JPH10160620A - Flow measurement device and flow distribution measurement device using the same - Google Patents

Abstract

(57) [Problem] To provide a flow measuring device and a flow distribution measuring device for measuring a flow distribution of a gas in a narrow space. SOLUTION: A plurality of round bar-shaped sensor heads 1 arranged at intervals and having an axial direction in a direction substantially orthogonal to the flow.
The current flowing through each sensor head 1 and the flow rate of the gas flowing around each sensor head 1 are calculated using the current value when the amount of heat generated and the amount of heat generated by the gas flowing around the sensor head 1 are balanced. A measurement calculation device 3 for calculating a flow angle, wherein the sensor head 1 includes an insulating round bar 4,
It consists of two metal films 5a and 5b attached to the surface of the round bar. The two metal films 5a and 5b have the same area and are spaced apart from each other in the circumferential direction with respect to the diameter of the round bar 4 in a predetermined direction. The predetermined direction is the same direction as each of the round bars, and the measurement and calculation device 3 causes a current to flow through each of the metal films 5a and 5b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device for measuring a flow behind a wing or the like and its distribution, and more particularly to a device for measuring a flow and a distribution in a narrow space.

[0002]

2. Description of the Related Art In order to grasp the performance of a fan compressor or the like, it is necessary to measure a wake distribution of a stationary blade, that is, a flow distribution behind a stationary blade. Conventionally, as shown in FIG.
The sensor head 1 is provided at the tip of the (rake) type support,
The sensor head 1 was provided with a pitot tube to measure the flow velocity distribution. However, the pitot tube cannot measure the flow angle. Therefore, as shown in FIG. 6, an X-type hot wire crossing a hot wire is used instead of the pitot tube to measure the flow angle. The hot wire is a platinum wire or a tungsten wire used for a hot wire anemometer. The current is applied to the wire and heated. . The flow angle can be calculated from experimental data representing the relationship between the ratio of the calorific value of the two hot wires and the flow angle of the fluid flowing into the two hot wires.

[0003]

When measuring the flow angle with such an X-type hot wire, the width of X needs to be about 5 mm, and when it is attached to the rake 2 shown in FIG.
Has a width of about 25 mm. On the other hand, in order to measure the wake distribution of the stator vanes of a small compressor, it is desirable to measure the distribution of the flow velocity and the flow angle at a pitch of at most 5 mm, that is, about 1 mm pitch, when the rake 2 is wide.

The present invention has been made in view of the above problems, and has as its object to provide a gas flow in a narrow space, a flow for measuring the distribution of the gas, and a distribution measuring device therefor.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, a round-bar-shaped sensor head, and an electric power supplied to the sensor head for heating, the amount of generated heat and a gas flowing around the sensor head. A measuring and calculating device for calculating the flow velocity and the flow angle of the gas flowing around the sensor head using the current value when the amount of heat deprived is equilibrated, wherein the sensor head has an insulating round bar, The two metal films have the same area and are arranged symmetrically at a circumferential distance with respect to the diameter of the round bar in a predetermined direction; The measurement operation device applies a current to each metal film.

[0006] Two metal films having the same area are insulated from each other by a gap and are attached line-symmetrically to one diameter on the round bar. Each metal film is energized. The relationship between the calorific value based on the current value and the gas flow rate based on the current value when the calorific value of the two metal films of the round bar and the calorie removed by the gas flowing around are equilibrium is obtained experimentally in advance. A flow rate can be obtained. In addition, the relationship between the calorific value of each metal film and the gas flow angle when equilibrated is experimentally obtained in advance, and the calorific value of each metal film can be obtained from the supplied current to obtain the gas flow angle. .

According to the second aspect of the present invention, a plurality of round bar-shaped sensor heads which are arranged at intervals and have an axial direction substantially perpendicular to the flow, and each of the sensor heads is energized and heated to generate heat. A measurement calculation device that calculates the flow velocity and flow angle of the gas flowing around each sensor head using the current value when the amount of heat taken by the gas flowing around the sensor head is balanced, and wherein the sensor head is insulated. Of a round bar and two metal films attached to the surface of the round bar. The two metal films have the same area and are spaced apart from each other in the circumferential direction with respect to the diameter of the round bar in a predetermined direction. And the predetermined direction is the same direction as each of the round bars, and the measurement and calculation device causes a current to flow through each metal film.

Each round bar is provided with two metal films having the same area, which are insulated from each other by having a gap and are attached in line symmetry with respect to one diameter, and the metal films are energized. The flow rate of the gas is obtained by experimentally obtaining in advance the relationship between the current value and the flow rate of the gas when the calorific value of the two metal films of each round bar and the heat quantity taken away by the gas flowing around are balanced. be able to. In addition, the relationship between the calorific value of both metal films and the gas flow angle when equilibrated is experimentally obtained in advance, and the calorific value of each metal film can be obtained from the supplied current to obtain the gas flow angle. By arranging such round bars with the metal film at a plurality of intervals, a distribution of flow velocity and flow angle can be obtained. In addition, even if the diameter of the round bar is considerably smaller than the X-type hot wire, the flow velocity and the flow angle can be measured, and the width of the rake can be reduced when it is attached to a rake having five hands.
The distribution of flow in a narrow space can be measured.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the present invention. The cylindrical sensor heads 1 are vertically arranged at predetermined intervals and supported by a rake 2 so as not to disturb the flow. The measurement calculation device 3 supplies a current to each sensor head 1 and calculates a flow velocity, a flow angle, and the like from the current value and the resistance value of the sensor head 1. The sensor head 1 is formed by depositing a metal film 5 on an insulating round bar 4, for example, ceramics, and uses nickel or the like as a metal. The metal film 5 is composed of two metal films 5a and 5b arranged so that one diameter is line-symmetric. This metal film 5
a and 5b have the same area, and the direction of one diameter is the same in all the sensor heads 1 and is the front-back direction of the rake 2. The rake 2 is set downstream of the stationary blade 6.

FIG. 2 is a sectional view of the sensor head 1 and the stationary blade 6. In each sensor head 1, metal films 5a and 5b are deposited symmetrically about the same diametric direction, and both metal films 5a and 5b are separated by a gap 7. A current is supplied to each of the metal films 5a and 5b by a conductor (not shown). As an example of the dimensions, the diameter of the round bar 4 is 0.2 mm, and the metal film 5 is 1-1.
The distance between the centers of the sensor heads 1 is about 0.4 to 0.6 mm, and the total width of the five rakes 2 is about 3 mm.

The flow velocity is calculated by a method similar to that of the hot wire anemometer. When the metal film 5 is heated by passing an electric current through the metal film 5 and placed in a gas, the following equation is established between the amount of heat H lost per unit length of the metal film 5 in the axial direction of the round bar 4 and the flow velocity v. H = B√v + C (1) where B and C are device constants. If the electric resistance of the metal film 5 is R and the current is I, the equation (1) is as follows. I ² R = B√v + C (2)

When the amount of heat to be supplied and the amount of heat lost by the gas are balanced, that is, the current value I _S at the time when the value of the supplied current has settled to a constant value is substituted into the equation (2) to obtain the flow velocity v. it can. The current I in this case may be a current when the metal films 5a and 5b are connected in series. Note that if the voltage is V, V = IR, so (2)
Can be represented by IV, so that the value of the resistor R (which varies with temperature) is not necessary.

FIG. 3 is a diagram showing an example of the measured flow velocity v. The horizontal axis represents time, and the vertical axis represents flow velocity v. The flow velocity v fluctuates in steps, the average value is vm, and the fluctuation width is Δv
Then, the ratio Δv / vm (fluctuation degree) between the fluctuation width and the average value
Can be obtained.

FIG. 4 is a diagram for explaining a method of calculating the flow angle θ. (A) shows the relationship between the metal films 5a and 5b and the flow angle θ. (B) is a diagram showing the relationship between the amount of heat Ea generated in the metal film 5a, the amount of heat Eb generated in the metal film 5b, and the flow angle θ. The amounts of heat Ea and Eb are the amounts of heat when the amount of heat supplied to the metal films 5a and 5b and the amount of heat taken by the gas flowing therearound are balanced. Whether or not equilibrium can be determined by whether or not the supplied current has settled to a constant value, and the heat amounts Ea and Eb can be calculated from the constant value current. When the flow angle θ calculated from Ea and Eb is different, it is preferable to take an average angle θm.

[0015]

As is apparent from the above description, according to the present invention, the current flow rate, the flow angle, and the turbulence are further measured by applying a current to a sensor head in which two metal films are attached to a round bar and measuring the amount of heat generated. The degree can be calculated. Also, by providing the sensor heads on the hands of a rake, a very compact flow distribution measuring device can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a sectional view of a stationary blade and a sensor head.

FIG. 3 is a diagram showing a flow velocity, an average flow velocity, and a turbulence degree.

FIG. 4 is a diagram illustrating a relationship between a flow angle and a heat generation amount of a sensor head.

FIG. 5 is a diagram showing a conventional flow distribution measuring device.

FIG. 6 is a view showing an X-type hot wire.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sensor head 2 Rake 3 Measurement arithmetic unit 4 Round bar 5, 5a, 5b Metal film 6 Stator blade 7 Gap

Claims (2)

[Claims] 1. A sensor head having a round bar shape and a current value obtained when the amount of heat generated by energizing and heating the sensor head and the amount of heat deprived by gas flowing around the sensor head are equilibrated. A measuring and calculating device for calculating the flow velocity and the flow angle of the flowing gas, wherein the sensor head comprises an insulating round bar and two metal films adhered to the surface of the round bar. The flow measurement is characterized in that the metal films have the same area and are arranged line-symmetrically at intervals in the circumferential direction with respect to the diameter of the round bar in a predetermined direction, and the measurement operation device supplies a current to each metal film. apparatus. 2. A plurality of sensor heads in the form of a round bar which are arranged at intervals and have an axial direction substantially perpendicular to the flow, and each of the sensor heads is energized and heated to generate heat and flow around the sensor heads. A measurement calculation device that calculates the flow velocity and flow angle of the gas flowing around each sensor head using the current value when the amount of heat deprived by the gas is equilibrated, and the sensor head has an insulating round bar and And two metal films attached to the surface of the round bar. The two metal films have the same area and are arranged symmetrically at a circumferential distance from a diameter of the round bar in a predetermined direction. The predetermined direction is the same direction for each of the round bars, and the measurement and calculation device applies a current to each metal film.