening state and can not be changed in the opening state in the three types of nozzles, wherein the number is used as the lower limit of the number of the nozzles which can be in the opening state at the next moment;
and calculating the number of the nozzles which are currently in an open state and the number of the nozzles which are currently in a closed state but can be changed in an open state in the three types of nozzles, wherein the sum of the two numbers is used as the upper limit of the number of the three types of nozzles which can be in the open state at the next moment.
Optionally, in an embodiment of the present application, the preset condition is that the nozzle cannot be opened and closed frequently; that is, only a sufficiently long nozzle in the open state allows the closing action; only nozzles in the closed state long enough to allow an opening action.
Optionally, in an embodiment of the present application, according to the mass flow coefficient and the upper and lower limits of the number of the three types of nozzles that can be in the open state, the method for calculating the number of the three types of nozzles that need to be in the open state on the spray bent when reaching the target spray mass flow needs to solve the following optimization problem with constraint:
wherein ,
is the integer number of the three types of nozzles to be opened when the target injection mass flow is reached to be solved, +.>
Respectively representing the mass flow coefficients of the three types of nozzles, < + >>
Is the target mass flow rate of the injection,
the lower limit of the number of the three types of nozzles in the open state is +.>
The upper limit of the number of the three types of nozzles in the open state is respectively set.
Optionally, in an embodiment of the present application, the method for optimizing the initial target opening numbers of the three types of nozzles according to the spatial uniformity requirement includes:
if the large-flow nozzles which are in the current opening state and can be changed in the opening and closing state exist and enough medium-flow nozzles which are in the current closing state and can be changed in the opening and closing state exist, closing one large-flow nozzle, opening the corresponding number of medium-flow nozzles, and repeating the steps;
if there are middle flow nozzles which are currently in an open state and can be changed in an open state, and there are enough small flow nozzles which are currently in a closed state and can be changed in an open state, closing one middle flow nozzle, opening a corresponding number of small flow nozzles, and repeating the steps.
Optionally, in an embodiment of the present application, the method for opening or closing the nozzle to be actuated at the correct time according to the actuation time characteristic of each nozzle includes:
according to the action time characteristics of each nozzle, counting the opening time of the nozzle needing to be opened and the closing time of the nozzle needing to be closed as the action time;
the moment that the nozzle with the longest action time is started from the current moment is taken as the cut-off moment, and the action execution starting moment of all the nozzles needing to be actuated is reversely pushed;
and opening or closing the nozzle which needs to be operated at the starting moment of the operation execution.
The embodiment of the second aspect of the invention provides a low-temperature wind tunnel liquid nitrogen jet bent flow control device, the jet bent comprises three types of nozzles, namely a large-flow nozzle, a medium-flow nozzle and a small-flow nozzle, and the flow control device comprises:
the programming module is used for programming three types of nozzle index tables, wherein the nozzle index tables comprise nozzle types and nozzle numbers;
the calculating module is used for calculating initial target opening numbers of the three types of nozzles when the spray bent reaches the target spray mass flow under the limiting condition;
the optimizing module is used for optimizing the initial target opening quantity of the three types of nozzles according to the space uniformity requirement to obtain the optimized target opening quantity of the three types of nozzles;
the determining module is used for determining the nozzles needing to act on the spray bent according to the three types of nozzle index tables and the optimized target opening quantity of the three types of nozzles;
the control module is used for opening or closing the nozzles to be operated at the correct time according to the action time characteristics of each nozzle; and
and the adjusting module is used for finely adjusting the current opening and closing state of the nozzle by taking the actual flow of the upstream of the jet bent as feedback.
An embodiment of the third aspect of the present invention provides a computer-readable storage medium having stored thereon a computer program for execution by a processor for implementing the low-temperature wind tunnel liquid nitrogen injection bent flow control method as above.
The embodiment of the application has the following effects:
according to the embodiment of the application, the target injection mass flow and the current injection pressure are taken as input, and the optimal nozzle opening and closing combination is found under the inherent limiting condition according to the current nozzle opening and closing state of the liquid nitrogen injection bent frame, so that the liquid nitrogen mass flow injected into the wind tunnel is consistent with the target injection mass flow. The liquid nitrogen injection mass flow injected into the low-temperature wind tunnel can be precisely controlled, and the temperature in the low-temperature wind tunnel can be controlled in a closed loop manner; the influence of the action characteristic of the nozzles on the spraying bent on the flow control can be avoided, and the temperature fluctuation in the wind tunnel in the liquid nitrogen spraying process is effectively reduced; meanwhile, the temperature uniformity of the air flow in the wind tunnel can be improved; and the service life of the nozzles on the spray bent is obviously prolonged.
The control method can effectively control different flow and a plurality of nozzles, and achieves accurate control of the flow of the liquid nitrogen injection bent frame.
Drawings
The foregoing and/or additional aspects and advantages of the invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a schematic view of a liquid nitrogen injection bent structure according to one embodiment of the invention;
FIG. 2 is a flow chart of a low temperature wind tunnel liquid nitrogen jet bent flow control method according to one embodiment of the invention;
FIG. 3 is a schematic diagram of a low-temperature wind tunnel liquid nitrogen jet bent flow control device according to an embodiment of the invention.
Detailed Description
In order to make the purposes, technical solutions and advantages of the implementation of the present application more clear, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the accompanying drawings in the embodiments of the present application. In the drawings, the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of the present application. The embodiments described below by referring to the drawings are exemplary and intended for the purpose of explaining the present application and are not to be construed as limiting the present application. All other embodiments, which can be made by one of ordinary skill in the art without inventive effort, are intended to be within the scope of the present application based on the embodiments herein.
In this document, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
The flow control method, system and storage medium for the low-temperature wind tunnel liquid nitrogen injection bent frame according to the embodiment of the invention are described below with reference to the accompanying drawings.
In a first aspect of the embodiments of the present application, a flow control method for a low-temperature wind tunnel liquid nitrogen injection bent is provided, where the injection bent includes three types of nozzles, i.e., a high-flow nozzle, a medium-flow nozzle, and a low-flow nozzle.
Exemplary, FIG. 1 is a schematic diagram of a liquid nitrogen jet bent frame of a low temperature wind tunnel, wherein three types of nozzles, namely a large-flow nozzle, a medium-flow nozzle and a small-flow nozzle, are installed together, different types of nozzles are represented by different shapes, and a triangle is shown in the figure "
"represents a small flow nozzle, circular">
"represents a high flow nozzle, square">
"stands for medium flow nozzle. The different types of nozzles have different calibers, so that the mass flow rate of liquid nitrogen sprayed into the holes is different under the same pressure difference. In fig. 1, there are 220 nozzles, which are uniformly distributed on 10 concentric circles on the liquid nitrogen injection bent, and their centers are the geometric centers of the surface of the whole liquid nitrogen injection bent, and each circle is provided with different types of nozzles, wherein the number of the nozzles installed on the circle with the larger inner diameter is larger. 220 nozzles are symmetrically distributed on the bent frame, and each nozzle can find a nozzle which is symmetrical with the center of the circle on the circumference, a nozzle which is symmetrical with the vertical axis of the liquid nitrogen injection bent frame and a nozzle which is symmetrical with the horizontal axis of the liquid nitrogen injection bent frame. In the liquid nitrogen injection process, the control of the flow of the liquid nitrogen injected into the low-temperature wind tunnel is realized mainly by adjusting the opening and closing states of 220 nozzles on the liquid nitrogen injection bent frame. />
As shown in fig. 2, the low-temperature wind tunnel liquid nitrogen injection bent frame flow control method comprises the following steps:
in S201, three types of nozzle index tables are prepared, including the nozzle type and the nozzle number.
Specifically, all the nozzles on the spray bar are described, the description contents at least comprise nozzle types and nozzle numbers, and the description contents form three types of nozzle index tables.
In a preferred embodiment, the specific method of the nozzle numbering is not particularly limited as long as the type and position of the nozzle can be accurately distinguished. The numbers of the numbers may be sequentially numbered regularly within a preset range, for example, may be 1, 2, 3, 4, 5, etc., or may be 10, 11, 12, 13, 14, 15, etc. The numbering rule can also be adjusted according to the actual situation.
In a preferred embodiment, the numbering method of the nozzle numbering is: numbering each nozzle according to a preset numbering range, wherein the numbers of each nozzle are different; the shorter the distance between the nozzle and the circle center of the jet bent frame is, the smaller the number is; when the distances are the same, the nozzle and the circle center of the jet bent frame are connected into a line segment, and the smaller the included angle formed by the line segment and the semi-axis on the vertical axis of the jet bent frame is, the smaller the number of the line segment is.
Illustratively, the nozzles of FIG. 1 are numbered, 220 nozzles on a liquid nitrogen injection bent are numbered from 1 to 220, and the shorter the distance from the center of the injection bent, the smaller the number of the nozzles; when the distances are the same, the nozzle and the circle center of the jet bent frame are connected into a line segment, and the smaller the included angle formed by the line segment and the semi-axis on the vertical axis of the jet bent frame is, the smaller the number of the line segment is.
In a preferred embodiment, in order to make the nozzle information in the three types of index tables more detailed and comprehensive, the index table may describe each nozzle by five-tuple, where the five-tuple includes the type of the nozzle, the number of the nozzle symmetrical about the center of the circle center of the spray bent, the number of the nozzle symmetrical about the vertical axis of the spray bent, and the number of the nozzle symmetrical about the horizontal axis of the spray bent, and all the five-tuple corresponding to the nozzle forms the nozzle index table of the liquid nitrogen spray bent.
In S202, the initial target opening numbers of the three types of nozzles when the spray bent reaches the target spray mass flow under the limiting condition are calculated.
In a preferred embodiment, the method of calculating the initial target opening amounts of the three types of nozzles when the spray bent reaches the target spray mass flow under the defined conditions comprises:
calculating mass flow coefficients of the three types of nozzles under the current injection pressure; determining the upper limit and the lower limit of the number of the nozzles which can be opened and closed at the current moment and the number of the nozzles which can be opened at the next moment; and calculating the quantity of the three types of nozzles on the spray bent when the target spray mass flow is reached, wherein the quantity of the three types of nozzles is required to be in an open state according to the mass flow coefficient and the upper and lower limits of the quantity of the three types of nozzles which can be in an open state.
In a preferred embodiment, the method for determining the nozzle capable of performing the opening and closing actions at the current moment comprises the following steps: obtaining the maintenance time of the current opening and closing states of all the nozzles according to the last opening and closing action time of the three types of nozzles; and screening out nozzles which can be changed in opening and closing states from the three types of nozzles according to the maintenance time and preset conditions.
In one specific embodiment, according to the last opening and closing action time of the three types of nozzles, the specific method for obtaining the maintaining time of the current opening and closing state of all the nozzles is as follows: for the nozzle in the open state, the duration of time that it was in the open state is calculated, and for the nozzle in the closed state, the duration of time that it was in the closed state is calculated.
In a specific embodiment, the method for determining the upper and lower limits of the number of the three types of nozzles capable of being in the open state at the next moment includes: according to the limiting condition that the nozzles cannot be frequently opened and closed, namely, only the nozzles in the opening state are long enough to allow closing actions, and only the nozzles in the closing state are long enough to allow opening actions, the nozzles in the three types of nozzles, the opening and closing states of which can be changed, are screened out; for example, the same nozzle cannot be repeatedly turned on and off within the limit 5s, and if a nozzle 3s is detected to be previously turned on, the nozzle cannot be turned off at the present time.
Calculating the number of nozzles which are currently in an opening state and can not be changed in the opening state in the three types of nozzles, wherein the number is used as the lower limit of the number of the nozzles which can be in the opening state at the next moment; and calculating the number of the nozzles which are currently in an open state and the number of the nozzles which are currently in a closed state but can be changed in an open state in the three types of nozzles, wherein the sum of the two numbers is used as the upper limit of the number of the three types of nozzles which can be in the open state at the next moment.
In a specific embodiment, according to the mass flow coefficient and the upper and lower limits of the number of the three types of nozzles capable of being in an opened state, the method for calculating the number of the three types of nozzles on the spray bent when reaching the target spray mass flow needs to be in the opened state, and the following optimization problem with constraint needs to be solved:
wherein ,
is an integer, is the number of three types of nozzles to be in an open state when the target injection mass flow is reached to be solved, < >>
Respectively representing the mass flow coefficients of the three types of nozzles, < + >>
Is the target mass flow rate of the injection,
the lower limit of the number of the three types of nozzles in the open state is +.>
The upper limit of the number of the three types of nozzles in the open state is respectively set.
In S203, the initial target opening numbers of the three types of nozzles are optimized according to the spatial uniformity requirement, so as to obtain the optimized target opening numbers of the three types of nozzles.
In some preferred embodiments, the method of optimizing the initial target opening amounts of three types of nozzles according to spatial uniformity requirements comprises:
if the large-flow nozzles which are in the opening state at present and can be changed in the opening and closing state exist, and enough medium-flow nozzles which are in the closing state at present and can be changed in the opening and closing state exist, closing one large-flow nozzle, opening the corresponding number of medium-flow nozzles, and repeatedly executing the operation until the preconditions are not met, so that the target opening quantity of the large-flow nozzles after optimization is obtained.
If there are middle flow nozzles which are in the opening state and can be changed in the opening state, and there are enough small flow nozzles which are in the closing state and can be changed in the opening state, closing one middle flow nozzle, opening the corresponding number of small flow nozzles, and repeatedly executing the operation until the precondition is not met, so as to obtain the target opening quantity of the optimized middle flow nozzles and the optimized small flow nozzles.
In S204, the nozzles on the spray bar that need to be operated are determined according to the three types of nozzle index tables and the optimized target opening amounts of the three types of nozzles.
In some embodiments, for three types of nozzles, if the target opening number of the types of nozzles is greater than the number of nozzles currently in an open state, setting the target opening and closing states of the types of nozzles already in the open state to be open, and setting the target opening and closing states of the other types of nozzles to be closed; if the target opening quantity of the nozzles is smaller than the current opening quantity of the nozzles, the target opening and closing states of the nozzles in the closed state are set to be closed, the target opening and closing states of the other nozzles are set to be opened, and screening is carried out according to the sequence of increasing numbers.
The nozzle number of each nozzle is found from the nozzle index table, the nozzle number of each nozzle is symmetrical about the center of the circle center of the spray bent, the nozzle number of each nozzle is symmetrical about the vertical axis of the spray bent, the nozzle number of each nozzle is symmetrical about the horizontal axis of the spray bent, the quaternary symmetrical nozzle groups are formed, and the opening number of the nozzles of each quaternary symmetrical nozzle group is counted.
When the target opening quantity of the type of nozzles is larger than the quantity of nozzles with opening states being opened, quaternary symmetrical nozzle groups with the opening quantity of the nozzles being smaller than 4 are screened, the quaternary symmetrical nozzle groups are sequentially processed according to the opening quantity from large to small, and for each quaternary symmetrical nozzle group, the target opening and closing states of the nozzles meeting the opening conditions are sequentially set to be opened according to the nozzle numbers from small to large.
When the target opening quantity of the type of nozzles is smaller than the quantity of nozzles with the target opening and closing states being opened, quaternary symmetrical nozzle groups with the opening quantity of the nozzles being larger than 0 are screened, the quaternary symmetrical nozzle groups are sequentially processed according to the opening quantity from small to large, and for each quaternary symmetrical nozzle group, the target opening and closing states of the nozzles meeting the closing conditions are sequentially set to be closed according to the nozzle numbers from small to small.
Comparing the current opening and closing state and the target opening and closing state of each nozzle, wherein the nozzles with inconsistent two states are the nozzles needing to act.
In S205, the nozzles to be operated are turned on or off at the correct time according to the operation time characteristics of each nozzle.
In some preferred embodiments, according to the action time characteristics of each nozzle, counting the opening time of the nozzle needing to be opened and the closing time of the nozzle needing to be closed as the action time thereof; the moment that the nozzle with the longest action time is started from the current moment is taken as the cut-off moment, and the action execution starting moment of all the nozzles needing to be actuated is reversely pushed; and opening or closing the nozzle which needs to be operated at the starting moment of the operation execution.
In S206, the current nozzle opening and closing state is fine-tuned by taking the actual flow upstream of the spray bent as feedback.
The purpose of this step trimming is to bring the flow actually injected into the wind tunnel as close as possible to the target injection flow.
In one specific embodiment, reading an upstream flowmeter of the jet bent, and calculating the number of small-flow nozzles which need to be opened or closed to compensate the difference value according to the difference value between the upstream flowmeter and the target jet mass flow; when a small quantity of small-flow nozzles are required to be opened, small-flow quaternary symmetrical nozzle groups with the opening quantity of the nozzles being smaller than 4 are screened out, the quaternary symmetrical nozzle groups are sequentially processed from large to small according to the opening quantity, and for each quaternary symmetrical nozzle group, the target opening and closing states of the small-flow nozzles meeting the opening conditions are sequentially set to be opened from small to large according to the nozzle numbers; when a small quantity of small-flow nozzles are required to be closed, small-flow quaternary symmetrical nozzle groups with the opening quantity of the nozzles being more than 0 are screened out, the quaternary symmetrical nozzle groups are sequentially processed from small to large according to the opening quantity, and for each quaternary symmetrical nozzle group, the target opening and closing states of the small-flow nozzles meeting the closing conditions are sequentially set to be closed from large to small according to the nozzle numbers; and screening out the small-flow nozzles with inconsistent current opening and closing states and target opening and closing states, and executing corresponding target actions.
In summary, the method of the embodiment of the present application includes six steps of compiling three types of nozzle index tables, calculating initial target opening amounts of the three types of nozzles, optimizing the target opening amounts of the three types of nozzles, determining the nozzle to be actuated, opening or closing the nozzle to be actuated, and fine-tuning the opening and closing state of the nozzle according to upstream flow feedback. According to the method, target injection mass flow and current injection pressure are taken as input, and an optimal nozzle opening and closing combination is found under the inherent limiting condition according to the current nozzle opening and closing state of the liquid nitrogen injection bent frame, so that the liquid nitrogen mass flow injected into the wind tunnel is consistent with the target injection mass flow. Meanwhile, the method can also ensure that the mass flow of the liquid nitrogen sprayed into the wind tunnel cannot excessively fluctuate due to the action characteristic of the nozzles even when a large number of nozzles are opened and closed, and meets the requirement of temperature control of the low-temperature wind tunnel through the mass of the liquid nitrogen sprayed.
Next, a low-temperature wind tunnel liquid nitrogen injection bent flow control system according to an embodiment of the invention is described with reference to the accompanying drawings.
FIG. 3 is a schematic diagram of a low-temperature wind tunnel liquid nitrogen jet bent flow control device according to an embodiment of the invention.
As shown in fig. 3, the low-temperature wind tunnel liquid nitrogen injection bent flow control device 30 includes: the jet stack comprises a compiling module 301, a calculating module 302, an optimizing module 303, a determining module 304, a control module 305 and an adjusting module 306, wherein the jet stack comprises three types of nozzles, namely a high-flow nozzle, a medium-flow nozzle and a low-flow nozzle.
The compiling module 301 is configured to compile three types of nozzle index tables, where the nozzle index table includes a nozzle type and a nozzle number;
the calculating module 302 is used for calculating initial target opening numbers of the three types of nozzles when the spray bent reaches the target spray mass flow under the limiting condition;
the optimizing module 303 is configured to optimize initial target opening numbers of the three types of nozzles according to the spatial uniformity requirement, so as to obtain optimized target opening numbers of the three types of nozzles;
the determining module 304 is configured to determine a nozzle that needs to act on the spray bent according to the three types of nozzle index tables and the optimized target opening number of the three types of nozzles;
a control module 305, configured to open or close the nozzles to be operated at a correct time according to the operation time characteristics of each nozzle; and
the adjusting module 306 is configured to finely adjust the current nozzle opening and closing state by using the actual flow rate of the upstream of the spray bent as feedback.
It should be noted that, in the foregoing embodiments, the descriptions of the embodiments are focused on, and for those portions of one embodiment that are not described in detail, reference may be made to the related descriptions of other embodiments.
It will be appreciated by those skilled in the art that embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-readable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-readable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
A third aspect of the embodiments of the present application provides a computer-readable storage medium having stored thereon a computer program for execution by a processor for implementing the low temperature wind tunnel liquid nitrogen injection bent flow control method as above.
The module/unit of the low temperature wind tunnel liquid nitrogen injection bent flow control device/terminal equipment integration can be stored in a computer readable storage medium if implemented in the form of a software functional unit and sold or used as a separate product. Based on such understanding, the present invention may implement all or part of the flow of the method of the above embodiment, or may be implemented by a computer program to instruct related hardware, where the computer program may be stored in a computer readable storage medium, and when the computer program is executed by a processor, the computer program may implement the steps of each of the method embodiments described above.
Wherein the computer program comprises computer program code which may be in source code form, object code form, executable file or some intermediate form etc. The computer readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a U disk, a removable hard disk, a magnetic disk, an optical disk, a computer memory, a Read-only memory (ROM), a random access memory (RAM, random Access Memory), an electrical carrier signal, a telecommunications signal, a software distribution medium, and so forth. It should be noted that the computer readable medium contains content that can be appropriately scaled according to the requirements of jurisdictions in which such content is subject to legislation and patent practice, such as in certain jurisdictions in which such content is subject to legislation and patent practice, the computer readable medium does not include electrical carrier signals and telecommunication signals.
In the several embodiments provided in this application, it should be understood that the disclosed apparatus, device, and method may be implemented in other manners. For example, the apparatus embodiments described above are merely illustrative, e.g., the division of elements is merely a logical functional division, and there may be additional divisions of actual implementation, e.g., multiple elements or components may be combined or integrated into another system, or some features may be omitted, or not performed. Alternatively, the coupling or direct coupling or communication connection shown or discussed with each other may be an indirect coupling or communication connection via some interfaces, devices or units, which may be in electrical, mechanical, or other forms.
The units described as separate units may or may not be physically separate, and units shown as units may or may not be physical units, may be located in one place, or may be distributed over a plurality of network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
In addition, each functional unit in each embodiment of the present application may be integrated in one processing unit, or each unit may exist alone physically, or two or more units may be integrated in one unit. The integrated units may be implemented in hardware or in software functional units.
The integrated units, if implemented in the form of software functional units and sold or used as stand-alone products, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present application may be embodied in essence or a part contributing to the prior art or all or part of the technical solution in the form of a software product stored in a storage medium, including several instructions to cause a computer device (which may be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods of the embodiments of the present application.
The above embodiments are only for illustrating the technical solution of the present application, and are not limiting thereof; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.
Claims (7)
1. The low-temperature wind tunnel liquid nitrogen jet bent flow control method is characterized in that the jet bent comprises three types of nozzles, namely a large-flow nozzle, a medium-flow nozzle and a small-flow nozzle, and the method comprises the following steps:
three types of nozzle index tables are compiled, wherein the nozzle index tables comprise nozzle types and nozzle numbers;
calculating initial target opening numbers of three types of nozzles when the spray bent reaches target spray mass flow under a limited condition;
optimizing initial target opening numbers of the three types of nozzles according to the space uniformity requirement to obtain optimized target opening numbers of the three types of nozzles;
determining the nozzles which need to act on the spray bent according to the three types of nozzle index tables and the optimized target opening quantity of the three types of nozzles;
opening or closing the nozzles to be operated at the correct time according to the action time characteristics of each nozzle; and
the current nozzle opening and closing state is finely adjusted by taking the upstream actual flow of the jet bent as feedback;
the method for calculating the initial target opening quantity of the three types of nozzles when the spray bent reaches the target spray mass flow under the limiting condition comprises the following steps:
calculating mass flow coefficients of the three types of nozzles under the current injection pressure;
determining the upper limit and the lower limit of the number of the nozzles which can be opened and closed at the current moment and the number of the nozzles which can be opened at the next moment; and
according to the mass flow coefficient and the upper and lower limits of the number of the three types of nozzles which can be in an opening state, calculating the number of the three types of nozzles which need to be in an opening state when the target injection mass flow is reached;
the method for optimizing the initial target opening quantity of three types of nozzles according to the space uniformity requirement comprises the following steps:
if the large-flow nozzles which are in the current opening state and can be changed in the opening and closing state exist and enough medium-flow nozzles which are in the current closing state and can be changed in the opening and closing state exist, closing one large-flow nozzle, opening the corresponding number of medium-flow nozzles, and repeating the steps;
if there are middle flow nozzles which are in the opening state at present and can be changed in the opening and closing state, and there are enough small flow nozzles which are in the closing state at present and can be changed in the opening and closing state, closing one middle flow nozzle, opening a corresponding number of small flow nozzles, and repeating the steps;
the method for opening or closing the nozzles to be operated at the correct time according to the operation time characteristics of each nozzle comprises the following steps:
according to the action time characteristics of each nozzle, counting the opening time of the nozzle needing to be opened and the closing time of the nozzle needing to be closed as the action time;
the moment that the nozzle with the longest action time is started from the current moment is taken as the cut-off moment, and the action execution starting moment of all the nozzles needing to be actuated is reversely pushed;
and opening or closing the nozzle which needs to be operated at the starting moment of the operation execution.
2. The low-temperature wind tunnel liquid nitrogen jet bent flow control method according to claim 1, wherein the numbering method of the nozzle number is as follows: numbering each nozzle according to a preset numbering range, wherein the numbers of each nozzle are different; the shorter the distance between the nozzle and the circle center of the jet bent frame is, the smaller the number is; when the distances are the same, the nozzle and the circle center of the jet bent frame are connected into a line segment, and the smaller the included angle formed by the line segment and the semi-axis on the vertical axis of the jet bent frame is, the smaller the number of the line segment is.
3. The method for controlling the flow rate of the low-temperature wind tunnel liquid nitrogen jet bent frame according to claim 1, wherein the method for determining the nozzle capable of performing the opening and closing actions at the current moment comprises the following steps:
obtaining the maintenance time of the current opening and closing states of all the nozzles according to the last opening and closing action time of the three types of nozzles; and
screening out nozzles which can be changed in opening and closing states from the three types of nozzles according to the maintenance time and preset conditions;
the method for determining the upper and lower limits of the number of the three types of nozzles capable of being in the open state at the next moment comprises the following steps:
calculating the number of nozzles which are currently in an opening state and can not be changed in the opening state in the three types of nozzles, wherein the number is used as the lower limit of the number of the nozzles which can be in the opening state at the next moment;
and calculating the number of the nozzles which are currently in an open state and the number of the nozzles which are currently in a closed state but can be changed in an open state in the three types of nozzles, wherein the sum of the two numbers is used as the upper limit of the number of the three types of nozzles which can be in the open state at the next moment.
4. The low-temperature wind tunnel liquid nitrogen injection bent flow control method according to claim 3, wherein the preset condition is that a nozzle cannot be frequently opened and closed; that is, only the nozzle in the open state is allowed to perform the closing operation, and only the nozzle in the closed state is allowed to perform the opening operation.
5. The method for controlling the flow rate of the low-temperature wind tunnel liquid nitrogen injection bent frame according to claim 1 is characterized in that the method for calculating the number of the three types of nozzles on the injection bent frame to be in the opening state when reaching the target injection mass flow rate according to the mass flow coefficient and the upper limit and the lower limit of the number of the three types of nozzles which can be in the opening state is required to solve the following optimization problem with constraint:
wherein ,
is an integer, is the number of three types of nozzles to be in an open state when the target injection mass flow is reached to be solved, < >>
Respectively representing the mass flow coefficients of the three types of nozzles, < + >>
Is the target mass flow rate of the injection,
the lower limit of the number of the three types of nozzles in the open state is +.>
The upper limit of the number of the three types of nozzles in the open state is respectively set.
6. The low-temperature wind tunnel liquid nitrogen jet bent flow control device is characterized in that the jet bent comprises three types of nozzles, namely a large-flow nozzle, a medium-flow nozzle and a small-flow nozzle, and comprises:
the programming module is used for programming three types of nozzle index tables, wherein the nozzle index tables comprise nozzle types and nozzle numbers;
the calculating module is used for calculating initial target opening numbers of the three types of nozzles when the spray bent reaches the target spray mass flow under the limiting condition;
the optimizing module is used for optimizing the initial target opening quantity of the three types of nozzles according to the space uniformity requirement to obtain the optimized target opening quantity of the three types of nozzles;
the determining module is used for determining the nozzles needing to act on the spray bent according to the three types of nozzle index tables and the optimized target opening quantity of the three types of nozzles;
the control module is used for opening or closing the nozzles to be operated at the correct time according to the action time characteristics of each nozzle; and
the adjusting module is used for finely adjusting the current nozzle opening and closing state by taking the actual flow of the upstream of the jet bent as feedback;
the calculating module is also used for calculating mass flow coefficients of the three types of nozzles under the current injection pressure; determining the upper limit and the lower limit of the number of the nozzles which can be opened and closed at the current moment and the number of the nozzles which can be opened at the next moment; according to the mass flow coefficient and the upper and lower limits of the number of the three types of nozzles which can be in an open state, calculating the number of the three types of nozzles which need to be in an open state when the target injection mass flow is reached;
the optimizing module is also used for closing one large-flow nozzle and opening a corresponding number of medium-flow nozzles if the large-flow nozzle which is in the current opening state and can be changed in the opening state exists and enough medium-flow nozzles which are in the current closing state and can be changed in the opening state exist; if there are middle flow nozzles which are in the opening state at present and can be changed in the opening and closing state, and there are enough small flow nozzles which are in the closing state at present and can be changed in the opening and closing state, closing one middle flow nozzle, opening a corresponding number of small flow nozzles, and repeating the steps;
the control module is also used for counting the opening time of the nozzle needing to be opened and the closing time of the nozzle needing to be closed according to the action time characteristic of each nozzle as the action time; the moment that the nozzle with the longest action time is started from the current moment is taken as the cut-off moment, and the action execution starting moment of all the nozzles needing to be actuated is reversely pushed;
and opening or closing the nozzle which needs to be operated at the starting moment of the operation execution.
7. A computer readable storage medium having stored thereon a computer program, wherein the program is executed by a processor for implementing the low temperature wind tunnel liquid nitrogen injection bent flow control method according to any one of claims 1 to 5.
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| KR101348724B1 (en) * | 2012-04-16 | 2014-01-09 | 국방과학연구소 | The mass-flow control device for super sonic wind-tunnel testing and wind-tunnel testing apparatus having the same |
| CN103033334A (en) * | 2012-12-19 | 2013-04-10 | 中国航空工业集团公司沈阳空气动力研究所 | Testing device of flow measurement and control used in aerospace |
| CN203083802U (en) * | 2012-12-19 | 2013-07-24 | 中国航空工业集团公司沈阳空气动力研究所 | Flow measuring and controlling experiment device practical for aviation/aerospace |
| CN103365306B (en) * | 2013-06-28 | 2016-08-10 | 中国空气动力研究与发展中心高速空气动力研究所 | A kind of high-speed wind tunnel special test compressed air require adjusting means and method |
| CA2919507C (en) * | 2013-07-12 | 2023-03-07 | John C. Karamanos | Fluid control measuring device |
| CN104634536A (en) * | 2015-01-28 | 2015-05-20 | 天津大学 | Economic and efficient opening direct current type ice wind tunnel |
| US20180281930A1 (en) * | 2017-03-31 | 2018-10-04 | U.S.A. as represented by the Administrator of NASA | Spanwise Traveling Electro Pneumatic Actuator Systems and Control Logic for Flow Control Applications |
| CN106959201B (en) * | 2017-05-18 | 2023-02-28 | 西北工业大学 | Continuous high-speed wind tunnel liquid nitrogen cooling gas supply and distribution system |
| CN107885258B (en) * | 2017-12-06 | 2019-11-22 | 西北工业大学 | A kind of cooling wind-tunnel temprature control method based on solenoid valve combination |
| CN113701987B (en) * | 2021-08-26 | 2022-07-29 | 中国科学院力学研究所 | High-pressure gas flow control device for wind tunnel test |
| CN115371943B (en) * | 2022-10-26 | 2022-12-23 | 中国空气动力研究与发展中心设备设计与测试技术研究所 | Jet bent frame device for realizing wind tunnel cooling by using liquid nitrogen medium |
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