Optimal blade angle simulation method and system of variable pitch propeller aircraft in taxiing and takeoff stage

Abstract

The invention relates to a method and a system for simulating an optimal blade angle of a variable pitch propeller aircraft in a takeoff stage. The method comprises the following steps: acquiring a relational expression of propeller thrust, a propeller thrust coefficient and a pitch ratio; according to the maximum rotating speed in the engine envelope, the maximum rotating speed of the propeller is determined; according to the maximum rotation speed of the propeller and the relational expression of the incoming flow speed, the rotation speed of the propeller and the pitch ratio, the minimum pitch ratio of the variable pitch propeller under each blade angle when the thrust is maximum is obtained; obtaining a propeller thrust coefficient corresponding to each minimum pitch ratio; and according to the minimum pitch ratio and the propeller thrust coefficient corresponding to the minimum pitch ratio, the optimal blade angle when the propeller thrust is maximum is obtained. The design of the optimal blade angle of the propeller of the aircraft in the taxiing take-off stage is achieved, and therefore it is guaranteed that the aircraft outputs the maximum thrust at each moment in the taxiing take-off stage.

Description

Technical Field

[0001] The invention relates to the technical field of propeller design, and in particular to an optimal blade angle simulation method and system for a variable pitch propeller aircraft during a taxiing and take-off phase. Background Art

[0002] In the aviation field, propeller aircraft have broad application prospects in various application scenarios such as regional air transportation, agriculture and environmental monitoring due to their relatively simple structure and low operating cost advantages. In the technical development of propeller aircraft, the power system as the "heart" of the aircraft is the core of the overall design of the aircraft. During takeoff and climb, the performance of the propeller power system directly affects the working efficiency and stability of the entire aircraft system. However, due to the influence of environmental factors such as wind speed and changes in the aircraft itself, the optimal blade angle of the propeller at each moment during the taxiing takeoff is also changing continuously. At present, domestic power system research lacks research on the optimal blade angle of variable pitch propellers at different moments during the taxiing takeoff, and cannot fully utilize the advantages of variable pitch propellers during the taxiing takeoff process.

[0003] With the development of computer technology and the improvement of data processing capabilities, efficient and accurate power system simulation methods have gradually become a research hotspot. These methods can not only provide more detailed parameter analysis, but also simulate the performance of propellers under different working conditions in real time, providing an important reference for optimal design. However, there is currently a lack of simulation methods specifically designed for variable pitch propellers during the rolling takeoff phase, which limits its further application and development in related fields.

[0004] Therefore, it is necessary to provide a method and system for simulating the optimal blade angle of a variable pitch propeller aircraft during the rolling takeoff phase to solve the above problems. Summary of the invention

[0005] The invention provides an optimal blade angle simulation method and system for a variable pitch propeller aircraft in a taxiing take-off phase, so as to solve the existing problems.

[0006] The optimal blade angle simulation method and system of a variable pitch propeller aircraft in the taxiing takeoff phase of the present invention adopts the following technical solutions, including: According to the relationship between the propeller thrust and the propeller speed at a certain moment in the aircraft's rolling takeoff phase, and the relationship between the incoming flow speed, the propeller speed and the pitch ratio, the relationship between the propeller thrust, the propeller thrust coefficient and the pitch ratio is obtained; Determine the maximum propeller speed based on the maximum speed within the engine envelope; According to the maximum propeller speed, and the relationship between the incoming flow speed, propeller speed and pitch ratio, the minimum pitch ratio of the variable pitch propeller at each blade angle when the thrust is maximum is obtained; Obtain the propeller thrust coefficient corresponding to each minimum pitch ratio; The optimal blade angle when the propeller thrust is maximum is obtained according to the minimum pitch ratio and its corresponding propeller thrust coefficient.

[0007] Preferably, the relationship between propeller thrust and propeller speed is:

[0008] In the formula, Indicates propeller thrust; represents the propeller thrust coefficient; Indicates propeller speed; Indicates the propeller diameter; Indicates the air density at the takeoff altitude.

[0009] Preferably, the relationship between the incoming flow velocity, propeller speed and pitch ratio is:

[0010] In the formula, Indicates the distance ratio; Indicates the propeller diameter; Indicates propeller speed; Indicates the incoming flow velocity.

[0011] Preferably, the relationship between propeller thrust, propeller thrust coefficient and pitch ratio is:

[0012]

[0013] In the formula, Indicates propeller thrust; Indicates the distance ratio; represents the propeller thrust coefficient; Indicates the propeller diameter; Indicates propeller speed; Indicates the air density at the take-off altitude; Indicates the incoming flow velocity.

[0014] Preferably, the steps of determining the maximum speed of the propeller according to the maximum speed in the engine envelope are:

[0015] In the formula, Indicates the maximum propeller speed; Indicates the maximum speed within the engine envelope; Indicates the reduction ratio between the propeller and the engine.

[0016] Preferably, the step of obtaining the propeller thrust coefficient corresponding to each minimum pitch ratio is: Wind tunnel tests were carried out on variable pitch propellers with different blade angles at minimum pitch ratios, and the propeller thrust coefficient corresponding to each minimum pitch ratio was obtained.

[0017] Preferably, the step of obtaining the optimal blade angle when the propeller thrust is maximum according to the minimum pitch ratio and the propeller thrust coefficient corresponding thereto is: Substitute the minimum pitch ratio of the variable pitch propeller at each blade angle when the thrust is maximum and the corresponding propeller thrust coefficient into the relationship between propeller thrust, propeller thrust coefficient and pitch ratio to obtain the target propeller thrust of the variable pitch propeller at each blade angle; Obtain the maximum propeller thrust among the target propeller thrusts of the variable pitch propeller at all blade angles; The blade angle corresponding to the maximum propeller thrust is taken as the optimal blade angle.

[0018] An optimal blade angle simulation system for a variable pitch propeller aircraft during a taxiing takeoff phase, comprising: A parameter relationship module is used to obtain a relationship between propeller thrust, propeller thrust coefficient and pitch ratio according to a relationship between propeller thrust and propeller speed at a certain moment in the aircraft's rolling takeoff phase, and a relationship between incoming flow speed, propeller speed and pitch ratio; A maximum speed determination module, used to determine the maximum speed of the propeller according to the maximum speed within the engine envelope; The minimum pitch ratio module is used to obtain the minimum pitch ratio of the variable pitch propeller at each blade angle when the thrust is maximum according to the maximum propeller speed and the relationship between the incoming flow speed, the propeller speed and the pitch ratio; The optimal blade angle module is used to obtain the propeller thrust coefficient corresponding to each minimum pitch ratio; and obtain the optimal blade angle when the propeller thrust is maximum according to the minimum pitch ratio and the propeller thrust coefficient corresponding to it.

[0019] The beneficial effects of the present invention are: The present invention obtains a relationship between propeller thrust, propeller thrust coefficient and advance ratio according to a relationship between propeller thrust and propeller rotation speed at a certain moment in the taxiing and taking-off stage of an aircraft, and a relationship between incoming flow speed, propeller rotation speed and advance ratio; determines the maximum propeller rotation speed according to the maximum rotation speed in the engine envelope; obtains the minimum advance ratio of a variable pitch propeller at each blade angle when the thrust is maximum according to the maximum propeller rotation speed and the relationship between incoming flow speed, propeller rotation speed and advance ratio; finally, obtains an optimal blade angle when the propeller thrust is maximum according to the minimum advance ratio and the propeller thrust coefficient corresponding thereto, that is, the present invention realizes the design of the optimal blade angle of the variable pitch propeller of the aircraft in the taxiing and taking-off stage, thereby ensuring that the aircraft outputs the maximum thrust at every moment in the taxiing and taking-off stage. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 The present invention is a flow chart of an embodiment of a method for simulating an optimal blade angle of a variable pitch propeller aircraft during the rolling takeoff phase. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] An embodiment of a method and system for simulating the optimal blade angle of a variable pitch propeller aircraft during a rolling takeoff phase of the present invention is as follows: Figure 1 As shown, including: Step 1: According to the relationship between the propeller thrust and the propeller speed at a certain moment in the aircraft's rolling takeoff phase, and the relationship between the incoming flow velocity, the propeller speed and the pitch ratio, the relationship between the propeller thrust, the propeller thrust coefficient and the pitch ratio is obtained.

[0024] Step 11: The relationship between propeller thrust and propeller speed is:

[0025] In the formula, Indicates propeller thrust; represents the propeller thrust coefficient; Indicates propeller speed; Indicates the propeller diameter; Indicates the air density at the takeoff altitude.

[0026] Step 12: The steps for obtaining the relationship between the incoming flow velocity, the propeller speed and the pitch ratio are as follows: Establish the incoming flow velocity set at different times during the rolling takeoff phase of the variable pitch propeller aircraft, and take The speed of the aircraft flow at time :Then the incoming flow velocity set ;Establish The relationship between propeller speed and pitch ratio at the instantaneous incoming flow speed is:

[0027] In the formula, Indicates the distance ratio; Indicates the propeller diameter; Indicates propeller speed; Indicates the incoming flow velocity.

[0028] Step 13: The steps of obtaining the relationship between propeller thrust, propeller thrust coefficient and pitch ratio are as follows: According to the formulas in steps 11 and 12, the relationship between propeller thrust, propeller thrust coefficient and pitch ratio is:

[0029] According to the variable pitch propeller, the incoming flow speed is kept stable at this moment, so the incoming flow speed Basically unchanged, it can be considered is a constant, and the constant is represented by c. Then the relationship between the propeller thrust, propeller thrust coefficient and pitch ratio is:

[0030] In the formula, Indicates propeller thrust; Indicates the distance ratio; represents the propeller thrust coefficient; Indicates the propeller diameter; Indicates propeller speed; Indicates the air density at the take-off altitude; Indicates the incoming flow velocity.

[0031] Step 2: Determine the maximum propeller speed based on the maximum speed within the engine envelope; the specific expression of the maximum propeller speed is:

[0032] In the formula, Indicates the maximum propeller speed; Indicates the maximum speed within the engine envelope; Indicates the reduction ratio between the propeller and the engine.

[0033] Step 3: According to the maximum propeller speed, and the relationship between the incoming flow velocity, the propeller speed and the pitch ratio, the minimum pitch ratio of the variable pitch propeller at each blade angle when the thrust is maximum is obtained.

[0034] Specifically, according to the formula Know that in When the maximum value is taken, Need to be as small as possible, and according to the formula , the propeller speed should take the maximum value, so when the thrust of the variable pitch propeller is the maximum, the corresponding advance ratio is the minimum advance ratio.

[0035] Step 4: Obtain the propeller thrust coefficient corresponding to each minimum pitch ratio; and obtain the optimal blade angle when the propeller thrust is maximum according to the minimum pitch ratio and the propeller thrust coefficient corresponding to the minimum pitch ratio.

[0036] Step 41: The step of obtaining the propeller thrust coefficient corresponding to each minimum pitch ratio is: Establish a set of blade angle variation intervals for variable pitch propeller aircraft: ; Wind tunnel experiments are conducted on variable pitch propellers with different blade angles in the blade angle variation range under the minimum pitch ratio to obtain the propeller thrust coefficient corresponding to each minimum pitch ratio. That is, according to the propeller characteristics, the propeller thrust coefficient It changes with the distance ratio. The value of is obtained through wind tunnel tests. Assume that a set of thrust coefficients at the minimum pitch ratio of the variable pitch propeller at each blade angle is obtained in the wind tunnel test. The set of minimum pitch ratios is , then the set of thrust coefficients .

[0037] Step 42, the step of obtaining the optimal blade angle when the propeller thrust is maximum according to the minimum pitch ratio and the propeller thrust coefficient corresponding thereto is: Substitute the minimum pitch ratio of the variable pitch propeller at each blade angle when the thrust is maximum and its corresponding propeller thrust coefficient into the relationship between propeller thrust, propeller thrust coefficient and pitch ratio to obtain the target propeller thrust of the variable pitch propeller at each blade angle; obtain the maximum propeller thrust among the target propeller thrusts of the variable pitch propeller at all blade angles; and take the blade angle corresponding to the maximum propeller thrust as the optimal blade angle. That is, by the formula It can be seen that When is a constant, Value The larger the value, the greater the propeller thrust. Therefore, ; Substitute the minimum pitch ratio of the variable pitch propeller at each blade angle at maximum thrust and its corresponding propeller thrust coefficient into the formula , to obtain Collection ,exist Found in the collection The maximum value of , Corresponding blade angle That is, The optimal blade angle of the propeller at that moment.

[0038] Finally, the current incoming flow speed The next moment's incoming flow speed Repeat the above calculation process as input to get By analogy, the maximum thrust and optimal blade angle of the variable pitch propeller at any time during the entire takeoff run can be calculated.

[0039] The invention discloses an optimal blade angle simulation system for a variable pitch propeller aircraft in a taxiing and taking-off stage, comprising: a parameter relationship module, a maximum speed determination module, a minimum pitch ratio module and an optimal blade angle module, wherein the parameter relationship module is used for obtaining a relationship between propeller thrust, propeller thrust coefficient and pitch ratio according to a relationship between propeller thrust and propeller speed at a certain moment in the taxiing and taking-off stage of the aircraft, and a relationship between incoming flow velocity, propeller speed and pitch ratio; the maximum speed determination module is used for determining a maximum propeller speed according to a maximum speed within an engine envelope; the minimum pitch ratio module is used for obtaining a minimum pitch ratio of a variable pitch propeller at a maximum thrust under each blade angle according to a maximum propeller speed and a relationship between incoming flow velocity, propeller speed and pitch ratio; the optimal blade angle module is used for obtaining a propeller thrust coefficient corresponding to each minimum pitch ratio; and the optimal blade angle when the propeller thrust is maximum is obtained according to the minimum pitch ratio and the propeller thrust coefficient corresponding thereto.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for simulating the optimal blade angle of a variable pitch propeller aircraft during the rolling takeoff phase, characterized in that: include: According to the relationship between the propeller thrust and the propeller speed at a certain moment in the aircraft's rolling takeoff phase, and the relationship between the incoming flow speed, the propeller speed and the pitch ratio, the relationship between the propeller thrust, the propeller thrust coefficient and the pitch ratio is obtained; Determine the maximum propeller speed based on the maximum speed within the engine envelope; According to the maximum propeller speed, and the relationship between the incoming flow speed, propeller speed and pitch ratio, the minimum pitch ratio of the variable pitch propeller at each blade angle when the thrust is maximum is obtained; Obtain the propeller thrust coefficient corresponding to each minimum pitch ratio; The optimal blade angle when the propeller thrust is maximum is obtained according to the minimum pitch ratio and its corresponding propeller thrust coefficient.

2. The optimal blade angle simulation method for a variable pitch propeller aircraft during the rolling takeoff phase according to claim 1 is characterized in that: The relationship between propeller thrust and propeller speed is: In the formula, represents propeller thrust; represents the propeller thrust coefficient; Indicates propeller speed; Indicates the propeller diameter; Indicates the air density at the takeoff altitude.

3. The optimal blade angle simulation method for a variable pitch propeller aircraft during the rolling takeoff phase according to claim 1 is characterized in that: The relationship between the incoming flow velocity, propeller speed and pitch ratio is: In the formula, Indicates the distance ratio; Indicates the propeller diameter; Indicates propeller speed; Indicates the incoming flow velocity.

4. The optimal blade angle simulation method for a variable pitch propeller aircraft during a rolling takeoff phase according to claim 1, characterized in that: The relationship between propeller thrust, propeller thrust coefficient and pitch ratio is: In the formula, represents propeller thrust; Indicates the distance ratio; represents the propeller thrust coefficient; Indicates the propeller diameter; Indicates propeller speed; Indicates the air density at the take-off altitude; Indicates the incoming flow velocity.

5. The optimal blade angle simulation method for a variable pitch propeller aircraft during the rolling takeoff phase according to claim 1, characterized in that: Based on the maximum speed within the engine envelope, the steps to determine the maximum propeller speed are: In the formula, Indicates the maximum propeller speed; Indicates the maximum speed within the engine envelope; Indicates the reduction ratio between the propeller and the engine.

6. The optimal blade angle simulation method for a variable pitch propeller aircraft during the rolling takeoff phase according to claim 1, characterized in that: The steps to obtain the propeller thrust coefficient corresponding to each minimum pitch ratio are: Wind tunnel tests were carried out on variable pitch propellers with different blade angles at minimum pitch ratios, and the propeller thrust coefficient corresponding to each minimum pitch ratio was obtained.

7. The optimal blade angle simulation method for a variable pitch propeller aircraft during the rolling takeoff phase according to claim 1, characterized in that: The steps to obtain the optimal blade angle when the propeller thrust is maximum according to the minimum pitch ratio and its corresponding propeller thrust coefficient are as follows: Substitute the minimum pitch ratio of the variable pitch propeller at each blade angle when the thrust is maximum and the corresponding propeller thrust coefficient into the relationship between propeller thrust, propeller thrust coefficient and pitch ratio to obtain the target propeller thrust of the variable pitch propeller at each blade angle; Obtain the maximum propeller thrust among the target propeller thrusts of the variable pitch propeller at all blade angles; The blade angle corresponding to the maximum propeller thrust is taken as the optimal blade angle.

8. An optimal blade angle simulation system for a variable pitch propeller aircraft during the rolling takeoff phase, characterized in that: include: A parameter relationship module is used to obtain a relationship between propeller thrust, propeller thrust coefficient and pitch ratio according to a relationship between propeller thrust and propeller speed at a certain moment in the aircraft's rolling takeoff phase, and a relationship between incoming flow speed, propeller speed and pitch ratio; A maximum speed determination module, used to determine the maximum speed of the propeller according to the maximum speed within the engine envelope; The minimum pitch ratio module is used to obtain the minimum pitch ratio of the variable pitch propeller at each blade angle when the thrust is maximum according to the maximum propeller speed and the relationship between the incoming flow speed, the propeller speed and the pitch ratio; The optimal blade angle module is used to obtain the propeller thrust coefficient corresponding to each minimum pitch ratio; and obtain the optimal blade angle when the propeller thrust is maximum according to the minimum pitch ratio and the propeller thrust coefficient corresponding to it.

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