A performance testing method for a Stirling engine experimental apparatus

Abstract

This invention provides a performance testing method for a Stirling engine experimental apparatus, applied to a low-temperature Stirling engine demonstration experimental apparatus. The low-temperature Stirling engine demonstration experimental apparatus includes a Stirling engine and an insulated container, comprising the following steps: S1. Assembling a measuring sensor; S2. Injecting a predetermined amount of water at a predetermined temperature into the insulated container; S3. Opening the DAM3000M measurement and control system on a computer, the data acquisition card collects gas pressure, displacement, and water temperature data, and saves them in the computer as CSV files; S4. Plotting the change of pressure p with gas volume V and recording it as a p-V image; S5. Plotting the change of gas work W with time t and recording it as a W-t image, the change of output power P with time t and recording it as a P-t image, and the change of engine efficiency η with time t and recording it as an η-t image; S6. Combining the p-V image, W-t image, P-t image, and η-t image to perform performance analysis.

Description

Technical Field

[0001] This invention relates to the field of performance testing technology for physical experimental instruments, and in particular to a performance testing method for a Stirling engine thermal experiment apparatus. Background Technology

[0002] A Stirling engine is a reciprocating heat engine based on the Stirling cycle. An ideal Stirling cycle consists of four processes: isothermal expansion, isochoric cooling, isothermal compression, and isochoric heating. The Stirling engine operates based on this cycle of four processes.

[0003] Existing experimental instruments can measure and plot pV images of the Stirling engine's cycle process, but research on the power and efficiency of the Stirling engine remains theoretical. Furthermore, existing volume measurement methods use helical winding, which has low accuracy and introduces resistance to the Stirling engine's operation. There is a lack of a platform for measuring and demonstrating the power and efficiency of the Stirling engine, resulting in overly simplistic outcomes for teaching and research. Summary of the Invention

[0004] To address the above problems, this invention provides a performance testing method for a Stirling engine experimental apparatus, which is implemented as follows:

[0005] A performance testing method for a Stirling engine experimental apparatus, applied to a low-temperature Stirling engine demonstration experimental apparatus, the low-temperature Stirling engine demonstration experimental apparatus comprising a Stirling engine and an insulated container, comprising the following steps:

[0006] S1. Assemble the measuring sensors, which include a pressure sensor, a displacement sensor, and a temperature sensor;

[0007] S2. Pour a predetermined amount of water at a predetermined temperature into the insulated container;

[0008] S3. Open the DAM3000M measurement and control system on the computer. The gas pressure p and volume V, and the real-time water temperature T are measured by pressure sensor, displacement sensor and temperature sensor. During the process, the data acquisition card will automatically collect gas pressure, displacement and water temperature data and save them in the form of CSV file on the computer.

[0009] S4. Save the CSV file as an Excel file. Use Python to read the displacement and pressure data in the Excel file. The displacement sensor data can be converted into gas volume, and the graph of pressure p versus gas volume V can be plotted and recorded as a pV graph.

[0010] S5. Using theoretical formulas, calculate the work done by the gas W and the output power P, as well as the heat engine efficiency using Python. Plot the graph of the gas work W as a function of time t and record it as the Wt graph, the graph of the output power P as a function of time t and record it as the Pt graph, and the graph of the heat engine efficiency η as a function of time t and record it as the η-t graph.

[0011] S6. Perform performance analysis by combining the pV image, Wt image, Pt image, and η-t image.

[0012] As a further improvement, the pressure sensor is a BPR-10A resistance strain gauge pressure sensor with an output current signal of 4-20mA, a range of -10-10Kpa, and an accuracy of 0.03%FS.

[0013] The displacement sensor is a BGL high-precision background suppression laser sensor with an output current signal of 4-20mA, a range of 35-435mm, and an accuracy of 0.03%FS.

[0014] The temperature sensor is a CWDZ21 split-type temperature transmitter, which outputs a current signal (4-20mA), has a range of -50-100℃, and an accuracy of 0.03%FS.

[0015] As a further improvement, the pressure sensor is threadedly connected to the low-temperature Stirling machine demonstration experimental apparatus, and the gas pressure is measured by the pressure sensor.

[0016] The displacement sensor is positioned above the small cylinder inside the low-temperature Stirling machine demonstration experimental apparatus. The displacement sensor is used to measure the distance between itself and the upper surface of the small cylinder, and the measured distance is converted into gas volume.

[0017] The temperature sensor is used to measure the temperature of the water inside the insulated container.

[0018] As a further improvement, the data acquisition card is the Altair DAM3000M acquisition module, which is compatible with the DAM3000M measurement and control system.

[0019] As a further improvement, the sampling frequency is 125Hz, and the total sampling time t 总 Determined by the number of samples × 125Hz;

[0020] The displacement sensor measures a distance L between itself and the small cylinder, and the gas volume V is divided into a large cylinder volume V. L and small cylinder volume V l The volume of the large air cylinder is:

[0021] V L =64.1917cm 3

[0022] The volume of the small cylinder changes with the position of the piston, and the specific formula is as follows:

[0023] V l =πr 2 (l max -l)

[0024] Where r is the radius of the smaller cylinder.

[0025] r = 6.1 × 10 -2 cm

[0026] l max l and l are the maximum distance and real-time distance between the displacement sensor and the small cylinder, respectively. Therefore, the gas volume is:

[0027] V = V L +V l =64.1917cm 3 +πr 2 (l max -l)

[0028] This allows us to plot the pV graph, which represents the change in pressure p as a function of gas volume V. We then use Python to integrate the pV graph to calculate the area, using the following formula:

[0029]

[0030] V1 and V2 are the initial and final volumes of the experimental gas, respectively, thus obtaining the work done by the gas W. Dividing this work W by time t yields the power P. Plotting the Wt graph of the gas's work W versus time t, and outputting the Pt graph of the power P versus time t.

[0031] As a further improvement, the temperature sensor measures the real-time water temperature T and can also measure the total sampling time t. 总 The change in temperature of the internal water, and the amount of heat input to the heat engine, can be expressed as the change in the internal energy of the water, and is derived from the following formula:

[0032] Q = cmΔT

[0033] Where c is the specific heat capacity of water, which can be considered a constant when the temperature change is small, m is the mass of water, and ΔT is the temperature change of water during the experiment. The change in internal energy Q of water can then be calculated.

[0034] As a further improvement, the efficiency of the Stirling machine is calculated using the following formula:

[0035]

[0036] This allows us to plot the efficiency η of the Stirling machine as a function of the parameters.

[0037] The beneficial effects of this invention are as follows:

[0038] 1. By using a displacement sensor to measure the volume change of the cylinder and converting it into gas volume change data, the low precision problem caused by the traditional method of spiral winding is avoided, the measurement accuracy is improved, and the performance of the experimental instrument can be more accurately controlled.

[0039] 2. In addition to outputting pV images, it also outputs Wt, Pt, and η-t images, providing a more comprehensive detection dimension for the tested experimental instruments. This allows for more effective identification of problems with the tested instruments, enabling more timely feedback and corresponding optimization adjustments. Attached Figure Description

[0040] Figure 1 pV image drawn for an embodiment of the present invention;

[0041] Figure 2 The Wt image drawn for an embodiment of the present invention;

[0042] Figure 3 The Pt image drawn for an embodiment of the present invention;

[0043] Figure 4 An η-t image plotted for an embodiment of the present invention;

[0044] Figure 5 This is a schematic diagram of the operating system interface during the data acquisition process in an embodiment of the present invention. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of them. 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. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention.

[0046] In the description of this invention, 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 with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0047] A performance testing method for a Stirling engine experimental apparatus, applied to a low-temperature Stirling engine demonstration experimental apparatus, the low-temperature Stirling engine demonstration experimental apparatus comprising a Stirling engine and an insulated container, comprising the following steps:

[0048] S1. Assemble the measuring sensors, which include a pressure sensor, a displacement sensor, and a temperature sensor;

[0049] S2. Pour a predetermined amount of water at a predetermined temperature into the insulated container;

[0050] S3. Open the DAM3000M measurement and control system on the computer. The gas pressure p and volume V, and the real-time water temperature T are measured by pressure sensor, displacement sensor and temperature sensor. During the process, the data acquisition card will automatically collect gas pressure, displacement and water temperature data and save them in the form of CSV file on the computer.

[0051] S4. Save the CSV file as an Excel file. Use Python to read the displacement and pressure data in the Excel file. The displacement sensor data can be converted into gas volume, and the graph of pressure p versus gas volume V can be plotted and recorded as a pV graph.

[0052] S5. Using theoretical formulas, calculate the work done by the gas W and the output power P, as well as the heat engine efficiency using Python. Plot the graph of the gas work W as a function of time t and record it as the Wt graph, the graph of the output power P as a function of time t and record it as the Pt graph, and the graph of the heat engine efficiency η as a function of time t and record it as the η-t graph.

[0053] S6. Perform performance analysis by combining the pV image, Wt image, Pt image, and η-t image.

[0054] As a further improvement, the pressure sensor is a BPR-10A resistance strain gauge pressure sensor with an output current signal of 4-20mA, a range of -10-10Kpa, and an accuracy of 0.03%FS.

[0055] The displacement sensor is a BGL high-precision background suppression laser sensor with an output current signal of 4-20mA, a range of 35-435mm, and an accuracy of 0.03%FS.

[0056] The temperature sensor is a CWDZ21 split-type temperature transmitter, which outputs a current signal (4-20mA), has a range of -50-100℃, and an accuracy of 0.03%FS.

[0057] As a further improvement, the pressure sensor is threadedly connected to the low-temperature Stirling machine demonstration experimental apparatus, and the gas pressure is measured by the pressure sensor.

[0058] The displacement sensor is positioned above the small cylinder inside the low-temperature Stirling machine demonstration experimental apparatus. The displacement sensor is used to measure the distance between itself and the upper surface of the small cylinder, and the measured distance is converted into gas volume.

[0059] The temperature sensor is used to measure the temperature of the water inside the insulated container.

[0060] As a further improvement, the data acquisition card is the Altair DAM3000M acquisition module, which is compatible with the DAM3000M measurement and control system.

[0061] Specifically, LabVIEW can be used to connect to a data acquisition card to collect data, and software such as Matlab and Origin can be used to process the acquired current and voltage signals.

[0062] As a further improvement, the sampling frequency is 125Hz, and the total sampling time t 总 Determined by the number of samples × 125Hz;

[0063] The displacement sensor measures a distance L between itself and the small cylinder, and the gas volume V is divided into a large cylinder volume V. L and small cylinder volume V l The volume of the large air cylinder is:

[0064] V L =64.1917cm 3

[0065] The volume of the small cylinder changes with the position of the piston, and the specific formula is as follows:

[0066] V l =πr 2 (l max -l)

[0067] Where r is the radius of the smaller cylinder.

[0068] r = 6.1 × 10 -2 cm

[0069] l max l and l are the maximum distance and real-time distance between the displacement sensor and the small cylinder, respectively. Therefore, the gas volume is:

[0070] V = V L +V l =64.1917cm 3 +πr 2 (l max -l)

[0071] This allows us to plot the pV graph, which represents the change in pressure p as a function of gas volume V. We then use Python to integrate the pV graph to calculate the area, using the following formula:

[0072]

[0073] V1 and V2 are the initial and final volumes of the experimental gas, respectively, thus obtaining the work done by the gas W. Dividing this work W by time t yields the power P. Plotting the Wt graph of the gas's work W versus time t, and outputting the Pt graph of the power P versus time t.

[0074] As a further improvement, the temperature sensor measures the real-time water temperature T and can also measure the total sampling time t. 总 The change in temperature of the internal water, and the amount of heat input to the heat engine, can be expressed as the change in the internal energy of the water, and is derived from the following formula:

[0075] Q = cmΔT

[0076] Where c is the specific heat capacity of water, which can be considered a constant when the temperature change is small, m is the mass of water, and ΔT is the temperature change of water during the experiment. The change in internal energy Q of water can then be calculated.

[0077] As a further improvement, the efficiency of the Stirling machine is calculated using the following formula:

[0078]

[0079] This allows us to plot the efficiency η of the Stirling machine as a function of the parameters.

[0080] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A performance testing method for a Stirling engine experimental apparatus, applied to a low-temperature Stirling engine demonstration experimental apparatus, wherein the low-temperature Stirling engine demonstration experimental apparatus comprises a Stirling engine and an insulated container, characterized in that, Includes the following steps: S1. Assemble the measuring sensors, which include a pressure sensor, a displacement sensor, and a temperature sensor; S2. Pour a predetermined amount of water at a predetermined temperature into the insulated container; S3. Open the DAM3000M measurement and control system on the computer. The gas pressure p and volume V, and the real-time water temperature T are measured by pressure sensor, displacement sensor and temperature sensor. During the process, the data acquisition card will automatically collect gas pressure, displacement and water temperature data and save them in the form of CSV file on the computer. S4. Save the CSV file as an Excel file. Use Python to read the displacement and pressure data in the Excel file. The displacement sensor data can be converted into gas volume, and the graph of pressure p versus gas volume V can be plotted and recorded as a pV graph. S5. Using theoretical formulas, calculate the work done by the gas W and the output power P, as well as the heat engine efficiency using Python. Plot the graph of the gas work W as a function of time t and record it as the Wt graph, the graph of the output power P as a function of time t and record it as the Pt graph, and the graph of the heat engine efficiency η as a function of time t and record it as the η-t graph. S6. Perform performance analysis by combining the pV image, Wt image, Pt image, and η-t image.

2. The performance testing method of the Stirling engine experimental apparatus as described in claim 1, characterized in that, The pressure sensor is a BPR-10A resistance strain gauge pressure sensor, with an output current signal of 4-20mA, a range of -10-10Kpa, and an accuracy of 0.03%FS. The displacement sensor is a BGL high-precision background suppression laser sensor with an output current signal of 4-20mA, a range of 35-435mm, and an accuracy of 0.03%FS. The temperature sensor is a CWDZ21 split-type temperature transmitter, which outputs a current signal (4-20mA), has a range of -50-100℃, and an accuracy of 0.03%FS.

3. The performance testing method of the Stirling engine experimental apparatus as described in claim 2, characterized in that, The pressure sensor is threadedly connected to the low-temperature Stirling machine demonstration experimental apparatus, and the gas pressure is measured by the pressure sensor. The displacement sensor is positioned above the small cylinder inside the low-temperature Stirling machine demonstration experimental apparatus. The displacement sensor is used to measure the distance between itself and the upper surface of the small cylinder, and the measured distance is converted into gas volume. The temperature sensor is used to measure the temperature of the water inside the insulated container.

4. The performance testing method of the Stirling engine experimental apparatus as described in claim 3, characterized in that, The data acquisition card is the Altair DAM3000M acquisition module that is compatible with the DAM3000M measurement and control system.

5. The performance testing method of the Stirling engine experimental apparatus as described in claim 1, characterized in that, The sampling frequency is 125Hz, and the total sampling time is t. 总 Determined by the number of samples × 125Hz; The displacement sensor measures a distance L between itself and the small cylinder, and the gas volume V is divided into a large cylinder volume V. L and small cylinder volume V l The volume of the large air cylinder is: In L =64.1917cm 3 The volume of the small cylinder changes with the position of the piston, and the specific formula is as follows: V l ＝πr 2 (l max -l) Where r is the radius of the smaller cylinder. r=6.1×10 -2 cm l max l and l are the maximum distance and real-time distance between the displacement sensor and the small cylinder, respectively. Therefore, the gas volume is: V=V L +V l =64.1917cm 3 +πr 2 (l max -l) This allows us to plot the pV graph, which represents the change in pressure p as a function of gas volume V. We then use Python to integrate the pV graph to calculate the area, using the following formula: V1 and V2 are the initial and final volumes of the experimental gas, respectively, thus obtaining the work done by the gas W. Dividing this work W by time t yields the power P. Plotting the Wt graph of the gas's work W versus time t, and outputting the Pt graph of the power P versus time t.

6. The performance testing method for a Stirling engine experimental apparatus as described in claim 5, characterized in that, The temperature sensor measures the real-time water temperature T, and the total sampling time t can be measured. 总 The change in temperature of the internal water, and the amount of heat input to the heat engine, can be expressed as the change in the internal energy of the water, and is derived from the following formula: Q = cmΔT Where c is the specific heat capacity of water, which can be considered a constant when the temperature change is small, m is the mass of water, and ΔT is the temperature change of water during the experiment.

7. The performance testing method for a Stirling engine experimental apparatus as described in claim 6, characterized in that, The efficiency of a Stirling machine is calculated using the following formula: This allows us to plot the efficiency η of the Stirling machine as a function of the parameters.

Images