CN112630118A - Gas permeability measuring device and measuring method for compact material - Google Patents
Gas permeability measuring device and measuring method for compact material Download PDFInfo
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Abstract
The invention discloses a gas permeability measuring device and a measuring method of a compact material, which comprise the following steps: the air inlet pipeline is communicated with the air source device; the upstream cavity is communicated with the air source device through an air inlet pipeline; the downstream cavity is communicated with the air source device through an air inlet pipeline; an upstream pressure sensor is connected with the upstream cavity to measure the pressure in the upstream cavity; the downstream pressure sensor is connected with the downstream cavity to measure the pressure in the downstream cavity; the holder is used for placing the test sample assembly and providing radial sealing for the test sample assembly, and is positioned between the upstream cavity and the downstream cavity and respectively communicated with the upstream cavity and the downstream cavity; the piston swing mechanism comprises a first piston and a second piston, the first piston is connected with the upstream cavity, the second piston is connected with the downstream cavity, the first piston and the second piston move synchronously to change the volume in the corresponding cavity, and the total volume of the upstream cavity, the gripper and the downstream cavity is kept unchanged.
Description
Technical Field
The invention relates to the technical field of material gas permeability measurement, in particular to a gas permeability measurement device and a gas permeability measurement method for a compact material.
Background
Unconventional natural gas resources represented by dense gas, coal bed gas and shale gas are key exploration and development objects of natural gas industries of countries in the world at present. Gas permeability (or diffusion coefficient) is a key parameter that determines the technical exploitation difficulty of reservoir gases and the yield of natural gas. The measurement of permeability (or diffusion coefficient) based on actual rock samples obtained by drilling and coring is an essential link in exploration procedures. Because shale or coal beds are compact rock reservoirs, the gas permeability value of the shale or coal beds is extremely low, and the accurate measurement of the permeability of the shale or coal beds is the current technical difficulty. In addition, the measurement of gas permeability and diffusion coefficient of the material is also involved in the analysis and characterization processes of other dense materials such as hydrogen storage materials, catalysts, fuel cell electrodes, building materials and the like.
One type of main method for measuring the gas permeability of a dense material at present is a pressure decay method: processing a sample to be measured into a cylindrical plunger, sealing the cylindrical surface of the cylindrical plunger, manufacturing instantaneous pressure difference between the plunger and a cavity on the upstream and the downstream, measuring and recording the change of the upstream and the downstream pressure, and finally calculating the axial permeability of the sample plunger by analyzing the pressure change curves of the upstream and the downstream cavities. An important factor affecting the accuracy of the measurement of this method is the radial tightness of the sample. At present, a cylindrical surface of a plunger is generally wrapped by a material such as a heat shrinkable tube, the inner surface of the heat shrinkable tube is tightly attached to the cylindrical surface of a sample after heating, and then the pretreated sample is placed in a holder and hydraulic pressure is applied in a radial direction. This type of plunger radial seal method is widely used, but the presence of a small annular gap between the heat shrinkable material and the outer surface of the sample provides an additional bypass path for the gas to seep from the upstream to the downstream of the sample. In the current measuring method, the pressure change caused by the sealing annular seam cannot be accurately distinguished, so that the measuring result of the gas permeability of the sample is higher. In addition, because the sealing materials and sealing processes adopted by experiment operators in the pretreatment stage are different, the quality level of the surface of the sample is different, and the influence of the sealing circular seam on the test result is unstable, the measurement result of the gas permeability of the sample has higher uncertainty.
Disclosure of Invention
In order to solve the technical problem, embodiments of the present invention provide an apparatus and a method for measuring gas permeability of a dense material.
In order to achieve the purpose, the technical scheme of the invention is realized as follows:
the embodiment of the invention provides a gas permeability measuring device for a compact material, which comprises:
an air source device is arranged on the air source device,
the air inlet pipeline is communicated with the air source device;
the upstream cavity is communicated with the gas source device through the gas inlet pipeline;
the downstream cavity is communicated with the gas source device through the gas inlet pipeline;
an upstream pressure sensor connected to the upstream cavity to measure pressure within the upstream cavity;
a downstream pressure sensor connected to the downstream cavity to measure pressure within the downstream cavity;
a holder for holding a test sample assembly and providing a radial seal for the test sample assembly, the holder being located between and in communication with the upstream and downstream cavities, respectively;
a piston pendulum mechanism comprising a first piston and a second piston, the first piston being connected to the upstream cavity and the second piston being connected to the downstream cavity, the first piston and the second piston moving synchronously to vary the volume in the upstream cavity and the volume in the downstream cavity accordingly, and the total volume of the upstream cavity, the holder and the downstream cavity remaining constant;
one end of the air outlet pipeline is communicated with the upstream cavity or the downstream cavity; and
and the vacuum pump is communicated with the other end of the gas outlet pipeline.
Further, the piston swing mechanism also comprises an actuating mechanism;
the first piston and the second piston are respectively connected with one executing mechanism, and the two executing mechanisms are driven synchronously; or
The piston swing mechanism further comprises a rigid connecting structure, and the rigid connecting structure is connected with the first piston and the second piston; the actuating mechanism is connected with the rigid connecting structure so as to drive the first piston and the second piston to synchronously move through the rigid connecting structure.
Further, the upstream cavity and the downstream cavity have the same cross-sectional shape and the same cross-sectional size.
Further, the gas permeability measuring apparatus further includes:
an intake valve disposed on the intake pipe;
the exhaust valve is arranged on the exhaust pipe; and
the isolation valve is arranged on the air inlet pipe and positioned between the upstream cavity and the downstream cavity so as to cut off or communicate the upstream cavity and the downstream cavity.
Further, the gas permeability measuring apparatus further includes: a confining pressure device connected with the holder to enhance a radial seal against a test sample in the test sample assembly.
Further, the gas permeability measuring apparatus further includes: the constant temperature device comprises a constant temperature cavity, and the constant temperature cavity can at least contain the upstream cavity, the downstream cavity and the clamp.
The embodiment of the invention also provides a measuring method, which is used for testing by using any one of the gas permeability measuring devices, and the measuring method comprises the following steps:
at least the upstream cavity, the downstream cavity, the gripper, the air inlet pipeline and the air outlet pipeline are vacuumized by the vacuum pump;
increasing the pressure within the upstream chamber, the downstream chamber, and the holder to an initial pressure using the gas supply;
disturbing the first piston or the second piston, changing the volumes in the upstream cavity and the downstream cavity, measuring and recording a first pressure change result of the upstream pressure sensor along with the change of time to obtain a first pressure change curve, and measuring and recording a second pressure change structure of the downstream pressure sensor along with the change of time to obtain a second pressure change curve;
and judging the sealing quality of the test sample according to the initial pressure, the first pressure change curve and the second pressure change curve, and calculating the permeability of the test sample.
Further, the measurement method further includes:
repeating at least once the following steps:
disturbing the first piston or the second piston, changing the volumes in the upstream cavity and the downstream cavity again, measuring and recording a first pressure change result of the upstream pressure sensor along with the change of time to obtain a first pressure change curve, and measuring and recording a second pressure change structure of the downstream pressure sensor along with the change of time to obtain a second pressure change curve;
calculating the permeability of the test sample according to the initial pressure, the first pressure change curve and the second pressure change curve;
and the repeatedly obtained permeability and the previously obtained permeability are averaged to calculate the average.
Further, in the calculating of the permeability of the test sample, the measuring method further includes:
and calculating the permeability of the test sample according to the pressure distribution in the test sample, the pressure distribution in the seal ring seam of the test sample, the first pressure curve and the second pressure curve.
Further, the time when the first pressure profile and the second pressure profile intersect is denoted as t ', the pressure at the intersection is denoted as p', and the initial pressure is denoted as p0At time t', from said p0The size of p', the volume of the sealing ring seam and the size of pAnd testing the pore volume of the sample, and judging the sealing quality of the test sample.
Embodiments of the present invention provide an apparatus and a method for measuring gas permeability of a dense material, which are capable of producing a pressure difference required for pressure attenuation in the form of piston oscillation by arranging pistons (i.e., a first piston and a second piston) capable of moving synchronously in an upstream chamber and a downstream chamber. The system pressure can be judged to finally return to the initial pressure without knowing the accurate porosity and visual volume of the sample; and furthermore, the condition of the internal pressure recovery of the test sample can be accurately judged through the pressure change condition of the upstream cavity and the downstream cavity, the radial sealing quality of the test sample is determined, a data curve is provided for a related mathematical model, the contribution of the sealing circular seam to seepage is quantitatively eliminated, and the uncertainty of the permeability measurement of the test product is reduced.
Drawings
FIG. 1 is a schematic view of a gas permeability measurement apparatus according to an embodiment of the present invention;
FIG. 2 is a schematic view of a plunger sample and a sealing ring seam according to one embodiment of the present invention;
FIG. 3 is a graph of pressure in an upstream chamber and pressure in a downstream chamber over time according to an embodiment of the invention;
FIG. 4a is a graph showing the time course of the pressure distribution inside the test specimen according to one embodiment of the present invention, in which the time course of the piston swing is shown;
FIG. 4b is a graph of the pressure distribution within the test specimen over time, showing the condition at time t', according to one embodiment of the present invention;
FIG. 4c is a graph showing the time-dependent change in the pressure distribution inside the test specimen, according to one embodiment of the present invention, wherein the pressure returns to the initial value.
Reference numerals:
1-gas source device; 2-an air inlet valve; 3-an isolation valve, 4-an exhaust valve, 5-a confining pressure device, 6-a clamper, 7-a piston swing mechanism, 8-an actuating mechanism, 9-an upstream pressure sensor, 10-a downstream pressure sensor, 11-a vacuum pump, 12-a constant temperature device, 13-an upstream cavity and 131-a first piston; 14-a downstream cavity; 141-a second piston; 15-an air inlet line; 16-a gas outlet pipeline; 110-a heat shrink material; a sample 120; sealing the annular seam 130.
Detailed Description
In order to make the objects, 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 drawings of the embodiments of the present invention. Those skilled in the art will appreciate that the drawings are not necessarily drawn to scale. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention, belong to the scope of protection of the invention.
In the description of the present invention, it is to be understood that the directions or positional relationships indicated by the terms "upper", "lower", "inside", "outside", and the like are based on the directions or positional relationships shown in fig. 1, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and thus, should not be construed as limiting the present invention.
The embodiment of the invention provides a gas permeability measuring device for a compact material, which comprises a gas source device 1, a gas inlet pipeline 15, an upstream cavity 13, a downstream cavity 14, an upstream pressure sensor 9, a downstream pressure sensor 10, a clamp 6, a piston swing mechanism 7, a gas outlet pipeline 16 and a vacuum pump 11.
Specifically, as shown in fig. 1, the intake line 15 communicates with the air supply device 1; the upstream cavity 13 is communicated with the air source device 1 through an air inlet pipeline 15; the downstream cavity 14 is communicated with the air source device 1 through an air inlet pipeline 15; the upstream pressure sensor 9 is connected to the upstream chamber 13 to measure the pressure inside the upstream chamber 13; the downstream pressure sensor 10 is connected to the downstream cavity 14 to measure the pressure within the downstream cavity 14; the clamp 6 is used for placing a test sample assembly and providing radial sealing for the test sample assembly, and the clamp 6 is positioned between the upstream cavity 13 and the downstream cavity 14 and is respectively communicated with the upstream cavity 13 and the downstream cavity 14; the piston swing mechanism 7 comprises a first piston 131 and a second piston 141, the first piston 131 is connected with the upstream cavity 13, the second piston 141 is connected with the downstream cavity 14, the first piston 131 and the second piston 141 move synchronously to change the volume in the upstream cavity 13 and the volume in the downstream cavity 14 correspondingly, and the total volume of the upstream cavity 13, the clamper 6 and the downstream cavity 14 is kept unchanged; one end of the gas outlet pipeline 16 is communicated with the upstream cavity 13 or the downstream cavity 14; the vacuum pump 11 communicates with the other end of the outlet line 16.
Without limitation, as shown in FIG. 2, the test specimen assembly of the present invention includes a plunger-like specimen 120 and a heat shrink material 110 located outside the specimen 120, with a sealing annular seam 130 existing between the heat shrink material 110 and the specimen 120. The sample 120 may be a dense material.
The pressure sensors are used to record the pressure in the respective upstream 13 or downstream 14 chamber, respectively.
The embodiment of the present invention provides a piston swing type permeability measuring apparatus, which can make the pressure difference required for pressure attenuation in the form of piston swing by arranging pistons (i.e., the first piston 131 and the second piston 141) capable of moving synchronously in the closed upstream chamber 13 and the closed downstream chamber 14 in the conventional pressure attenuation system. Therefore, the system pressure can be judged to be finally returned to the initial pressure without knowing the accurate porosity and visual volume of the sample 120; furthermore, the condition of pressure recovery inside the sample 120 can be accurately judged through the pressure change of the upstream cavity 13 and the downstream cavity 14, the quality of radial sealing of the sample 120 is determined, a data curve is provided for a relevant mathematical model, the contribution of the sealing annular seam 130 to seepage is quantitatively eliminated, and the uncertainty of permeability measurement of the compact sample 120 is reduced.
In addition, the gas permeability measuring device provided by the embodiment of the invention can allow a tester to repeatedly drive the piston swing mechanism 7, so that a repeatability experiment can be conveniently carried out, and the random error of the test can be reduced; or by adjusting the amplitude of the piston swing mechanism, the seepage process under different initial pressure differences can be manufactured so as to research the seepage condition of the sample 120 under different working conditions.
Further, the piston pendulum mechanism 7 further includes an actuator 8. The actuator 8 is used to drive the movement of the first piston 131 and the second piston 141. It will be appreciated that the first piston 131 fits within the upstream chamber 13 and seals properly against the inner surface of the upstream chamber 13. A second piston 141 and a downstream chamber 14 are also provided.
The actuator 8 may be selected from a power source and a transmission mechanism well known to those skilled in the art. Including but not limited to, cylinder guides, motor-screw guides, etc.
In some embodiments of the present invention, the first piston 131 and the second piston 141 are each connected to one actuator 8, and the two actuators 8 are driven synchronously.
Alternatively, in other embodiments of the present invention, the gas permeability measuring device comprises only one actuator 8, and the piston pendulum mechanism 7 further comprises a rigid connecting structure connecting the first piston 131 and the second piston 141; the actuator 8 is connected to the rigid connection structure to drive the first piston 131 and the second piston 141 to move synchronously through the rigid connection structure. The rigid connection structure can further ensure the synchronism of the movement of the first piston 131 and the second piston 141. In particular, the rigid connection structure may be a rigid rod or the like as is well known to those skilled in the art.
In some embodiments of the invention, the upstream cavity 13 and the downstream cavity 14 have the same cross-sectional shape and the same cross-sectional size.
For example: the upstream cavity 13 and the downstream cavity 14 have the same structure, and the cross-sectional sections of the upstream cavity 13 and the downstream cavity 14 have the same shape and area. The first piston 131 and the second piston 141 are also of the same specification.
To better control the gas permeability measuring device, in some embodiments of the invention, the gas permeability measuring device further comprises: an inlet valve 2, an exhaust valve 4 and an isolation valve 3.
As shown in fig. 1, an intake valve 2 is provided on the intake pipe; the exhaust valve 4 is arranged on the exhaust pipe; the isolation valve 3 is provided on the intake pipe between the upstream chamber 13 and the downstream chamber 14 to cut off or communicate the upstream chamber 13 and the downstream chamber 14.
In other embodiments of the invention, the isolation valve 3 may not be provided.
In some embodiments of the present invention, the gas permeability measuring apparatus may further include: and the confining pressure device 5, wherein the confining pressure device 5 is connected with the clamp 6 to strengthen the radial sealing of the test sample 120 in the test sample assembly.
As shown in fig. 1, the confining pressure device 5 is used to provide liquid confining pressure for the holder 6, enhance the radial sealing of the plunger sample 120 or simulate the confining pressure environment in which the sample 120 is actually located.
In other embodiments of the present invention, the gas permeability measuring apparatus further comprises: a thermostatic device 12, the thermostatic device 12 comprising a thermostatic chamber capable of housing at least an upstream chamber 13, a downstream chamber 14 and the gripper 6.
When the above-described intake valve 2, exhaust valve 4 and isolation valve 3 are provided, the upstream chamber 13, downstream chamber 14, holder 6, intake valve 2, exhaust valve 4 and isolation valve 3 may all be placed within the thermostatic device 12. The constant temperature device 12 and the confining pressure device 5 are arranged, so that the stability of the measuring environment can be further ensured, and the accuracy of the test result is improved.
In summary, the gas permeability measuring apparatus according to the embodiment of the present invention provides a piston oscillation type gas permeability measuring apparatus for a dense material, and the apparatus disturbs the system pressure by driving the double pistons moving synchronously, so as to ensure that the system pressure can be declared to gradually return to the initial pressure for any tested sample 120 without knowing the porosity and the apparent volume of the sample 120, and further, the leakage level of the sealing annular seam 130 formed by the compressed material 110 and the sample 120 in the holder 6 is clearly determined according to the actual pressure change curve, thereby providing test data for accurately calculating the permeability of the sample 120.
The embodiment of the invention also provides a measuring method, which is used for testing by using the gas permeability measuring device in any embodiment, and the measuring method comprises the following steps:
s10, at least the upstream cavity 13, the downstream cavity 14, the clamper 6, the air inlet pipeline 15 and the air outlet pipeline 16 are vacuumized by the vacuum pump 11;
s20, increasing the pressure in the upstream cavity 13, the downstream cavity 14 and the clamper 6 to the initial pressure by using the air supply device 1;
disturbing the first piston 131 or the second piston 141, changing the volumes in the upstream cavity 13 and the downstream cavity 14, measuring and recording a first pressure change result of the upstream pressure sensor along with the change of time to obtain a first pressure change curve, and measuring and recording a second pressure change structure of the downstream pressure sensor 10 along with the change of time to obtain a second pressure change curve;
and S30, judging the sealing quality of the test sample 120 according to the initial pressure, the first pressure change curve and the second pressure change curve, and calculating the permeability of the test sample 120.
Further, the measuring method further comprises:
repeating the steps S20 to S30 at least once, and calculating the average of the permeability obtained by repeating and the permeability obtained before.
And the random error can be reduced and the measurement precision can be improved by carrying out multiple tests and carrying out average calculation on the results obtained by each calculation.
Optionally, in the calculating the permeability of the test sample 120, the measuring method further includes:
the permeability of the test specimen 120 is calculated based on the pressure distribution within the test specimen 120, the pressure distribution within the sealed annular seam 130 of the test specimen 120, and the first and second pressure curves.
Further, the time when the first pressure change curve and the second pressure change curve intersect is denoted as t' [ s ]]And the pressure at the intersection is p' [ MPa ]]Initial pressure is denoted as p0[MPa]At time t', according to p0And p', the volume of the sealing annular seam 130 and the pore volume of the test specimen 120, the quality of the seal of the test specimen 120 is judged.
The above-described specific calculation method, and the method of judging the sealing quality of the test specimen 120 refer specifically to the following specific examples.
The method for measuring gas permeability according to the present invention is further explained below with a specific example,
firstly, pumping the whole system to vacuum by using a vacuum pump 11; then the pressure of the upstream cavity 13, the downstream cavity 14 and the clamper 6 is increased to p by using the high-pressure gas source device 10；
The air inlet valve 2, the isolation valve 3 and the exhaust valve 4 are all in a closed state, the upstream pressure sensor 9 and the downstream pressure sensor 10 are in a recording state, the first piston 131 is driven to swing and displace, and the volume of the upstream cavity 13 is reduced by delta V [ unit m ]3]The downstream cavity 14 volume is synchronously increased by Δ V. The volume change amount Δ V is calculated by multiplying the sectional areas of the upstream chamber 13 and the downstream chamber 14 by the movement displacement of the piston pendulum mechanism 7.
The measurement results of the upstream pressure sensor 9 and the downstream pressure sensor 10, i.e. the pressure change curves of the upstream cavity 13 and the downstream cavity 14 are respectively denoted as pA(t) and pB(t) of (d). Recording the pressure curve pA(t) and pB(t) until the pressures of the upstream chamber 13 and the downstream chamber 14 become p again0. Calculating according to the pressure change curve according to the following method to obtain the gas permeability of the compact material:
note pA(t) and pB(t) the initial pressure of the two curves is pA0And pB0The time at which the two curves intersect is t' [ unit s ]]The pressure is p' [ MPa ]]. The cross-sectional area of the dense material is marked as A [ unit m ]2]Length of l [ unit m ]]Permeability of k [ unit m ]2]Porosity of epsilon [ unit 1 ]]The density of the test gas is rho [ unit kg/m ]3]Viscosity is μ [ unit Pa.s ]]The compression factor is Z [ unit 1 ]]Isothermal compressibility factor of cg[ unit Pa)-1](ii) a Let us note that the permeability of the sealing circumferential seam 130 around the plunger sample 120 is ksl[ unit m)2]Porosity of epsilonsl[ Unit 1)]Cross-sectional area Asl[ unit m)2]. The spatial position of the dense sample 120, the sealing bead 130 in the holder 6 is shown in fig. 2.
During the 0-t' time period, the pressure profile p (x, t) within the sample 120 (as shown in FIG. 3), the pressure profile p within the seal ring seam 130sl(x, t), pressure curve pA(t) and pB(t) (as shown in fig. 4a to 4 c) satisfies the following system of differential equations I:
boundary conditions:
initial conditions:
p(x，0)＝psl(x，0)＝p0，0＜x＜l
p(0，0)＝psl(0，0)＝pA(0)，p(l，0)＝psl(l，0)＝pB(0)
at time t ', the pressures in the upstream chamber 13 and the downstream chamber 14 are simultaneously p ', if p ' is still greater than p0Indicating that the internal pressure of either the sample 120 or the sealing annular seam 130 is not yet balanced, if the volume of the sealing annular seam 130 is much smaller than the pore volume of the sample 120, it can be determined that the pressure in the sample 120 is not yet balanced. Pressure curve pA(t) and pB(t) are combined into a curve (see FIG. 3) in which the pressure profile p (x, t) within the sample 120, the pressure curve pA(t) and pB(t) satisfies the following differential equation set II:
boundary conditions:
p(0，t′)＝p(l，t′)＝pA(t′) (8)
at time t ', if the pressures p' and p0Equal or within 5% of each other, very close, and the volume of the seal ring 130 is much less than the pore volume of the sample 120, then the radial seal to the sample 120 may be considered appropriate, and the permeability k of the seal ring 130 in equations (1) - (4) may be considered to be adequateslIs 0.
In equations (1) - (8), the unknown parameters include k,
Aslkslthree of them. By combining an optimization algorithm and a partial differential equation numerical solution, three unknown parameters can be fitted and determined, and further the gas permeability k of the dense sample 120 can be determined.
Optionally, the pressure is returned to the initial pressure p inside the device0Then, the piston can be driven to swing back to the initial position, the pressure change curves of the upstream cavity 13 and the downstream cavity 14 are recorded again, and a new pressure curve p can be obtained againA(t) and pB(t) of (d). Optionally, the permeability k is obtained by fitting again by using the permeability calculation method, and is averaged with the first measurement result, so that the random error is reduced.
Other structures and operations of the gas permeation mechanism according to the embodiment of the present invention are understood and easily accomplished by those skilled in the art, and thus will not be described in detail.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention.
Claims (10)
1. A gas permeability measuring device for a dense material, the gas permeability measuring device comprising:
an air source device is arranged on the air source device,
the air inlet pipeline is communicated with the air source device;
the upstream cavity is communicated with the gas source device through the gas inlet pipeline;
the downstream cavity is communicated with the gas source device through the gas inlet pipeline;
an upstream pressure sensor connected to the upstream cavity to measure pressure within the upstream cavity;
a downstream pressure sensor connected to the downstream cavity to measure pressure within the downstream cavity;
a holder for holding a test sample assembly and providing a radial seal for the test sample assembly, the holder being located between and in communication with the upstream and downstream cavities, respectively;
a piston pendulum mechanism comprising a first piston and a second piston, the first piston being connected to the upstream cavity and the second piston being connected to the downstream cavity, the first piston and the second piston moving synchronously to vary the volume in the upstream cavity and the volume in the downstream cavity accordingly, and the total volume of the upstream cavity, the holder and the downstream cavity remaining constant;
one end of the air outlet pipeline is communicated with the upstream cavity or the downstream cavity; and
and the vacuum pump is communicated with the other end of the gas outlet pipeline.
2. The gas permeability measurement device of claim 1, wherein the piston pendulum mechanism further comprises an actuator;
the first piston and the second piston are respectively connected with one executing mechanism, and the two executing mechanisms are driven synchronously; or
The piston swing mechanism further comprises a rigid connecting structure, and the rigid connecting structure is connected with the first piston and the second piston; the actuating mechanism is connected with the rigid connecting structure so as to drive the first piston and the second piston to synchronously move through the rigid connecting structure.
3. The gas permeability measurement device of claim 1, wherein the upstream and downstream cavities have the same cross-sectional shape and the same cross-sectional size.
4. The gas permeability measurement device according to claim 1, further comprising:
an intake valve disposed on the intake pipe;
the exhaust valve is arranged on the exhaust pipe; and
the isolation valve is arranged on the air inlet pipe and positioned between the upstream cavity and the downstream cavity so as to cut off or communicate the upstream cavity and the downstream cavity.
5. The gas permeability measurement device according to claim 1, further comprising: a confining pressure device connected with the holder to enhance a radial seal against a test sample in the test sample assembly.
6. The gas permeability measurement device according to claim 1, further comprising: the constant temperature device comprises a constant temperature cavity, and the constant temperature cavity can at least contain the upstream cavity, the downstream cavity and the clamp.
7. A measurement method characterized by performing measurement using the gas permeability measurement apparatus according to any one of claims 1 to 6, the measurement method comprising:
at least the upstream cavity, the downstream cavity, the gripper, the air inlet pipeline and the air outlet pipeline are vacuumized by the vacuum pump;
increasing the pressure within the upstream chamber, the downstream chamber, and the holder to an initial pressure using the gas supply;
disturbing the first piston or the second piston, changing the volumes in the upstream cavity and the downstream cavity, measuring and recording a first pressure change result of the upstream pressure sensor along with the change of time to obtain a first pressure change curve, and measuring and recording a second pressure change structure of the downstream pressure sensor along with the change of time to obtain a second pressure change curve;
and judging the sealing quality of the test sample according to the initial pressure, the first pressure change curve and the second pressure change curve, and calculating the permeability of the test sample.
8. The measurement method according to claim 7, further comprising:
repeating at least once the following steps:
disturbing the first piston or the second piston, changing the volumes in the upstream cavity and the downstream cavity again, measuring and recording a first pressure change result of the upstream pressure sensor along with the change of time to obtain a first pressure change curve, and measuring and recording a second pressure change structure of the downstream pressure sensor along with the change of time to obtain a second pressure change curve;
calculating the permeability of the test sample according to the initial pressure, the first pressure change curve and the second pressure change curve;
and the repeatedly obtained permeability and the previously obtained permeability are averaged to calculate the average.
9. The measurement method according to claim 7, wherein in calculating the permeability of the test sample, the measurement method further comprises:
and calculating the permeability of the test sample according to the pressure distribution in the test sample, the pressure distribution in the seal ring seam of the test sample, the first pressure curve and the second pressure curve.
10. The method of measurement according to claim 7, wherein the time at which the first pressure profile and the second pressure profile intersect is denoted t ', the pressure at which the first pressure profile and the second pressure profile intersect is denoted p', and the initial pressure is denoted p0At time t', from said p0And judging the sealing quality of the test sample according to the size of the p', the volume of the sealing annular seam and the pore volume of the test sample.
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| TWI818363B (en) * | 2021-11-01 | 2023-10-11 | 行政院原子能委員會核能研究所 | Apparatus for measuring gas permeability of porous material |
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