CN100441950C - Back pressure adaptive constant-flow nozzle - Google Patents

Abstract

A back-pressure self-adaptive constant flow nozzle for a liquid fuel injection system, the sleeve (1) is provided with a central rod (10), the rear of the central rod (10) is a cylindrical body (4) and the front It is a cone (8), the larger end of the cone (8) is located on the side of the nozzle outlet (9), the center rod (10) is covered with a piston (2) and the inner cavity of the piston (2) is in line with the The front end of the annulus (7) formed between the cones (8) communicates with the nozzle outlet (9) and its rear end communicates with the front end of the channel (6) in the cylindrical body. After the channel (6) The end is a fuel inlet (5), and a spring (3) is arranged between the rear end of the piston (2) and the rear end of the sleeve (1). Compared with existing nozzles, it can automatically adapt to back pressure changes within a certain range without external energy drive, keep the flow constant, and has simple structure and reliable performance. It can be widely used in energy, power, heating, aerospace propulsion, etc. Note system.

Description

A Back Pressure Adaptive Constant Flow Nozzle

technical field

The invention relates to a nozzle used for liquid fuel injection systems such as kerosene, diesel oil, gasoline, residual oil, etc., and can be applied to injection systems such as energy, power, heating, and aerospace propulsion.

Background technique

The main function of the nozzle is to introduce liquid fuel into the combustion chamber, control its flow, and break the liquid into small droplets. In the past, when designing nozzles, people only cared about its atomization performance, and various types of nozzles were developed from the atomization method. Several types currently commonly used are: straight-line nozzles (including jet nozzles, flat nozzles, diesel engine nozzles, fan-shaped hole nozzles, etc.), centrifugal nozzles, two-fluid nozzles (divided into gas-assisted nozzles and gas-blown nozzles) , rotary nozzles and other forms of nozzles (including supersonic nozzles, sonic nozzles, electric nozzles, etc.).

The common feature of the above nozzles is that the design assumes that the combustion chamber pressure is known and constant, and the fuel flow rate is determined by the tank pressure and the throttle area. However, in actual work, the pressure of the combustion chamber is not always equal to the rated pressure, but fluctuates within a certain range, especially when the system starts, changes to working conditions and shuts down, the pressure of the combustion chamber is far from the rated value, and the flow characteristics of ordinary nozzles cannot ensure.

Contents of the invention

The technical problem to be solved by the present invention is to propose a back pressure self-adaptive constant flow nozzle, which can be driven within a certain range without the need for external energy drive, in view of the defect that the flow characteristics of the existing nozzles cannot be guaranteed when the back pressure deviates from the rated value. Automatically adapt to the change of back pressure, keep the flow constant, and have simple structure and reliable performance.

The technical solution of the present invention is that the back pressure adaptive constant flow nozzle includes a sleeve, and its structural feature is that a central rod is arranged in the sleeve, and the rear part of the central rod is a cylindrical body and the front part is a conical body , the larger end of the cone is located on the side of the nozzle outlet, the center rod is fitted with a piston and the front end of the ring gap formed between the piston cavity and the cone communicates with the nozzle outlet and its rear end It communicates with the front end of the channel in the cylindrical body, the rear end of the channel is a fuel inlet, and a spring is installed between the rear end of the piston and the rear end of the sleeve.

The present invention is further described below.

Referring to Fig. 1, the present invention comprises sleeve 1, and its structural characteristic is, described sleeve 1 is provided with central rod 10, and this central rod 10 rear part is cylindrical body 4 and front part is conical body 8, and described conical body 8, the larger end is located on the side of the nozzle outlet 9, the central rod 10 is fitted with a piston 2 and the front end of the ring gap 7 formed between the inner cavity of the piston 2 and the cone 8 communicates with the nozzle outlet 9. Its rear end communicates with the front end of the channel 6 in the cylindrical body, the rear end of the channel 6 is a fuel inlet 5, and a spring 3 is installed between the rear end of the piston 2 and the rear end of the sleeve 1 .

The technical principle of the nozzle of the present invention is that the liquid fuel enters the passage 6 of the central rod 10 from the fuel inlet 5 according to the direction of the arrow on the right side of Fig. Annular gap) 7 is injected, and the flow G is determined by the following formula:

$\mathrm{<span\; class="notranslate">\; G</span>}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}\mathrm{<span\; class="notranslate">\; A</span>}\sqrt{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&rho;</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; p</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; p</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

In the formula: C _d is the flow coefficient; A is the throttle area; ρ is the liquid fuel density; p ₀ is the total head pressure of the liquid fuel; p is the outlet back pressure.

Piston 2 and spring 3 components are used as sensitive elements to sense the change of back pressure. Through the force balance between spring 3 and back pressure, the amount of back pressure change is recorded by the elastic compression of spring 3. At the same time, the effect is directly transmitted to piston 2 of the actuator, and piston 2 is relatively The change of the position of the central rod 10 of the adjustment mechanism leads to the change of the gap between the two, that is, the change of the throttle area of the nozzle, so that the flow rate G in formula (1) is always equal to the design value.

It can be seen from the above that the present invention is a back pressure self-adaptive constant flow nozzle. Compared with the existing nozzles, it can automatically adapt to the change of back pressure within a certain range and keep the flow constant without the need for external energy drive, and has a simple structure and excellent performance. It is reliable and can be widely used in injection systems such as energy, power, heating, and aerospace propulsion.

Description of drawings

Fig. 1 is a schematic structural view of an embodiment of the present invention.

In the picture:

1-sleeve, 2-piston, 3-spring, 4-cylindrical body, 5-fuel inlet, 6-channel, 7-annulus, 8-cone, 9-nozzle outlet, 10-central rod.

Detailed ways

According to the figure and the back pressure adaptive constant flow nozzle of the above structure, each component is made of homogeneous metal material, which is applied in the water reaction metal fuel engine, and water is introduced into the combustion chamber by using the nozzle; the actual use shows that when the combustion chamber pressure When changing between 0.2MPa-0.55MPa, the water flow flowing through the back pressure adaptive constant flow nozzle of the present invention is constant at around 0.035kg/s, with a maximum error of 1.7%, which effectively solves the problem of water-reactive metal fuel engines. When the working condition is changed, the water flow is too large to extinguish the flame.

Claims (1)

1. A back pressure adaptive constant flow nozzle, comprising a sleeve (1), characterized in that a central rod (10) is arranged in the sleeve (1), and the rear part of the central rod (10) is a cylindrical body (4) and the front part is a cone (8), the larger end of the cone (8) is located on the nozzle outlet (9) side, the center rod (10) is sleeved with a piston (2) and the piston ( 2) The front end of the annulus (7) formed between the inner cavity and the cone (8) communicates with the nozzle outlet (9) and its rear end communicates with the front end of the channel (6) in the cylindrical body, The rear end of the passage (6) is a fuel inlet (5), and a spring (3) is arranged between the rear end of the piston (2) and the rear end of the sleeve (1).

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