Star type three-phase alternating current arc heater electric heat conversion efficiency test system and method

Abstract

This invention provides a system and method for testing the electrothermal conversion efficiency of a star-shaped three-phase AC arc heater. A power output measurement unit measures the voltage and current at the output terminals of the three-phase AC power supply and calculates the power output power P1. A heater power measurement unit measures the voltage and current of each phase of the arc in the three-phase AC arc heater and calculates the heater power P2. A gas medium measurement unit and a heater body testing unit measure the energy P3 output by the working plasma gas in the heater. The thermal efficiency η1 and the electrothermal conversion system efficiency η2 of the star-shaped three-phase AC arc heater can be calculated. This invention enables online real-time monitoring of the entire system's electrical energy conversion efficiency and the heater's thermal efficiency during operation. It also allows analysis of energy losses in various parts of the arc heater and reactive power losses in the entire electrothermal system, providing guidance for heater operation optimization and performance improvement.

Description

Technical Field

[0001] This invention relates to the field of arc plasma heating technology, and in particular to a system and method for testing the electrothermal conversion efficiency of a star-shaped three-phase AC arc heater. Background Technology

[0002] An arc heater is a system that uses electric arc discharge to generate high-temperature plasma to heat gas. The gas is then accelerated through a nozzle to create a high-temperature, high-speed airflow environment. It is used for arc heating tests of aircraft thermal protection and is also an important heating device in various thermal applications in the industrial field. Arc heaters can heat almost any gaseous medium, have a wide operating range, and offer high reliability and stability. Three-phase AC arc heaters, as an important form of generating arc plasma, are increasingly widely used.

[0003] However, in the process of converting electrical energy into heat energy in a three-phase AC arc heater system, from the perspective of energy conversion, since the heating of gas in the arc chamber and mixing chamber of the arc heater is carried out through the interaction between the gas and the arc, various losses will inevitably occur due to the efficiency issues of water cooling and energy exchange in the system.

[0004] The existing technology lacks a systematic energy conversion testing device for three-phase AC arc heaters and a method for calculating and analyzing the energy conversion of heating systems. Summary of the Invention

[0005] The purpose of this invention is to provide a system and method for testing the electrothermal conversion efficiency of a star-type three-phase AC arc heater, which can accurately calculate the system efficiency, heater thermal efficiency, and energy loss of each part of the star-type three-phase AC arc heater. This invention provides a star-shaped three-phase AC arc heater electrothermal conversion efficiency testing system, comprising: a power output power measurement unit for measuring the voltage and current at the output terminal of the three-phase AC power supply and calculating the power output power P1; a heater power measurement unit for measuring the voltage and current of each phase arc of the three-phase AC arc heater and calculating the heater power P2; a gas medium measurement unit and a heater body testing unit for measuring the energy P3 output by the plasma working gas of the heater.

[0006] Furthermore, the power output measurement unit includes at least three sets of current sensors and voltage sensors for testing the current and voltage at the output terminals of the three-phase AC power supply.

[0007] Furthermore, the heater power measurement unit includes at least three sets of current sensors connected in series with each phase electrode cable in the AC arc heater, and at least three sets of voltage sensors connected to the connector end and ground end of each phase electrode cable in the AC arc heater.

[0008] Furthermore: the heater body testing unit includes a pressure sensor disposed in front of the nozzle throat of the heater; the gas medium measuring unit includes a sonic nozzle on the gas pipeline and a pipeline pressure measuring device in front of the sonic nozzle.

[0009] Furthermore, it also includes a cooling water parameter measurement unit for measuring the water cooling loss P4 of the heater.

[0010] Furthermore, the cooling water parameter measurement unit includes a mass flow measurement device for testing the cooling water inlet of each phase electrode and the heater mixing chamber, and a temperature measurement device for testing the cooling water inlet and outlet of each phase electrode, the heater mixing chamber, and the heater nozzle.

[0011] The present invention also provides a test method based on the aforementioned star-type three-phase AC arc heater electrothermal conversion efficiency test system, wherein the heater thermal efficiency η1 of the star-type three-phase AC arc heater is η1 = (P3 / P2) × 100%; and the electrothermal conversion system efficiency η2 of the star-type three-phase AC arc heater is η2 = (P3 / P1) × 100%.

[0012] Furthermore: P1 = Where U is the effective value of the AC voltage u(t) measured by the power output power measurement unit, and I is the effective value of the AC current i(t) measured by the power output power measurement unit. P2= Among them, the voltage and current of each phase collected by the heater power measurement unit are U i (t) and I i (t), i=A,B,C; for each phase current I i (t), select N current waveform peaks within a time span of at least one AC current variation cycle. n is 1, 2, 3..., N; the effective value of each phase current is I. i = For the voltage of each phase arc, its effective value is taken as U. i = ; P3= Where p0 is the total pressure in front of the heater nozzle throat as measured by the pressure sensor in the heater body parameter measurement unit; d0 is the diameter of the heater nozzle throat; p1 is the pipe pressure in front of the sonic nozzle as measured by the pressure measuring device in the gas medium measurement unit; d1 is the diameter of the sonic nozzle throat. For the selected heater working medium characteristic number, take the following for the working gas entering the heater at room temperature: γ and R are the adiabatic index and gas constant of the corresponding gas, respectively.

[0013] The present invention also provides a test method based on the aforementioned star-type three-phase AC arc heater electrothermal conversion efficiency test system, wherein the heater thermal efficiency η1 of the star-type three-phase AC arc heater is (1-P4 / P2)×100%.

[0014] Furthermore: ,in, G i The cooling water parameter measurement unit uses a mass flow measurement device to measure the mass flow rate, ΔT. i The cooling water parameter measurement unit uses a temperature measuring device to test the temperature increment of the cooling water inlet and outlet.

[0015] This invention can realize online real-time monitoring of the entire system's electrical energy conversion efficiency and the heater's thermal efficiency during the operation of a star-type three-phase AC arc heater. It can also analyze the energy loss of each part of the arc heater and the reactive power loss of the entire electrothermal system, which can be used to guide the optimization of heater operation and performance improvement. Attached Figure Description

[0016] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the electrothermal conversion efficiency testing system for the star-shaped three-phase AC arc heater of the present invention; Figure 2 This is a schematic diagram of the heater body testing unit and cooling water parameter measurement unit at the heater mixing chamber and nozzle positions of the present invention. Explanation of reference numerals in the attached figures: I - Current sensor; V - Voltage sensor; T1 - Cooling water inlet temperature measuring device; T2 - Cooling water outlet temperature measuring device; G1 - Mass flow rate measuring device for phase B electrode; G2 - Mass flow rate measuring device for phase A electrode; G3 - Mass flow rate measuring device for phase C electrode; G4 - Mass flow rate measuring device for heater mixing chamber and nozzle; P - Pressure sensor. Detailed Implementation

[0018] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection or an electrical connection; they may refer to a direct connection or an indirect connection through an intermediate medium; and they may refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0021] Example 1 like Figure 1 As shown, this invention provides a star-type three-phase AC arc heater electrothermal conversion efficiency testing system, comprising: a power output power measurement unit for measuring the voltage and current at the output terminal of a three-phase AC power supply (including a voltage regulator and a reactor) and calculating the power output power P1; a heater power measurement unit for measuring the voltage and current of each phase arc of a star-connected three-phase AC arc heater (including three electrodes, an arc chamber, a mixing chamber, and a nozzle) and calculating the heater power P2; a gas medium measurement unit and a heater body testing unit for measuring the energy P3 output by the plasma working gas of the heater.

[0022] Specifically, in this embodiment, the power output power measurement unit tests the relevant parameters of the power output terminal and calculates the power output power P1; the heater power measurement unit tests the relevant electrical parameters of the heater and calculates the heater power P2; the gas medium measurement unit and the heater body test unit test the relevant parameters and calculate the energy P3 output by the heater plasma working gas; the heater thermal efficiency η1 = (P3 / P2) × 100% of the star-shaped three-phase AC arc heater is obtained by direct calculation; and the electrothermal conversion system efficiency η2 = (P3 / P1) × 100% of the star-shaped three-phase AC arc heater is obtained by calculation.

[0023] Example 2 The power output measurement unit includes at least three sets of current sensors I and voltage sensors V for testing the current and voltage at the output of the three-phase AC power supply.

[0024] Specifically, in this embodiment, the power output measurement unit uses three sets of current sensors I and voltage sensors V to test the current and voltage at the output terminal of the three-phase AC power supply. The current sensor I is a Hall-effect closed-loop zero-flux current sensor I, and the cable at the output terminal of the reactor is passed through it and connected in series at a certain position. The voltage sensor V is a zero-flux high-voltage withstand voltage sensor V, and its two ends are connected to the power output terminal and the ground terminal, respectively.

[0025] Example 3 The heater power measurement unit includes at least three sets of current sensors I connected in series with each phase electrode cable in the AC arc heater, and at least three sets of voltage sensors V connected to the connector end and ground end of each phase electrode cable in the AC arc heater.

[0026] Specifically, in this embodiment, the heater power measurement unit uses three sets of current sensors I and voltage sensors V to test the current and voltage of each phase arc during the operation of the three-phase AC arc heater. The current sensor I is a Hall closed-loop zero-flux current sensor, which is connected in series to the cable of one phase electrode in the AC arc heater. The voltage sensor V is a zero-flux high-voltage withstand voltage sensor, and its two ends are respectively connected to the cable connector of one phase electrode in the AC arc heater and the ground terminal.

[0027] Example 4 like Figure 2 As shown, the heater body testing unit includes a pressure sensor located in front of the nozzle throat of the heater; the gas medium measurement unit includes a sonic nozzle on the gas pipeline and a pipeline pressure measuring device in front of the sonic nozzle.

[0028] Specifically, in this embodiment, the heater body parameter measurement unit uses a pressure sensor P to test the total pressure before the nozzle throat of the heater, denoted as p0. The designed nozzle throat diameter is denoted as d0. The gas medium measurement unit includes a sonic nozzle on the gas pipeline and a pipeline pressure measuring device (such as a pressure sensor P) before the sonic nozzle. The pipeline pressure before the sonic nozzle obtained by the test is denoted as p1, and the nozzle throat diameter is denoted as d1.

[0029] Example 5 like Figure 1 As shown, it also includes a cooling water parameter measurement unit for measuring the water cooling loss P4 of the heater.

[0030] Specifically, in this embodiment, the heater power measurement unit tests the relevant electrical parameters of the heater and calculates the heater power P2, and the cooling water parameter measurement unit tests the relevant parameters of the cooling water system and calculates the heater water cooling loss P4; the heater thermal efficiency η1 = (1-P4 / P2) × 100% is calculated by the indirect method.

[0031] Example 6 like Figure 1 and Figure 2 As shown, the cooling water parameter measurement unit includes a mass flow measurement device for testing the cooling water inlet of each phase electrode and the heater mixing chamber, and a temperature measurement device for testing the cooling water inlet and outlet of each phase electrode, the heater mixing chamber, and the heater nozzle.

[0032] Specifically, in this embodiment, the cooling water parameter measurement unit includes cooling water inlet mass flow measurement devices G1, G2, G3, and G4 (such as flow meters) for each phase electrode, heater mixing chamber, and nozzle, and cooling water inlet and outlet temperature measurement devices T1 and T2 (such as temperature sensors). The mass flow rate obtained on each cooling water pipeline is denoted as G. i The temperature increment of each portion of the cooling water inlet and outlet (T2-T1) is denoted as ΔT. i .

[0033] Example 7 The present invention also provides a direct testing method for the electrothermal conversion efficiency testing system of a star-type three-phase AC arc heater. For a power frequency three-phase AC power supply, the AC voltage u(t) and AC current i(t) measured by the power supply output power measurement unit are taken as effective values ​​U and I of voltage and current, and the power output power P1=3UI is calculated.

[0034] The voltage and current of each phase collected by the heater power measurement unit are U i (t) and I i (t), i=A,B,C, and the measured arc current I is... i(t) is approximately sinusoidal, for each phase current I i (t), select N current waveform peaks within a certain time span (at least greater than one AC current variation cycle). n is 1, 2, 3..., N, and the effective value of the current in each phase is I. i = For the voltage of each phase arc, its effective value is taken as U. i = The calculated power P2 of the star-type three-phase AC arc heater is... .

[0035] Based on the pipe pressure p1 obtained from the gas medium measurement unit test, the nozzle throat diameter d1 given in the design, and the total pressure p0 in front of the heater nozzle throat and the given heater nozzle throat diameter d0 obtained from the heater body parameter measurement unit test, the total energy of the working medium output by the heater is calculated as follows:

[0036] in For the selected heater working medium characteristic number, take the following for the working gas entering the heater at room temperature: γ and R are the adiabatic index and gas constant of the corresponding gas, respectively; The thermal efficiency of the star-type three-phase AC arc heater is calculated using the direct method as η1 = (P3 / P2) × 100%; the electrothermal conversion system efficiency of the star-type three-phase AC arc heater is calculated as η2 = (P3 / P1) × 100%. The reactive power loss of the three-phase AC arc heating system is calculated as P5 = P1 - P2.

[0037] Example 8 This invention also provides an indirect testing method based on a star-type three-phase AC arc heater electrothermal conversion efficiency testing system, wherein the voltage and current of each phase collected by the heater power measurement unit are U i (t) and I i (t), i=A,B,C, and the measured arc current I is... i (t) is approximately sinusoidal, for each phase current I i (t), select N current waveform peaks within a certain time span (at least greater than one AC current variation cycle). n is 1, 2, 3..., N, and the effective value of the current in each phase is I. i = For the voltage of each phase arc, its effective value is taken as U. i = The calculated power P2 of the star-type three-phase AC arc heater is... . Mass flow rate G obtained from the cooling water parameter measurement unit i The obtained temperature increment ΔT of each portion of cooling water inlet and outlet is... i The calculated heat loss of the heater is... .in, .

[0038] The thermal efficiency of the star-shaped three-phase AC arc heater is calculated by the indirect method as η1 = (1 - P4 / P2) × 100%.

[0039] The undisclosed technologies in this invention are common knowledge to those skilled in the art.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A system for testing the electrothermal conversion efficiency of a star-shaped three-phase AC arc heater, characterized in that, include: The power output measurement unit is used to measure the voltage and current at the output terminal of a three-phase AC power supply and to calculate the power output power P1. The heater power measurement unit is used to measure the voltage and current of each phase arc of the three-phase AC arc heater and calculate the heater power P2. The gas medium measurement unit and heater body test unit are used to measure the energy P3 output by the plasma working gas of the heater.

2. The electrothermal conversion efficiency testing system for a star-shaped three-phase AC arc heater according to claim 1, characterized in that, The power output measurement unit includes at least three sets of current sensors and voltage sensors for testing the current and voltage at the output of the three-phase AC power supply.

3. The electrothermal conversion efficiency testing system for a star-shaped three-phase AC arc heater according to claim 1, characterized in that, The heater power measurement unit includes at least three sets of current sensors connected in series with each phase electrode cable in the AC arc heater, and at least three sets of voltage sensors connected to the connector end and ground end of each phase electrode cable in the AC arc heater.

4. The electrothermal conversion efficiency testing system for a star-shaped three-phase AC arc heater according to claim 1, characterized in that: The heater body test unit includes a pressure sensor located in front of the nozzle throat of the heater. The gas medium measurement unit includes a sonic nozzle on the gas pipeline and a pipeline pressure measuring device in front of the sonic nozzle.

5. The electrothermal conversion efficiency testing system for a star-shaped three-phase AC arc heater according to claim 1, characterized in that, It also includes a cooling water parameter measurement unit for measuring the water cooling loss P4 of the heater.

6. The electrothermal conversion efficiency testing system for a star-shaped three-phase AC arc heater according to claim 5, characterized in that, The cooling water parameter measurement unit includes a mass flow measurement device for testing the cooling water inlet of each phase electrode and the heater mixing chamber, and a temperature measurement device for testing the cooling water inlet and outlet of each phase electrode, the heater mixing chamber, and the heater nozzle.

7. A test method for the electrothermal conversion efficiency test system of a star-shaped three-phase AC arc heater according to any one of claims 1-4, characterized in that: The heater thermal efficiency η1 of a star-type three-phase AC arc heater is calculated as (P3 / P2) × 100%. The efficiency of the electrothermal conversion system of the star-shaped three-phase AC arc heater is η2 = (P3 / P1) × 100%.

8. The electrothermal conversion efficiency testing system for a star-shaped three-phase AC arc heater according to claim 7, characterized in that: P1= Where U is the effective value of the AC voltage u(t) measured by the power output power measurement unit, and I is the effective value of the AC current i(t) measured by the power output power measurement unit. P2= Among them, the voltage and current of each phase collected by the heater power measurement unit are U i (t) and I i (t), i = A, B, C; for each phase current I i (t), select N current waveform peaks within a time span of at least one AC current variation cycle. n is 1, 2, 3..., N; the effective value of each phase current is I. i = For the voltage of each phase arc, its effective value is taken as U. i = ; P3= Where p0 is the total pressure in front of the heater nozzle throat as measured by the pressure sensor in the heater body parameter measurement unit; d0 is the diameter of the heater nozzle throat; p1 is the pipe pressure in front of the sonic nozzle as measured by the pressure measuring device in the gas medium measurement unit; d1 is the diameter of the sonic nozzle throat. For the selected heater working medium characteristic number, take the following for the working gas entering the heater at room temperature: γ and R are the adiabatic index and gas constant of the corresponding gas, respectively.

9. A test method for the electrothermal conversion efficiency test system of the star-shaped three-phase AC arc heater as described in claim 5 or 6, characterized in that: The thermal efficiency of a star-type three-phase AC arc heater is η1 = (1 - P4 / P2) × 100%.

10. The electrothermal conversion efficiency testing system for a star-shaped three-phase AC arc heater according to claim 9, characterized in that: ,in, G i The cooling water parameter measurement unit uses a mass flow measurement device to measure the mass flow rate, ΔT. i The cooling water parameter measurement unit uses a temperature measuring device to test the temperature increment of the cooling water inlet and outlet.

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