CN105388088A - Test apparatus for characterizing condensation characteristic of foam fluid by loss flow time, and method thereof - Google Patents

Abstract

The invention discloses a test device and method for characterizing the coagulation characteristics of foam fluid by using the lost flow time. The device of the present invention includes a test frame and a measuring container; the test frame includes a base plate, on which two support plates are vertically fixed, and the two support plates form an angle of 90 degrees to each other and are fixed on the base plate through the two support plates. A leveling screw and a leveling nut are respectively provided at the four corners of the measuring vessel; the measuring vessel is a cuboid with an open upper end, and an initial line is drawn in the middle of the wall of the measuring vessel to measure a vertical side of one side of the vessel The line connecting the bottom end to the top of the other vertical side is used as the horizontal line. The present invention also provides a method and steps for testing the lost-flow time of the foam fluid to be tested by using the above-mentioned device. Using the device and method of the present invention can obtain the coagulation time of the tested foam fluid, that is, the lost flow time. The testing device of the invention has the advantages of simple structure, ingenious conception, convenient operation and accurate result of the testing method.

Description

Test device and method for characterizing foam fluid coagulation characteristics by lost flow time

technical field

The invention belongs to a test device and method for the coagulation characteristic of foam fluid, in particular to a test device and method for characterizing the coagulation characteristic of foam fluid by using lost flow time.

Background technique

Foam fluid has good fracture seepage and upward accumulation characteristics and has excellent heat insulation ability after solidification, so it has become the main technical means for preventing coal spontaneous combustion in mines and coal fields in the future. Because the seepage and diffusion form and range of cement-based foam fluid largely depend on its setting characteristics, and the pouring volume and pouring range in cast-in-place construction also depend on its setting time, so the setting characteristics of cement-based foam fluid are The most important factor to consider. But for cement-based foam fluid, there are very few studies on the determination method of its setting time. For example, the "Experimental Research on the Setting Time of Foamed Concrete" proposed by domestic scholar Fan Lilong mainly focuses on the influence of the amount of foaming agent on the setting time. The setting time is measured using the method of measuring the setting time of concrete, namely the penetration resistance method. The method of determining the setting time of cement using the initial setting needle and final setting needle of the Vicat instrument provided in the national cement standard GB/T1346-2011 is not suitable for porous and heterogeneous foam fluids, because when the test needle penetrates into the foam fluid When it is in the material, it will pass through the foam space and the liquid film on the hole wall, and the foam space is air, and the resistance to the penetrating needle is basically zero, resulting in errors in the measurement data. The industry standard JG/T266-2011 of foam concrete only provides the consistency standard of foam concrete, and does not give the standard for the determination of setting time. Therefore, it is necessary to propose an accurate and effective method for determining the coagulation time of foam fluid.

Contents of the invention

A first object of the present invention is to provide a test device for characterizing the coagulation characteristics of foamed fluids in terms of lost flow time. In order to solve the above problems, by analyzing the microcosmic mechanism of cement-based foam fluid, it is concluded that the hydration reaction of a single foam body during the coagulation process promotes the rapid coagulation of the foam cell wall, the stability of the cells is enhanced, and the structure is not easily deformed, which eventually leads to The flow resistance of a single foam increases and the flow is difficult. As a whole, the hydration products on the foam cell walls increase and precipitate out as a whole, bridging between different particles, and the individual foam particles are connected into one piece, flowing as a whole, hindering each other, and finally losing fluidity slowly, reaching a coagulation state. For this reason, we conduct experiments through the device of the present invention and propose a loss fluidity time (Lossfluiditytime, LFT) index as a characterization of the coagulation characteristics of the inorganic solidified foam fluid. LFT represents the time required for the foam fluid to reach the no-flow state.

The first object of the present invention is achieved by the following technical scheme: the test device for characterizing the coagulation characteristics of foam fluid with the lost flow time includes a test frame and a measuring container; There are two support plates fixed to each other, and the two support plates are fixed on the bottom plate through the two support plates at an angle of 90 degrees to each other. A leveling screw and a leveling nut are respectively provided on the four corners of the bottom plate; The above-mentioned measuring container is a cuboid with an open upper end, and an initial line is drawn in the middle of the wall of the measuring container, and the line connecting the bottom of one vertical side on one side of the measuring container to the upper part of the other vertical side is used as the horizontal line; When the measuring container is placed within the 90-degree angle formed by the two support plates, the volume of the foam fluid to be measured at the initial line when the measuring container is placed horizontally flows slowly under the action of gravity, and the top level of the foam fluid is just right when it flows to the horizontal. Stay at the horizon.

Specifically, the bottom plate, support plate, support plate and measurement container of the test frame are all made of plexiglass material.

Specifically, the two support plates are fixed on the base plate at an angle of 60 degrees and 30 degrees with the base plate respectively; the length, width and height of the measuring container are respectively 10 cm, 10 cm and 23 cm, and the initial line is located at At a height of 10cm from the bottom of the measuring container, the horizontal line is located on the diagonal of one side of the measuring container.

A second object of the present invention is to provide a test method based on the above-mentioned testing device for characterizing the coagulation characteristics of the foam fluid with the lost flow time, the method comprises the steps in the following order:

(1) Adjust the leveling screws on the four corners of the bottom plate to make the device level, and then inject a certain porosity of cement-based foam fluid into the measuring container, so that the volume of the foam fluid reaches the initial line;

(2) Start counting from the end of foam fluid preparation, after a certain moment T _i , the measuring container is tilted to be placed in the 90 degree angle formed by the support plate, and start timing simultaneously; The prepared cement-based foam fluid in the measuring container will be Due to the downward flow of gravity, it finally becomes horizontal or close to the level and makes the top level of the cement-based foam fluid spread to the level line of the measuring container; when the cement-based foam fluid flows to the level line, stop timing, and then time is t _i , and it is called the leveling time, the measuring container after reaching the leveling is taken off from the support plate and placed upright, so that the cement-based foam fluid returns to the initial state;

(3) At the same time interval T _i+1 , put the measurement container on the support plate again for timing, and repeat the previous operation to get another flat time t _i+1 ; because the cement-based foam fluid progresses over time The reaction will gradually condense, and the time required for each level will increase; after obtaining multiple groups (t, T), draw the tT curve under the porosity, and fit the curve, and get the curve after fitting There is an asymptote, because at the same time interval, t will increase infinitely with time, tending to infinity, we can consider that the cement-based foam fluid has condensed when the time to reach the horizon is infinite, so the asymptote corresponds to The time T _LF is the time when the cement-based foam fluid loses its fluidity, abbreviated as LFT.

The test device of the present invention is simple in structure, ingenious in design, easy to operate and accurate in test method, and its innovations and beneficial effects are mainly reflected in the following points:

(1) Use the time corresponding to the asymptote obtained by repeatedly tilting the container at the same time interval and performing function fitting on the time when the foam fluid reaches the flat line each time as the coagulation time of the foam fluid, and the coagulation time is called Loss of flow time (LFT), so the test results are more accurate.

(2) Use transparent plexiglass that is easy to observe and operate as the experimental device, which is more convenient and scientific than other testing methods.

Description of drawings

Fig. 1 is a schematic structural diagram of a device according to an embodiment of the present invention.

FIG. 2 is a top view of FIG. 1 .

Fig. 3 is a schematic diagram of the experimental flow of the present invention.

Fig. 4 is a function fitting diagram of the present invention.

detailed description

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

Referring to FIG. 1 and FIG. 2 , the device of this embodiment includes a test rack 1 and a measuring container 2 . The test frame 1 includes a base plate 103, on which two support plates 102 are vertically fixed, and the two support plates 101 are fixed on the base plate 103 through the two support plates 102 at an angle of 90 degrees to each other, and the left and right support plates 101 forms an included angle of 60 degrees and 30 degrees with the bottom plate, so that the foam fluid to be measured in the measuring container 2 containing the foam fluid to be measured can flow to the horizontal line 203 in this embodiment. A leveling screw 105 and a leveling nut 104 are respectively arranged on the four corners of the bottom plate 103, and four pairs of leveling nuts 104 and leveling screws 105 cooperate with each other to make the whole device level. The bottom plate 103, the support plate 102, and the support plate 101 of the above-mentioned test frame 1 are all made of plexiglass material. The measuring container 2 is a cuboid whose length, width, and height are 10cm, 10cm, and 23cm respectively, and its upper end is open. The measuring container 2 is also made of plexiglass material. An initial line 202 is inscribed on the wall at a height of 10 cm from the bottom surface 201 of the measuring container 2, and its function is to limit the volume of the foam fluid to be measured. The diagonal line on one side of the measuring container 2 is taken as the horizontal line 203, and its function is to detect whether the fluidity of the foam fluid is lost and to record the flow time of the foam fluid. When the measuring container 2 is placed in the 90-degree angle formed by the two support plates 101, when the measuring container 2 is placed horizontally, the volume of the foam fluid to be measured at the initial line 202 flows slowly under the action of gravity, and finally flows to the horizontal The top level of the foamy fluid rests exactly at the horizon 203 .

Referring to Fig. 3, Fig. 4, based on the measurement method of the measuring device of the foam fluid coagulation characteristic characterized by the lost flow time, the determination of the lost flow time of the foam fluid to be tested is completed through the following steps:

Step 1: Adjust the leveling screw 105 to make the device level, and then inject cement-based foam fluid with a density of 400g/cm ³ into the cuboid measuring container 2, so that the volume of the slurry reaches the initial line 202.

Step 2: start timing from the end of the preparation, place the test frame 1 on a horizontal plane after 2 minutes, then place the measuring container 2 obliquely on the support 101, and start timing at the same time at an angle of 30 degrees with the horizontal; The prepared cement-based foam fluid will flow downward due to gravity, as shown in ①→②→③→④→⑤→⑥ in FIG. When the cement-based foam fluid flows to the level line 203, stop counting, and this time counting is 2 minutes, which is the first "time to level". The measured container 2 after being leveled is taken off from the support 101 and placed upright, so that the cement-based foam fluid can be restored to its original state.

Step 3: After the same time interval of 2 minutes, put the measuring container 2 on the bracket 101 again for timing, and repeat the previous operation to obtain the second "equivalent time", 2.25 minutes. Then, the above operations are repeated to obtain multiple groups (t, T). The tT curve under the porosity is drawn by Matlab, and the curve is fitted. After fitting, the curve equation is t=19.2/(14-T)+0.48, and it can be found that the equation has an asymptote T=14 , because at the same time interval, t will increase infinitely with time and tend to infinity, we can consider that the time to reach the horizon is infinite, indicating that the inorganic solidified foam has condensed, so the time T _LF = 14 corresponding to the asymptote is The loss of fluidity time of the cement-based foam fluid under the porosity, referred to as LFT.

The basic principles, main features and advantages of the invention have been shown and described above. Those skilled in the industry should understand that the present invention is not limited by the above-mentioned embodiments. What are described in the above-mentioned embodiments and the description only illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will also have Variations and improvements are possible, which fall within the scope of the claimed invention. The protection scope of the present invention is defined by the appended claims and their equivalents.

Claims (4)

1., to lose a proving installation for flowing time characterization of foam fluid condenses characteristic, it is characterized in that: it comprises testing jig and measuring vessel; Described testing jig comprises base plate, and base plate is vertically fixed with two pieces of back up pads, and two pieces of supporting plates are mutually an angle of 90 degrees and are fixed on base plate by described two pieces of back up pads, and four angles of base plate are respectively equipped with a leveling serew and a leveling nut; Described measuring vessel is rectangular parallelepiped, its upper end open, has an initial line in the wall center score of measuring vessel, using the line on a vertical edge bottom to another vertical edge top of measuring vessel one side as to horizontal line; When measuring vessel is positioned in an angle of 90 degrees that two pieces of supporting plates are formed, the aerated fluid to be measured being positioned at initial line place volume during measuring vessel horizontal positioned slowly flows under gravity, and when finally flowing to level, aerated fluid top levels just in time rests on to horizontal line place.

2. according to claim 1 with the proving installation losing flowing time characterization of foam fluid condenses characteristic, it is characterized in that: the base plate of described testing jig, back up pad, supporting plate and measuring vessel all adopt pmma material to make.

3. according to claim 1 with the proving installation losing flowing time characterization of foam fluid condenses characteristic, it is characterized in that: described two pieces of supporting plates become 60 degree and 30 degree of angles to be fixed on base plate by back up pad respectively with base plate; The length of described measuring vessel is respectively 10cm, 10cm, 23cm, and initial line is positioned at the At The Height apart from measuring vessel bottom surface 10cm, is positioned on the diagonal line of measuring vessel one side to horizontal line.

4. based on described in claim 1 to lose a method of testing for the proving installation of flowing time characterization of foam fluid condenses characteristic, it is characterized in that comprising the step of following order:

(1) leveling serew adjusted on base plate four angles makes device be in level, then the cement based aerated fluid of certain porosity is injected measuring vessel, makes aerated fluid volume reach initial line place;

(2) timing, at a time T from aerated fluid preparation terminates _iafter by measuring vessel slant setting in an angle of 90 degrees that supporting plate is formed, start timing simultaneously; The cement based foam stream that prepared in measuring vessel is known from experience to take advantage of a situation because of gravity and is flowed downward, finally present level or close to level and make the top levels of cement based aerated fluid spread to measuring vessel to horizontal line place; Stop timing when cement based aerated fluid flow to during horizontal line place, now timing is t _i, and be referred to as between at ordinary times, near flat after measuring vessel lift down from supporting plate and just put, cement based aerated fluid is restPosed;

(3) in same time interval T _i+1in the moment, again measuring vessel is put in timing on supporting plate, operates before repetition, will be obtained another to t between at ordinary times _i+1; Because cement based aerated fluid condenses gradually along with the carrying out of time can react, to increase to the flat required time at every turn; Obtaining many groups of (t, T) after, draw the t-T curve under this porosity, and matching is carried out to curve, show after matching that curve has bar asymptotic line, because of under same time interval, t increases in time and will infinitely increase, be tending towards infinite, we can think that the time to horizontal line of arriving is that cement based aerated fluid condenses time infinitely great, therefore the moment T that asymptotic line is corresponding _lFbe the time lost flowability of cement based aerated fluid, be called for short LFT.