CN102507078A - Precision measuring system and method for conveying pipe flow resistance - Google Patents

Abstract

The invention belongs to rocket boost conveying system, and particularly relates to a precision measuring method for flow resistance of real propellant flowing through a conveying pipe, which aims to precisely measure actual flow resistance value of the conveying pipe under given propellant flow rate. The measuring system includes a propellant storage tank, wherein three branches are externally connected to the storage tank; the two branches are storage tank outflow branches; the propellant is sequentially connected with a test piece of the conveying pipe through a gear pump, a flow rate, a ball valve and a stainless steel corrugated pipe; the third branch is a propellant back flow path and includes a ball valve; a differential pressure gage is arranged between two conveying pipe inlets; a differential pressure gage is arranged between any conveying pipe inlet and conveying pipe outlet; and two ends of the differential pressure gages are connected with a measuring terminal through a needle valve. The two groups of differential pressure gages are used for measuring differential pressure, and the gear pump achieves flowrate variable frequency adjustment. The precision measuring system and method can precisely measure the actual flow resistance value of the conveying pipe, so as to check the design reasonableness of the conveying pipe.

Description

A system and method for accurately measuring the flow resistance of a conveying pipe

technical field

The invention belongs to a rocket pressurized conveying system, in particular to a method for accurately measuring the flow resistance of a real propellant flowing through a conveying pipe.

Background technique

The oxygen and fuel propellant of the new rocket each have two storage tanks, which are arranged symmetrically. This structural scheme is obviously different from the current model. According to the traditional delivery pipe sampling method, it is difficult to achieve a symmetrical arrangement of the delivery pipes of the symmetrical double tanks, which leads to inconsistent flow resistances of the two branch pipes of the oxygen and fuel delivery pipes. For flow resistance balancing, this model uses a delivery tube with adjustable flow resistance. In order to check the design flow resistance value of the delivery pipe, it is necessary to accurately measure the actual flow resistance value of the delivery pipe in the ground test.

According to requirements, the flow resistance values of the two branch pipes of the conveying pipe must be highly close, and the flow resistance difference between the two branch pipes is within ±25pa. According to the traditional flow resistance measurement technology, the flow resistance of the real propellant flowing through the delivery pipe is measured, and the measurement accuracy cannot meet the requirements of this model. Therefore, it is necessary to design a new method for measuring the flow resistance of real propellant flowing through the delivery pipe.

Contents of the invention

The purpose of the invention is to accurately measure the actual flow resistance value of the delivery pipe under a given propellant flow rate, and to provide an accurate measurement method for the flow resistance of the delivery pipe.

The technical scheme adopted in the present invention is:

An accurate measurement system for the flow resistance of a conveying pipe, including a propellant storage tank, and three branches are connected outside the storage tank, two of which are outflow branches of the storage tank, and the propellant passes through a gear pump, a flow meter, and a ball valve in sequence 1. The stainless steel bellows is connected to the delivery pipe test piece, and the third branch is the propellant return flow path, including a ball valve; a differential pressure gauge is arranged between the inlets of the two delivery pipes, and a differential pressure gauge is arranged between any inlet of the delivery pipe and the outlet of the delivery pipe. A differential pressure gauge, the two ends of the differential pressure gauge are connected to the measuring port through a needle valve. Two sets of differential pressure gauges realize differential pressure measurement, and the gear pump realizes frequency conversion regulation of flow.

The above-mentioned accurate measurement system for the flow resistance of the delivery pipe also includes a horizontal test platform. The horizontal test platform uses a high-precision spirit level and a feeler gauge to adjust the level of the delivery pipe test piece, so that the two inlets of the delivery pipe are on the same level. The level gauge is used to measure the levelness of the inlet of the delivery pipe, and the height difference between the two inlets of the delivery pipe is obtained through the measured value of the levelness, and adjusted with a feeler gauge.

A method for accurately measuring the flow resistance of a delivery pipe, specifically comprising the following steps:

(a) Build an accurate measurement system for the flow resistance of the delivery pipe;

(b) Adjust the frequency of the gear pump and control the rotation rate of the pump until the specified flow rate of the test is achieved;

(c) Two high-precision differential pressure gauges, respectively measure the pressure difference Δp ₁ between the inlets of the two conveying pipes, and the pressure difference Δp ₂ between the inlet and the outlet. Through the differential pressure value measured by the high-precision differential pressure gauge, the actual flow resistance values between the two inlets of the delivery pipe test piece, and between an inlet and the outlet are obtained as Δp ₂ , Δp ₂ -Δp ₁ .

The method for accurately measuring the flow resistance of the delivery pipe as described above further includes the step of adjusting the height difference between the two inlets of the delivery pipe test piece between steps (b) and (c).

The beneficial effects of the present invention are:

1. The measurement method provided by the present invention is to use a propellant pumping delivery system to measure the flow resistance value of the real delivery pipe under a given propellant flow rate, to accurately measure the actual flow resistance value of the delivery pipe, and to check the delivery pipe The design is reasonable, and the measurement accuracy meets the model requirements.

2. Through the height-adjustable test platform, ensure that the two inlets of the delivery pipe are kept at the same height, avoid the influence of height difference on the measurement data, and ensure the accuracy of the measurement data.

Description of drawings

Fig. 1 is a schematic structural diagram of a system for accurately measuring the flow resistance of a delivery pipe provided by the present invention;

In the figure: 1. storage tank; 2. gear pump; 3. flow meter; 4. ball valve; 5. differential pressure gauge; 6. stainless steel bellows; Inlet, 10. Delivery pipe outlet.

Detailed ways

A method for accurately measuring the flow resistance of the delivery pipe provided by the present invention will be introduced below in conjunction with the accompanying drawings and embodiments:

As shown in Figure 1, an accurate measurement system for the flow resistance of a delivery pipe includes a propellant tank 1, and three branches are connected outside the tank 1, two of which are the outflow branches of the tank 1, and the propellant The delivery pipe test piece 8 is connected sequentially through the gear pump 2, the flow meter 3, the ball valve 4, and the stainless steel bellows 6. The third branch is the propellant return flow path, including a ball valve 4. A differential pressure gauge 5 is arranged between two conveying pipe inlets 9, a differential pressure gauge 5 is arranged between any conveying pipe inlet 9 and a conveying pipe outlet 10, and both ends of the differential pressure gauge 5 are connected to the measuring port through a needle valve 7. The two sets of differential pressure gauges 5 realize pressure difference measurement, and the gear pump 2 realizes flow frequency conversion regulation.

In addition, in order to eliminate the influence of the entrance height difference on the measurement accuracy, a horizontal test platform is added. The horizontal test platform uses a high-precision level ruler and a feeler gauge to adjust the level of the delivery pipe test piece 8, so that the two delivery pipe inlets 9 are on the same level. . The spirit level is used to measure the levelness of the delivery pipe inlet 9, and the height difference between the two delivery pipe inlets 9 is obtained through the levelness measurement value, and adjusted with a feeler gauge.

A method for accurately measuring the flow resistance of a delivery pipe, specifically comprising the following steps:

(1) Build an accurate measurement system for the flow resistance of the delivery pipe, and connect three branches outside the propellant storage tank 1, two of which are the outflow branches of the storage tank 1, and the propellant passes through the gear pump 2 and the flow meter in sequence 3. The ball valve 4 and the stainless steel bellows 6 are connected to the delivery pipe test piece 8, and the third branch is the propellant return flow path, including a ball valve 4. A differential pressure gauge 5 is arranged between two conveying pipe inlets 9, a differential pressure gauge 5 is arranged between any conveying pipe inlet 9 and a conveying pipe outlet 10, and both ends of the differential pressure gauge 5 are connected to the measuring port through a needle valve 7.

(2) The test piece of the conveying pipe is arranged on the test platform. Before the test, first adjust the level of the test platform, use a level to measure the height difference between the two entrances of the test piece, and then eliminate the height difference by selecting a suitable feeler gauge.

(3) During the flow resistance measurement process, the propellant flow rate flowing through the delivery pipe test piece 8 is required to be a fixed value, and the flow rate adjustment adopts the mutual control mode of the flow meter 3 and the gear pump 2 . After setting the frequency of the gear pump 2, turn on the gear pump 2, adjust the frequency of the gear pump 2 according to the flow rate displayed by the flow meter 3, and control the rotation rate of the pump until the specified flow rate of the test is achieved.

(4) Using two differential pressure gauges 5 , measure the pressure difference Δp ₁ between the inlets 9 of the two delivery pipes, and the pressure difference Δp ₂ between the inlet 9 and the outlet 10 of the delivery pipe. Through the differential pressure value measured by the differential pressure gauge 5 , the actual flow resistance values between two inlets of the delivery pipe test piece 8 , and between an inlet and an outlet are obtained as Δp ₂ , Δp ₂ −Δp ₁ , respectively.

The traditional method of measuring the flow resistance of the delivery pipe is to use a pressure sensor to measure the pressure value of a certain measuring point. The measurement accuracy of the traditional method cannot meet the technical requirements of the newly developed model. The measurement system uses two high-precision differential pressure gauges to measure the pressure difference between the two inlets of the delivery pipe, and the pressure difference between an inlet and the outlet. The actual flow resistance and flow resistance difference of the two branch pipes of the delivery pipe are calculated respectively by the pressure difference value measured by the high-precision differential pressure gauge. The measurement accuracy of the differential pressure gauge is 0.1%.

Claims (4)

1. An accurate measurement system for the flow resistance of a delivery pipe, comprising a storage tank (1) of propellant, three branches are connected outside the storage tank (1), two of which are outflow branches of the storage tank (1), The propellant passes through the gear pump (2), the flow meter (3), the ball valve (4), and the stainless steel bellows (6) to connect the delivery pipe test piece (8); the third branch is the propellant return flow path, including a ball valve (4); A differential pressure gauge (5) is arranged between two delivery pipe inlets (9), a differential pressure gauge (5) is arranged between any delivery pipe inlet (9) and a delivery pipe outlet (10), and the differential pressure The two ends of the meter (5) are connected to the measuring ports through the needle valve (7). 2. A kind of delivery pipe flow resistance accurate measurement system according to claim 1, it is characterized in that: described measurement system also comprises horizontal test platform, and horizontal test platform adjusts delivery pipe test by high-precision spirit level ruler, feeler gauge levelness of the piece (8), so that the two inlets (9) of the delivery pipe are on the same level; The height difference between them is adjusted with a feeler gauge. 3. A method for accurately measuring the flow resistance of a delivery pipe, specifically comprising the steps of: (a) Build an accurate measurement system for the flow resistance of the delivery pipe; (b) Adjust the frequency of the gear pump (2) and control the rotation rate of the pump until the specified flow rate of the test is achieved; (c) Two differential pressure gauges (5), respectively measure the pressure difference Δp ₁ between the inlets of two delivery pipes (9), and the pressure difference Δp between the inlet of a delivery pipe (9) and the outlet of the delivery pipe (10) ₂ ; through the differential pressure value measured by the differential pressure gauge (5), the actual flow resistance values between the two inlets of the delivery pipe test piece (8) and between an inlet and the outlet are respectively Δp ₂ , Δp ₂ -Δp ₁ . 4. A method for accurately measuring the flow resistance of a delivery pipe according to claim 3, characterized in that: between said steps (b) and (c), it also includes adjusting between the two inlets of the delivery pipe test piece (8). The height difference between the steps.

Images