CN104142694A - Micro-flow control device of multilayer hole plate structure - Google Patents

Abstract

The invention relates to a micro-flow control device of a multilayer hole plate structure. The micro-flow control device comprises connector assemblies (1), hole plates (2) and end cover plates (3). Each hole plate (2) is in a disc shape, a plurality of small holes are machined in the surface of the disc, channels are formed between the small holes through etching, the end cover plates (3) are in disc shapes, small holes are formed in the centers of the discs, the two end cover plates (3) are welded to the two sides of the discs of the hole plates (2), the center holes of the end cover plates (3) are communicated with the small holes in the centers of the hole plates (2), the small holes in the hole plates (2) are connected in series through the etched channels from the small hole in the center, and the small holes are finally led to the small hole in the center; the two connector assemblies (1) are connected with the two end cover plates (3) respectively.

Description

A kind of perforated plate structure micro-flow controlling device

Technical field

The invention belongs to spacecraft spacemarching field, particularly a kind of perforated plate structure micro-flow controlling device, is applicable to spacecraft electric propulsion storage for the subsystem high-precision fine adjustment of xenon micrometeor and control.

Background technology

DFH-3B satellite platform adopts electric propulsion subsystem to carry out the space tasks such as position, north and south guarantor and momenttum wheel unloading, with respect to conventional chemical propulsion system, electric propulsion system has proposed propellant micrometeor high precision demand for control, and its flow is generally mg/s magnitude, and control accuracy is ± 3%.

Conventional flow control means are mainly orifice restriction at present, and for the flow control level of this mg/s level of electric propulsion system, its effective aperture is nm level level, and machining cannot realize on the one hand; The product that contains on the other hand this yardstick aperture is very responsive to fifth wheel, there is no at present effective fifth wheel control and safeguard procedures, and therefore conventional orifice restriction technology cannot be applicable to current spacecraft electric propulsion system.

Summary of the invention

Technology of the present invention is dealt with problems and is: overcome the deficiencies in the prior art, a kind of perforated plate structure micro-flow controlling device is provided.

Technical solution of the present invention is: a kind of perforated plate structure micro-flow controlling device, comprises adapter assembly, orifice plate and end casing; Described orifice plate is disc-shape, disc surfaces is processed some apertures, the diameter 50 μ m～100 μ m of aperture, between aperture, form passage by etching, the disc-shape of aperture is set centered by end casing, and two end casings are welded on the disk both sides of orifice plate, and the center pit of end casing is communicated with the aperture that is positioned at center on orifice plate, aperture on orifice plate starts to connect one by one by the passage of etching from middle aperture, aperture in the middle of finally leading to; Two adapter assemblies are connected with above-mentioned two end casings respectively.

The diameter 50 μ m～100 μ m of the aperture on described orifice plate,

In the time that the number of orifice plate is two, between two orifice plates and both sides are welding end cover plate respectively.

The central passage built-in filter that described adapter assembly communicates with end casing center pit.

The present invention compared with prior art beneficial effect is:

(1) the present invention proposes a kind of perforated plate structure micro-flow controlling device, this structure adopts machining process to realize, its latus rectum is generally in 50 μ m～100 μ m scopes, this has just reduced the sensitivity of product to fifth wheel, at unit with system-levelly all can use existing fifth wheel control measure to protect, and this micro-flow controlling device does not have movable members, not there is not the possibility of " automatic pollution ".

(2) perforated plate structure micro-flow controlling device of the present invention is said and is belonged to " single hole " structure from the angle of MEDIA FLOW path, but be different from " single hole " structure of ordinary meaning, it is the sandwich construction that is integrated with a large amount of passages and hole on very little area, by welding, channel enclosed is got up, form the very large medium channel of flow resistance, actuating medium flows through that this sandwich construction forms complexity but when not bery narrow fluid passage, its speed recurs variation, energy constantly reduces, thereby reach throttling object, delivery rate finally meets pre-provisioning request.

(3) the equal built-in filter in its entry and exit of perforated plate structure micro-flow controlling device of the present invention, can effectively prevent that external fifth wheel from entering this device inside, no-movable part in this device indoor design simultaneously, can not occur, due to product " automatic pollution " problem that the friction phenomenon between movable part brings, to be applicable to being very much applied to the field of high precision tiny flow quantity controller demand.

Brief description of the drawings

Fig. 1 is apparatus of the present invention schematic diagram;

Fig. 2 is orifice plate schematic diagram of the present invention;

Fig. 3 is end casing schematic diagram of the present invention;

Fig. 4 is adapter assembly schematic diagram of the present invention;

Fig. 5 is computational grid loop schematic diagram;

Fig. 6 is cavity volume-resistance element fluidal texture figure.

Embodiment

Below in conjunction with accompanying drawing, the present invention is elaborated, as shown in Figure 1, a kind of perforated plate structure of the present invention micro-flow controlling device, comprises adapter assembly 1, orifice plate 2 and end casing 3; As shown in Figure 2, it is disc-shape that described orifice plate 2 adopts corrosion resistant plate, and disc surfaces is processed some apertures by the method for laser boring, the diameter 50 μ m～100 μ m of aperture, deviation ± 0.2 μ m; Between aperture, form passage by etching mode, as shown in Figure 3, end casing 3 is processed into identical with orifice plate 2 external diameters discoid equally by corrosion resistant plate, center spiles, the mode of two end casing 3 Diffusion Welding is welded on the disk both sides of orifice plate 2, the center pit of end casing 3 is communicated with the aperture that is positioned at center on orifice plate 2, and the aperture on orifice plate 2 starts to connect one by one by the passage of etching from middle aperture, aperture in the middle of finally leading to; As shown in Figure 4, adapter assembly 1 adopts stainless steel bar processing, and built-in filter, is connected with end casing 3 in the mode of electron beam welding, and two adapter assemblies 1 are connected with above-mentioned two end casings 3 respectively.

In the time that the quantity of orifice plate 2 is 2, adopt connected mode as shown in Figure 1, between two orifice plates 2 and both sides are welding end cover plate 3 respectively, the final layer AND DEWATERING FOR ORIFICE STRUCTURE micro-flow controlling device that forms.

Traffic requirement as for the quantity Main Basis micro-flow controlling device of aperture on orifice plate 2 is determined.Mainly can adopt following step to calculate:

First, the flow process of gas in runner can be considered flow through from import to the outlet process of resistance element (throttle orifice) and capacitive element (cavity volume) of a series of series connection of gas.Therefore, can be by the gas flow network loop being formed by throttle orifice (aperture in corresponding orifice plate 2) and cavity volume (etched channels in corresponding orifice plate 2 between two adjacent segments discharge orifices) shown in mobile Fig. 5 of being reduced to of medium in runner shown in Fig. 2.So just, can calculate the pressure reduction of labyrinth flow-path and the relation of flow is flow resistance characteristic by the discharge relation formula of each well known elements.

Wherein, the mathematical feature model of each flow element is as follows respectively:

A. throttle orifice mass flow calculation formula

$G=C_{d}A\sqrt{k}\frac{P_u}{\sqrt{{\mathrm{RT}}_u}}\mathrm{\φ}\left(\frac{P_d}{P_u}\right)$

Wherein:

$\mathrm{\φ}\left(\frac{P_d}{P_u}\right)=\left\{\begin{array}{cc}\sqrt{\left(\frac{2}{k-1}\right)[{\left(\frac{P_d}{P_u}\right)}^{\frac{2}{k}}-{\left(\frac{P_d}{P_u}\right)}^{\frac{k+1}{k}}]}& \left(\frac{P_d}{P_u}\right)>P_{\mathrm{cr}}\\ \sqrt{{\left(\frac{2}{k+1}\right)}^{\frac{k+1}{k-1}}}& \left(\frac{P_d}{P_u}\right)\≤P_{\mathrm{cr}}\end{array}\right.$

$P_{\mathrm{cr}}={\left(\frac{2}{k+1}\right)}^{\frac{k}{k-1}}$

In formula, G is mass rate, P _u, P _dbe respectively the gaseous tension of throttle orifice upstream and downstream, P _crfor critical pressure ratio, C _dfor coefficient of flow, A is throttle hole area, T _ufor upstream gas temperature, R is gas law constant, and k is gas adiabatic exponent.

B. the thermodynamical model of cavity volume

Gaseous state changes obedience the Ideal-Gas Equation herein, thereby has

$\left[\begin{array}{cc}V\·{\left(\frac{\∂\mathrm{\ρ}}{\∂p}\right)}_T& V\·{\left(\frac{\∂\mathrm{\ρ}}{\∂T}\right)}_p\\ m\·{\left(\frac{\∂h}{\∂p}\right)}_T-V& m\·{\left(\frac{\∂h}{\∂T}\right)}_p\end{array}\right]\left[\begin{array}{c}\frac{\mathrm{dp}}{\mathrm{dt}}\\ \frac{\mathrm{dT}}{\mathrm{dt}}\end{array}\right]=\left[\begin{array}{c}\mathrm{\Σ}\frac{{\mathrm{dm}}_i}{\mathrm{dt}}-\mathrm{\ρ}\·\frac{\mathrm{dV}}{\mathrm{dt}}\\ \mathrm{\Σ}\frac{{\mathrm{dm}}_i}{\mathrm{dt}}{\·h}_i-\mathrm{\Σ}\frac{{\mathrm{dm}}_i}{\mathrm{dt}}\·h+\mathrm{\δQ}\end{array}\right]$

Wherein, p is pressure, and V is volume, and T is temperature, the density that ρ is gas, and m is the quality of holding intracavity gas, m _ifor flowing into or flow out the quality (i=1 represents to flow into, and i=-1 represents to flow out) of cavity volume, h is the total enthalpy that holds intracavity gas, h _ifor flowing into or flow out the total enthalpy of cavity volume, Q is the heat exchanging with the external world.

Method of calculating flux brief introduction is as follows:

Because computational grid is made up of a series of resistance elements and capacitive element (cavity volume), can not be directly according to the gas parameter of given network loop import and export, obtain the gaseous tension in cavity volume and pass through the gas flow in flow network loop, therefore must adopt solution by iterative method.

According to law of conservation of mass, be identical by the flow of each throttle orifice, that is flow into and flow out the mass rate of each cavity volume and should meet flow equilibrium relation, therefore the algorithm of the flow equilibrium residual error correction pressure of employing cavity volume carries out iterative computation:

(1) first suppose the pressure initial value in each cavity volume;

(2) calculate the mass rate of each throttle orifice according to original pressure;

(3) obtain and flow into and the mass rate residual error that flows out each cavity volume;

(4) according to residual error, the pressure distribution of each cavity volume is revised, iterative computation until the flow residual error of last each element in allowed limits.

The pressure correction computing method of each cavity volume are as follows:

As shown in Figure 6, there is cavity volume i-1, i, i+1, the flow that flows into cavity volume i from cavity volume i-1 is designated as G1, and the flow flowing out from cavity volume i is designated as G2.For given labyrinth flow-path, its geometric parameter is certain, and the mass rate of each throttle orifice depends on and the pressure of two cavity volumes that are connected with this element, can draw thus:

G ₁＝G ₁(p _i-1，p _i) (1)

G ₂＝G ₂(p _i，p _i+1) (2)

Getting differential obtains: ${\mathrm{dG}}_1=\frac{{\∂G}_1}{{\∂p}_{i-1}}{\mathrm{dp}}_{i-1}+\frac{{\∂G}_1}{{\∂p}_i}\mathrm{dp}---\left(3\right)$

${\mathrm{dG}}_2=\frac{{\∂G}_2}{{\∂p}_i}{\mathrm{dp}}_i+\frac{{\∂G}_2}{{\∂p}_{i+1}}{\mathrm{dp}}_{i+1}---\left(4\right)$

$d(G_1-G_2)=\frac{{\∂G}_1}{{\∂p}_{i-1}}{\mathrm{dp}}_{i-1}+(\frac{{\∂G}_1}{{\∂p}_i}-\frac{{\∂G}_2}{{\∂p}_i}){\mathrm{dp}}_i-\frac{{\∂G}_2}{{\∂p}_{i+1}}{\mathrm{dp}}_{i+1}---\left(5\right)$

Make dG _i=-d (G ₁-G ₂) (6)

So have $\frac{{\∂G}_1}{{\∂p}_{i-1}}{\mathrm{dp}}_{i-1}+(\frac{{\∂G}_1}{{\∂p}_i}-\frac{{\∂G}_2}{{\∂p}_i}){\mathrm{dp}}_i-\frac{{\∂G}_2}{{\∂p}_{i+1}}{\mathrm{dp}}_{i+1}=-{\mathrm{dG}}_i---\left(7\right)$

Have (7) formula to set up to each cavity volume in labyrinth flow-path, by the flow deviation dGi of known cavity volume, the system of equations that simultaneous solution is made up of formula (7), just can obtain the required pressure correction value dpi of each cavity volume.In formula (7), each resistance element flow all adopts numerical evaluation to try to achieve to the partial derivative of cavity volume pressure, give a little variation to the flow of each resistance element, obtain the change value of pressure of two cavity volumes adjacent with this element, the business of the fluctuations in discharge value of this resistance element and the changing value of cavity volume pressure is the local derviation numerical value of corresponding flow to cavity volume pressure.

Secondly in the time adopting said method to carry out flow resistance calculating, need do following hypothesis:

Each chamber pressure is uniformly distributed;

The temperature of each chamber equates.

Adopt above-mentioned process of iteration to get final product to obtain the quantitative relationship between the perforated plate structure parameter such as outflow and aperture, hole count.

The unspecified part of the present invention belongs to general knowledge as well known to those skilled in the art.

Claims (4)

1. a perforated plate structure micro-flow controlling device, is characterized in that: comprise adapter assembly (1), orifice plate (2) and end casing (3); Described orifice plate (2) is disc-shape, disc surfaces is processed some apertures, between aperture, form passage by etching, the disc-shape of aperture is set centered by end casing (3), two end casings (3) are welded on the disk both sides of orifice plate (2), the center pit of end casing (3) is communicated with the aperture that is positioned at center on orifice plate (2), aperture on orifice plate (2) starts to connect one by one by the passage of etching from middle aperture, aperture in the middle of finally leading to; Two adapter assemblies (1) are connected with above-mentioned two end casings (3) respectively.

2. a kind of perforated plate structure micro-flow controlling device according to claim 1, is characterized in that: the diameter 50 μ m～100 μ m of the aperture on described orifice plate (2).

3. a kind of perforated plate structure micro-flow controlling device according to claim 1, is characterized in that: in the time that the number of orifice plate (2) is two, between two orifice plates and both sides are welding end cover plate (3) respectively.

4. according to a kind of perforated plate structure micro-flow controlling device described in claim 1 or 3, it is characterized in that: the central passage built-in filter that described adapter assembly (1) communicates with end casing (3) center pit.