RU2458289C2 - Electrostatic injector - Google Patents

Abstract

FIELD: ventilation.

SUBSTANCE: injector includes housing with inlet confuser, outlet and constant cross-section channel, discharge electrode, collecting electrode, which are connected to high-voltage DC source and installed in parallel planes perpendicular to longitudinal axis of constant cross-section channel. In addition, housing outlet is made in the form of outlet diffuser.

EFFECT: increasing the efficiency.

1 dwg

Description

The invention relates to the field of creating gas flows and can be used in ventilation and air conditioning systems in rooms.

Known electrostatic blowers according to the patents of the Russian Federation, IPC7 F24F 3/16: No. 2121115, 2172898, 2187762, 2304333, 2301377, 2343362, 2109220, 2202741, 2005962, 2181466, 2156169, 2313732, 2202741, 10851.

The closest technical solution is the supercharger described in the utility model patent of RF patent 10851, IPC: F24F 3/16, selected as a prototype.

This technical solution contains a housing with input and output. In the case, in its channel with a constant cylindrical section, on the input side there is a discharge needle electrode connected to the negative pole of the high-voltage direct current source, and on the output side there is a collecting electrode connected to the positive pole of the said current source. The inlet for the flow in the housing is made in the form of a confuser, which helps to reduce hydrodynamic losses.

The main disadvantage of the known devices is the low efficiency. Only 1 ÷ 2% of the supplied electric power is converted into mechanical energy of the generated gas stream. This is primarily due to the fact that the speed of gas ions, which in the known devices set the gas flow in motion, in the interelectrode space is very high (100 ÷ 200 m / s), while the velocity head created in the interelectrode space of the known devices allows reach flow rates of the order of 1 ÷ 3 m / s. Because of this speed difference, most of the electrical energy supplied to the electrodes is converted to heat.

However, in all known devices, productivity is determined by the flow rate in the interelectrode section, and this speed is determined by the velocity head of the flow, which the electrodes create when a high voltage is applied to them.

In order to increase the efficiency of these devices, it is necessary, in particular, to reduce hydraulic losses. To a first approximation, these losses are the sum of hydraulic losses due to the flow around the internal walls of the gas path and losses during the flow around discharge and collecting electrodes. Hydraulic losses can be minimized by organizing a smooth entrance in the form of a confuser and reducing clutter of the gas duct passage section with discharge and collecting electrodes. In this case, the hydrodynamic losses per unit length of the channel will be 2–3% of the velocity head in its narrowest section.

By reducing hydraulic losses, productivity can be increased by a few percent.

The objective of the invention is to increase the efficiency by several times.

The problem is solved in that in an electrostatic supercharger containing a housing with an inlet confuser, an output and a constant-cross-section channel, a discharge electrode collecting an electrode connected to a high-voltage direct current source and installed in parallel planes perpendicular to the longitudinal axis of the constant-cross-section channel, the housing output is made in type of output diffuser.

Figure 1 shows the design of the claimed supercharger, where:

1 - housing;

2 - input confuser;

3 - channel of constant cross section;

4 - discharge electrode;

5 - needles;

6 - collecting electrode;

7 - high-voltage direct current source;

8 - output diffuser.

The electrostatic supercharger contains a housing 1, an inlet diffuser 2, a constant cross-section channel 3, a discharge electrode 4 with needles 5, a collecting electrode 6, and the discharge 4 and collecting 6 electrodes are installed in the constant cross-section channel 3 in the housing 1 in planes parallel to each other and perpendicular the longitudinal axis of symmetry of the channel of constant cross section 3; and are electrically connected to a high-voltage source of direct current 7, and the output diffuser 8 with its small cross section is connected with the channel of constant cross section 3.

The proposed device operates as follows. Under the action of forces of high intensity of the electrostatic field, which is formed near conductive surfaces of large curvature (the tip of the needle 4), charged air particles (air ions) are formed, which rush at high speed to the collecting electrode 6, dragging the air with them. When this occurs in the air flow the total pressure increase ΔRo Po = Pst + ξ · V ^2/2, wherein:

RST - static pressure in the stream,

ξ is the density of air,

V is the flow rate.

If the flow rates are low (for air under normal conditions

V <100 m / s), then such flows can be considered incompressible and the total pressure in them remains. Since air enters the channel from the atmosphere, Po = Ra, where Ra is the atmospheric pressure. Let ΔР be the increase in total pressure during the passage of the interelectrode space, then

Ro = Ra + = ΔRo R'st. + Ξ · V ^'2/2,

where: R'st. and V ', respectively, the static pressure and speed in the output part of the channel after the collecting electrode. At the channel exit, the static pressure in the flow becomes equal to atmospheric Ra. Then the velocity of the outgoing stream Va can be found from the equation:

.? P = Pa + Pa + ξ · Va ^2/2 or

.

The value of ΔP is determined by the parameters of the electric current, which is formed by aero ions. Since with a constant geometry of the location of the electrodes and the magnitude of the supplied high voltage, a quite definite speed of aeroions and their concentration are established, and, therefore, a very definite value of the discharge current and electric power spent on its creation.

The force acting on the flow from the side of air ions is completely determined by their speed and concentration, then the increase in total pressure is determined in a first approximation only by the parameters of the electric discharge current.

Due to the fact that the rate of aero ions is significantly higher than the flow rate, the increase in total pressure will be almost constant with increasing flow rate over a fairly wide range (almost two to three times).

This means that the speed in the output section of the supercharger channel will not change if it is expanded or reduced, because it is determined only by the increase in total pressure ΔР.

In the case of expansion of the output section Fa (output diffuser 8) (see FIG. 1), the velocity in the constant part of channel 3 with the area Fm will increase due to the property of continuous flows. Moreover, the velocities will be related by the continuity equation Vm · Fm. = Va · Fa. That is, the greater Fa / Fm, the greater the speed through the channel in its constant cross section 3, and hence the gas flow rate, i.e. supercharger efficiency increases.

A tapering inlet (inlet confuser 2) is necessary in order to avoid a sharp acceleration of atmospheric air entering the constant cross-section channel 3, and to avoid the occurrence of a tear-off flow in which the loss of full pressure will occur.

Thus, the introduction of an expanding output part (output diffuser 8) can significantly increase the efficiency of the proposed electrostatic supercharger compared to superchargers having only a constant section channel 3 at the output.

Claims (1)

An electrostatic supercharger comprising a housing with an inlet confuser, an output and a constant cross-section channel, a discharge electrode collecting an electrode connected to a high-voltage direct current source and installed in parallel planes perpendicular to the longitudinal axis of the constant cross-section channel, characterized in that the housing output is designed as an output diffuser.