Method and device for testing specific heat capacity of oil

Abstract

The invention discloses an oil specific heat capacity testing method and device, and the method comprises the steps: carrying out the heat exchange of one kind of oil with known specific heat capacity and another kind of oil with unknown specific heat capacity in a heat exchanger according to the principle that the heat absorption power, heat release power and heat dissipation power are equal in a heat exchange process; after inlet and outlet temperatures and outlet flows of a heat path and a cold path of the heat exchanger are measured during heat exchange, the heat dissipation power is calculated through the known oil specific heat capacity, and then the specific heat capacity of the oil to be measured is calculated according to the heat dissipation power. The testing device comprises a testing oil tank, an oil tank and a heat exchanger, inlets and outlets of a hot path and a cold path of the heat exchanger are respectively provided with a temperature sensor, and outlets of the hot path and the cold path are respectively provided with a flowmeter. According to the invention, the specific heat capacity of the oil can be rapidly and accurately tested, and the test cost is low.

Description

Technical Field

[0001] The present invention belongs to the technical field of simulation testing, relates to the testing of physical properties parameters of oil, and specifically is a method and device for testing the specific heat capacity of oil. Background Art

[0002] The fuel and lubricating oil radiator is one of the radiators produced most by the applicant at present. Before each radiator leaves the factory, performance testing is required. As the medium for performance testing of the fuel and lubricating oil radiator, the specific heat of the oil is an important physical property parameter, which directly affects the accuracy of the performance test results.

[0003] During the storage and use of the oil, the specific heat will gradually change. When the specific heat of the oil deviates greatly from the standard value, it brings great errors to the test. Therefore, during the use of the oil, it is necessary to regularly measure and calibrate its specific heat to ensure the accuracy of the performance test of the fuel and lubricating oil radiator.

[0004] Therefore, it is necessary to design a set of scientific, effective and practical testing devices according to the existing conditions, so as to accurately, conveniently, safely and quickly test the specific heat capacity of the oil. Summary of the Invention

[0005] The present invention aims to provide a method and device for testing the specific heat capacity of oil, which can accurately, conveniently, safely and quickly test the specific heat capacity of the oil. Further, the specific heat capacity testing method of the present invention can complete the testing of the specific heat capacity of unknown oil by using a conventional and typical radiator performance testing platform, reducing the testing cost.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for testing the specific heat capacity of oil, comprising:

[0008] Select an oil with a known specific heat capacity as a reference oil, conduct heat exchange between the reference oil and the oil to be tested with an unknown specific heat capacity in a heat exchanger. During the heat exchange, measure the inlet temperature of the reference oil, the outlet temperature of the reference oil, the inlet temperature of the oil to be tested, the outlet temperature of the oil to be tested, the outlet flow rate of the reference oil and the outlet flow rate of the oil to be tested in the heat exchanger respectively. Based on the fact that the heat dissipation power of the hot path in the heat exchanger is equal to the heat dissipation power of the cold path, obtain the specific heat capacity of the oil to be tested according to the following formula:

[0009] C2 = (C1 × G1 × △T1) / (G2 × △T2);

[0010] In the formula:

[0011] C1 is the specific heat capacity of the reference oil;

[0012] C2 is the specific heat capacity of the oil to be tested;

[0013] G1 is the reference oil outlet flow rate;

[0014] G2 is the oil to be measured outlet flow rate;

[0015] △T1 is the difference between the reference oil inlet temperature and the outlet temperature;

[0016] △T2 is the difference between the oil to be measured inlet temperature and the outlet temperature.

[0017] As an option, the reference oil serves as the hot path in the heat exchanger, and the oil to be measured serves as the cold path in the heat exchanger.

[0018] As a solution:

[0019] Take the reference oil as the hot path in the heat exchanger and the oil to be measured as the cold path in the heat exchanger. Obtain the first calculation result C of the specific heat capacity of the oil to be measured according to the formula C2 = (C1×G1×△T1) / (G2×△T2); 21 ;

[0020] Then take the reference oil as the cold path in the heat exchanger and the oil to be measured as the hot path in the heat exchanger. Obtain the second calculation result C of the specific heat capacity of the oil to be measured according to the formula C2 = (C1×G1×△T1) / (G2×△T2); 22 ;

[0021] Take the first calculation result C of the specific heat capacity of the oil to be measured 21 and the second calculation result C of the specific heat capacity of the oil to be measured 22 and take the average value as the final calculated value C of the specific heat capacity of the oil to be measured. 2终 .

[0022] The above solution can eliminate the error of the heat exchanger in calculating the specific heat capacity.

[0023] As another solution, the oil to be measured can always be used as the cold path in the heat exchanger, but the hot path in the heat exchanger is replaced with reference oils of different specifications. For each replacement of a specification of the reference oil, a calculated value of the specific heat capacity of the oil to be measured is obtained, and then the final calculated value of the specific heat capacity of the oil to be measured is obtained by calculating the average value of multiple calculated values of the specific heat capacity.

[0024] Furthermore, the method for testing the specific heat capacity of the oil includes the following steps:

[0025] Step 1: Pass the oil to be measured into the cold path of the heat exchanger and pass the reference oil into the hot path of the heat exchanger. When the outlet flow rate of the oil to be measured in the heat exchanger is stable at a preset value, adjust the inlet temperature of the reference oil in the heat exchanger to make it stable at the preset value;

[0026] Step 2: When the reference oil outlet flow rate in the heat exchanger stabilizes at a preset value, adjust the inlet temperature of the oil to be measured in the heat exchanger to make it stable at the preset value;

[0027] Step 3: Observe the outlet temperature of the oil to be measured and the outlet temperature of the reference oil in the heat exchanger. When both temperature values are stable, record the outlet temperature of the oil to be measured and the outlet temperature of the reference oil at this time;

[0028] Step 4: Take the outlet flow rate of the oil to be measured in Step 1 as G2, take the outlet flow rate of the reference oil in Step 2 as G1, take the absolute value of the difference between the inlet temperature of the oil to be measured in Step 2 and the outlet temperature of the oil to be measured in Step 3 as △T2, and take the absolute value of the difference between the inlet temperature of the reference oil in Step 1 and the outlet temperature of the reference oil in Step 3 as △T1.

[0029] As an option, the reference oil is a high-temperature resistant aviation lubricating oil.

[0030] An oil specific heat capacity testing device, comprising:

[0031] A heat exchanger;

[0032] A test fuel tank and a fuel tank. The test fuel tank is used for storing the oil to be measured and includes an oil inlet and an oil outlet. The fuel tank is used for storing the reference oil and includes an oil inlet and an oil outlet. The oil outlet of the test fuel tank is connected to the hot path inlet of the heat exchanger through a first pipeline. The oil outlet of the fuel tank is connected to the cold path inlet of the heat exchanger through a third pipeline. The hot path outlet of the heat exchanger is connected to the oil inlet of the test fuel tank through a second pipeline. The cold path outlet of the heat exchanger is connected to the oil inlet of the fuel tank through a fourth pipeline; or, the oil outlet of the test fuel tank is connected to the cold path inlet of the heat exchanger through a first pipeline. The oil outlet of the fuel tank is connected to the hot path inlet of the heat exchanger through a third pipeline. The cold path outlet of the heat exchanger is connected to the oil inlet of the test fuel tank through a second pipeline. The hot path outlet of the heat exchanger is connected to the oil inlet of the fuel tank through a fourth pipeline;

[0033] A first temperature sensor, which is arranged on the first pipeline;

[0034] A second temperature sensor, which is arranged on the third pipeline;

[0035] A third temperature sensor, which is arranged on the fourth pipeline;

[0036] A fourth temperature sensor, which is arranged on the second pipeline;

[0037] A first flowmeter, which is arranged on the fourth pipeline;

[0038] A second flowmeter, which is arranged on the second pipeline.

[0039] As a solution, the heat exchanger is a plate-fin heat exchanger or a shell-and-tube heat exchanger.

[0040] As a solution, the heat exchanger is wrapped with heat insulation cotton.

[0041] As a solution:

[0042] The oil outlet of the test fuel tank is connected to the cold inlet of the heat exchanger through the first pipeline, and the cold outlet of the heat exchanger is connected to the oil inlet of the test fuel tank through the second pipeline;

[0043] The oil outlet of the fuel tank is connected to the hot inlet of the heat exchanger through the third pipeline, and the hot outlet of the heat exchanger is connected to the oil inlet of the fuel tank through the fourth pipeline.

[0044] As a solution:

[0045] A second heater and a second pump are further provided on the first pipeline;

[0046] A first cooler is further provided on the second pipeline;

[0047] A first heater and a first pump are further provided on the third pipeline;

[0048] A second cooler is further provided on the fourth pipeline.

[0049] Compared with the prior art, the method and device for testing the specific heat capacity of oil have the following characteristics:

[0050] 1. The device for testing the specific heat capacity of oil of the present invention is a set of scientific, effective and practical testing device, which is accurate, convenient, safe and fast in testing.

[0051] 2. The test can be completed by using the existing performance test platform for fuel and lubricating oil radiators. As long as the radiator performance test platform can stably provide two paths of oil with certain temperature and flow for circulation, the test method of the present invention can be used. The application range of the radiator performance test platform, which is currently only used to test whether the heat transfer performance of the radiator meets the specified requirements, is expanded, and the test cost is reduced.

[0052] 3. The specific heat capacity of the oil to be tested can be calculated by exchanging the cold path and the hot path on the same set of device, or changing different media in the hot path while fixing the cold path, so as to eliminate the test error and obtain the specific heat capacity of the oil to be tested closer to the true value. Description of the Drawings

[0053] Figure 1 It is a schematic diagram of the principle of the device for testing the specific heat capacity of oil;

[0054] In the figure: 1 - test equipment, 2 - test oil tank, 3 - first temperature sensor, 4 - second temperature sensor, 5 - third temperature sensor, 6 - fourth temperature sensor, 7 - first flowmeter, 8 - second flowmeter, 9 - heat exchanger, 10 - first heater, 11 - first cooler, 12 - second heater, 13 - first pump, 14 - second pump, 15 - second cooler, 16 - oil tank. Detailed implementation mode

[0055] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. However, it should not be understood that the scope of the subject matter of the present invention is limited to the following embodiments. Without departing from the above technical idea of the present invention, all modifications, substitutions, and changes made according to ordinary technical knowledge and conventional means in the art are included in the scope of the present invention.

[0056] In order to test the specific heat capacity of the oil, the present invention utilizes the principle that the heat dissipation power of the hot path in the heat exchanger is equal to the heat dissipation power of the cold path (it should be noted that here the hot path and the cold path are respectively the heat exchange medium pipelines on the side with higher temperature and the side with lower temperature in the heat exchanger). Since the calculation formula for the heat dissipation power W of the heat exchanger is W = C×G×ΔT, where W is the heat dissipation power, C is the specific heat capacity, G is the flow rate, and ΔT is the temperature difference between the inlet and outlet. Denote the heat dissipation power of the hot path as W 1， Then W1 = C1×G1×ΔT1. Similarly, denote the heat dissipation power of the cold path as W2, then W2 = C2×G2×ΔT2.

[0057] Since W1 = W2, that is, C1×G1×ΔT1 = C2×G2×ΔT2. After arrangement, C2 = (C1×G1×ΔT1) / (G2×ΔT2). Thus, an oil with a known specific heat capacity can be selected as a reference to measure the specific heat capacity of another oil with an unknown specific heat capacity. Usually, the oil with a known specific heat capacity is a high-temperature resistant aviation lubricating oil because the high-temperature resistant aviation lubricating oil is relatively safer than fuel when heated. For example, 4106 aviation lubricating oil or 4050 aviation lubricating oil.

[0058] As a principle, selecting the oil to be tested as the cold path to enter the heat exchanger can avoid the oil to be tested from deteriorating (carbonizing) due to excessive heating. This is also the reason why the oil with a known specific heat capacity needs to be a high-temperature resistant aviation lubricating oil because the high-temperature resistant aviation lubricating oil as the hot path will not pose a safety hazard when heated.

[0059] Refer to Figure 1, which is the oil specific heat capacity testing device adopted by the present invention, includes a testing device 1, a testing fuel tank 2, a fuel tank 16, and a heat exchanger 9. The outside of the heat exchanger 9 is wrapped with heat insulation cotton. The testing device 1 includes a circulation loop A and a circulation loop B. Among them, the circulation loop A serves as the cold path of the heat exchanger 9 for the oil to be tested. After the oil to be tested is injected into the testing fuel tank 2, it flows into the heat exchanger 9 through the circulation loop A and then flows back into the testing fuel tank 2 through the circulation loop A. Similarly, the circulation loop B serves as the hot path of the heat exchanger 9 for the reference oil with a known specific heat capacity. The reference oil is stored in the fuel tank 16. The reference oil flows into the heat exchanger 9 through the circulation loop B and then flows out through the circulation loop B and returns to the fuel tank 16.

[0060] The heat exchanger 9 is connected to the circulation loop A and the circulation loop B of the testing device 1 through pipelines. At the inlet of the cold path (corresponding to the circulation loop A) of the heat exchanger 9, a first temperature sensor 3 is provided. Between the first temperature sensor 3 and the outlet of the testing fuel tank 2, a second pump 14 and a second heater 12 (for heating the oil) are also provided. At the outlet of the cold path of the heat exchanger 9, a fourth temperature sensor 6 is provided. Between the fourth temperature sensor 6 and the inlet of the testing fuel tank 2, a second flowmeter 8 and a first cooler 11 (for cooling the oil) are also provided; at the inlet of the hot path (corresponding to the circulation loop B) of the heat exchanger 9, a second temperature sensor 4 is provided. Between the second temperature sensor 4 and the outlet of the fuel tank 16, a first pump 13 and a first heater 10 (for heating the oil) are also provided. At the outlet of the hot path of the heat exchanger 9, a third temperature sensor 5 is provided. Between the third temperature sensor 5 and the inlet of the fuel tank 16, a first flowmeter 7 and a second cooler 15 (for cooling the oil) are also provided.

[0061] When testing the specific heat capacity of the oil, the two oil circulation loops of the testing device 1 need to be used, that is, the circulation loop A and the circulation loop B. The testing process is as follows:

[0062] Step 1, sampling and filling of the oil to be tested: Take 60 L of the oil to be tested and fill it into the testing fuel tank 2, and inject sufficient aviation lubricating oil into the fuel tank 16.

[0063] Step 2, setting of test parameters:

[0064] Parameters of the circulation loop A: flow rate is 1200 kg / h ± 50 kg / h; inlet temperature is 120 °C ± 2 °C;

[0065] Parameters of the circulation loop B: flow rate is 1200 kg / h ± 50 kg / h; inlet temperature is 70 °C ± 2 °C;

[0066] Step 3, start of testing:

[0067] After starting the test device 1, first adjust the second pump 14 to regulate the outlet flow rate of the circulation loop A (i.e., observe the cold-side outlet of the heat exchanger 9 through the second flowmeter 8) to be stable within the range of 1200 kg / h ± 50 kg / h. Then start the first heater 10 or the second cooler 15 in the test device 1 and regulate the inlet temperature of the hot side of the heat exchanger 9 to be stable at 120°C ± 2°C (through the third temperature sensor 4). At the same time, adjust the first pump 13 to enable the test device 1 to regulate the flow rate of the circulation loop B (by observing the first flowmeter 7) to be stable within the range of 1200 kg / h ± 50 kg / h. Then start the second heater 12 or the first cooler 11 and regulate the inlet temperature of the cold side of the heat exchanger 9 to be stable at 70°C ± 2°C (observed through the first temperature sensor 3).

[0068] Step 4, data recording:

[0069] After the cold-side outlet flow rate and outlet temperature of the circulation loop A, and the hot-side outlet flow rate and outlet temperature of the circulation loop B are stable, record the corresponding data as follows:

[0070] For example, the data of the circulation loop A are: the cold-side outlet flow rate is 1199 kg / h, the cold-side inlet temperature is 70°C, and the cold-side outlet temperature is 83°C;

[0071] For example, the data of the circulation loop B are: the hot-side outlet flow rate is 1211 kg / h, the hot-side inlet temperature is 120°C, and the hot-side outlet temperature is 105°C;

[0072] Step 5, calculation of the specific heat capacity of the oil to be tested:

[0073] According to the heat dissipation power W = W1 = C1×G1 / 3600×△T1 = W2 = C2×G2 / 3600×△T2;

[0074] By transposing and adjusting, we get C2 = (C1×G1×△T1) / (G2×△T2);

[0075] It is known that the specific heat capacity C1 of the reference oil is 2.476 kJ / kg / °C;

[0076] Then the specific heat capacity C2 of the oil to be tested = (C1×G1×△T1) / (G2×△T2) = 2.476 (kJ / kg / °C)×1199 (kg / h)×13 (°C) / (1211) kg / h / 15 (°C) = 2.1246 kJ / kg / °C.

[0077] It should be noted that dividing by 3600 in the above calculation process is for converting the flow rate G1. Here, the unit of the heat dissipation power W is kilowatt = kW = kJ / s = C1×G1×△T1 = kJ / kg / ℃×kg / s×℃. The unit of the flow rate measured by the flowmeter is kg / h. To convert it to kg / s, it needs to be divided by 3600, that is, the flow rate

[0078] 1200 kg / h = 1200 kg / h÷3600 s / h = 0.333 kg / s.

[0079] Those skilled in the art can make various adjustments to this application according to the actual situation. The general principles defined in this application can be implemented in other implementations without departing from the content. Therefore, this application will not be limited to the structure shown in the specific implementation manner, but should conform to the broadest scope consistent with the principles and characteristics described in the claims of this application.

Claims

1. A method for testing the specific heat capacity of oil, characterized in that: include: Select an oil with known specific heat capacity as the reference oil, and perform heat exchange between the reference oil and the test oil with unknown specific heat capacity in a heat exchanger. During the heat exchange, measure the reference oil inlet temperature, reference oil outlet temperature, test oil inlet temperature, test oil outlet temperature, reference oil outlet flow rate, and test oil outlet flow rate in the heat exchanger. Based on the fact that the heat dissipation power of the hot circuit in the heat exchanger is equal to the heat dissipation power of the cold circuit, the specific heat capacity of the test oil is obtained according to the following formula: C2=(C1×G1×△T1) / (G2×△T2); Where: C1 is the specific heat capacity of the reference oil; C2 is the specific heat capacity of the oil to be tested; G1 is the reference oil outlet flow rate; G2 is the outlet flow rate of the oil to be tested; △T1 is the difference between the inlet temperature and the outlet temperature of the reference oil; △T2 is the difference between the inlet temperature and the outlet temperature of the oil to be tested.

2. The method for testing the specific heat capacity of oil according to claim 1, characterized in that: The reference oil serves as a hot path in the heat exchanger, and the oil to be tested serves as a cold path in the heat exchanger.

3. The method for testing the specific heat capacity of oil according to claim 1, characterized in that: The reference oil is used as the hot path in the heat exchanger, and the oil to be tested is used as the cold path in the heat exchanger. According to the formula C2=(C1×G1×△T1) / (G2×△T2), the first calculation result C of the specific heat capacity of the oil to be tested is obtained. 21 ; Then, the reference oil is used as the cold path in the heat exchanger, and the oil to be tested is used as the hot path in the heat exchanger. According to the formula C2=(C1×G1×△T1) / (G2×△T2), the second calculation result C of the specific heat capacity of the oil to be tested is obtained. 22 ; Take the first calculation result C of the specific heat capacity of the oil to be tested 21 and the second calculation result of the specific heat capacity of the oil to be tested C 22 The average value of the specific heat capacity of the oil to be tested is taken as the final calculated value C 2终 .

4. The method for testing the specific heat capacity of oil according to claim 1, characterized in that: The following steps are involved: Step 1: introducing the oil to be tested into the cold circuit of the heat exchanger and introducing the reference oil into the hot circuit of the heat exchanger. When the outlet flow rate of the oil to be tested in the heat exchanger is stabilized at a preset value, adjusting the inlet temperature of the reference oil in the heat exchanger to stabilize it at a preset value. Step 2: When the reference oil outlet flow rate in the heat exchanger is stabilized at a preset value, the inlet temperature of the oil to be measured in the heat exchanger is adjusted to stabilize it at a preset value; Step 3, observe the outlet temperature of the oil to be tested and the outlet temperature of the reference oil in the heat exchanger, and when both temperature values ​​are stable, record the outlet temperature of the oil to be tested and the outlet temperature of the reference oil at this time; Step 4: Take the outlet flow rate of the oil to be measured in step 1 as G2, take the outlet flow rate of the reference oil in step 2 as G1, take the absolute value of the difference between the inlet temperature of the oil to be measured in step 2 and the outlet temperature of the oil to be measured in step 3 as △T2, take the absolute value of the difference between the inlet temperature of the reference oil in step 1 and the outlet temperature of the reference oil in step 3 as △T1.

5. The method for testing the specific heat capacity of oil according to claim 1, characterized in that: The reference oil is high temperature resistant aviation lubricating oil.

6. An oil specific heat capacity testing device, characterized in that: include: Heat exchanger (9); A test oil tank (2) and an oil tank (16), wherein the test oil tank (2) is used to store oil to be tested and comprises an oil inlet and an oil outlet, and the oil tank (16) is used to store reference oil and comprises an oil inlet and an oil outlet, the oil outlet of the test oil tank (2) is connected to the hot path inlet of the heat exchanger (9) via a first pipeline, the oil outlet of the oil tank (16) is connected to the cold path inlet of the heat exchanger (9) via a third pipeline, and the hot path outlet of the heat exchanger (9) is connected to the test oil tank (2) via a second pipeline. The oil inlet of the test oil tank (2) is connected to the cold circuit inlet of the heat exchanger (9), and the cold circuit outlet of the heat exchanger (9) is connected to the oil inlet of the oil tank (16) via a fourth pipeline; or, the oil outlet of the test oil tank (2) is connected to the cold circuit inlet of the heat exchanger (9) via a first pipeline, and the oil outlet of the oil tank (16) is connected to the hot circuit inlet of the heat exchanger (9) via a third pipeline, the cold circuit outlet of the heat exchanger (9) is connected to the oil inlet of the test oil tank (2) via a second pipeline, and the hot circuit outlet of the heat exchanger (9) is connected to the oil inlet of the oil tank (16) via a fourth pipeline; A first temperature sensor (3), the first temperature sensor (3) being arranged on a first pipeline; A second temperature sensor (4), the second temperature sensor (4) being arranged on the third pipeline; a third temperature sensor (5), the third temperature sensor (5) being arranged on the fourth pipeline; a fourth temperature sensor (6), the fourth temperature sensor (6) being arranged on the second pipeline; A first flow meter (7), wherein the first flow meter (7) is arranged on a fourth pipeline; A second flow meter (8), wherein the second flow meter (8) is arranged on the second pipeline.

7. The oil specific heat capacity testing device according to claim 6, characterized in that: The heat exchanger (9) is a plate-fin heat exchanger or a shell-and-tube heat exchanger.

8. The oil specific heat capacity testing device according to claim 6, characterized in that: The heat exchanger (9) is wrapped with heat insulation cotton.

9. The oil specific heat capacity testing device according to claim 6, characterized in that: The oil outlet of the test oil tank (2) is connected to the cold circuit inlet of the heat exchanger (9) via a first pipeline, and the cold circuit outlet of the heat exchanger (9) is connected to the oil inlet of the test oil tank (2) via a second pipeline; The oil outlet of the oil tank (16) is connected to the heat path inlet of the heat exchanger (9) via a third pipeline, and the heat path outlet of the heat exchanger (9) is connected to the oil inlet of the oil tank (16) via a fourth pipeline.

10. The oil specific heat capacity testing device according to claim 6, characterized in that: The first pipeline is also provided with a second heater (12) and a second pump (14); The second pipeline is also provided with a first cooler (11); The third pipeline is also provided with a first heater (10) and a first pump (13); The fourth pipeline is also provided with a second cooler (15).

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