CN115655769A - Heat exchange experiment system and experiment method for middle-deep layer double-pipe heat exchanger - Google Patents
Heat exchange experiment system and experiment method for middle-deep layer double-pipe heat exchanger Download PDFInfo
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Abstract
A heat exchange experiment system and an experiment method for a middle-deep layer sleeve heat exchanger belong to the technical field of geothermal energy utilization. The problems that in an existing middle-deep layer heat exchange experiment mode, the distribution condition of a stratum is not really simulated, and a buried pipe for testing is not in an even geothermal gradient environment, so that an experiment result is inaccurate, and theoretical support and basis cannot be provided for construction practice are solved. The invention adopts different types of heat exchanger models, adopts a single-pipe heat exchanger model to test the heat exchange effect of a certain circulating medium in two flowing directions, or adopts pipe group heat exchanger models in different arrangement forms to test the heat exchange effect of different pipe group arrangement forms, so as to provide theoretical support and basis for construction practice. The method is mainly used for testing the tube bank heat exchanger buried model or the single tube heat exchanger buried model, calculating the heat exchange quantity of the tube bank heat exchanger buried model or the single tube heat exchanger buried model in the running time and obtaining the soil heat affected radius map when the running is finished.
Description
Technical Field
The invention belongs to the technical field of geothermal wells and geothermal energy utilization, and particularly relates to a heat exchange experiment system and an experiment method for a middle-deep layer sleeve heat exchanger.
Background
The medium-deep layer non-interference heat supply technology is a novel geothermal energy utilization technology which is just emerging in recent years, and is mainly different from a hydrothermal geothermal energy utilization technology in that water is not taken for heat taking, the interference to the underground ecological environment is less, and compared with a shallow layer system, the medium-deep layer system has the main advantages of small occupied area, stable heat source and higher heat exchange efficiency.
The middle-deep layer interference-free heat supply technology combines the advantages of a shallow ground source heat pump and a middle-deep layer hydrothermal type heat supply technology, effectively solves the urgent problems that a shallow buried pipe occupies a large area, a heat source is unstable and a hydrothermal type system damages an ecological system, is one of the leading-edge emerging technologies in the field of geothermal energy utilization, and is behind the engineering practice in the theoretical research of heat exchange of the middle-deep layer heat supply system. In the research of the heat exchange theory of the middle-deep heating system, because the distribution condition of the stratum is not really simulated and the tested buried pipe is not in the uniform geothermal gradient environment, the experimental result is inaccurate, and the theoretical support and basis can not be provided for the construction practice.
Disclosure of Invention
The technical problems to be solved by the invention are as follows: in the conventional middle-deep layer heat exchange experiment mode, the distribution condition of a stratum is not really simulated, and a buried pipe for a test is not in a uniform geothermal gradient environment, so that the experiment result is inaccurate, and theoretical support and basis cannot be provided for construction practice; further provides a heat exchange experiment system and an experiment method for the middle-deep layer double-pipe heat exchanger.
The technical scheme adopted by the invention for solving the technical problems is as follows:
a heat exchange experiment system of a middle-deep layer sleeve heat exchanger comprises a cold region building environment simulation cabin, a buried pipe heat exchanger model, a test sand box, a ground temperature control box, a circulating water mechanism and a data acquisition mechanism; the pipe-embedded heat exchanger model, the test sand box, the ground temperature control box, the circulating water mechanism and the data acquisition mechanism are arranged in the cold-region building environment simulation cabin; the test sand box is arranged on the upper surface of the ground temperature control box and comprises a sand box body with an opening at the upper end and a test stratum consisting of a plurality of layers of soils with different physical parameters distributed from top to bottom; the test stratum is positioned in the sand box body, the buried pipe heat exchanger model is longitudinally inserted in the middle of the test stratum and penetrates through the multilayer soil in the test stratum, the bottom end of the buried pipe heat exchanger model is positioned in the soil at the lowest layer of the test stratum, and the top end of the buried pipe heat exchanger model extends out of the upper surface of the test stratum; the water inlet of the buried pipe heat exchanger model is communicated with the water outlet of the circulating water mechanism, and the water outlet of the buried pipe heat exchanger model is communicated with the water inlet of the circulating water mechanism; the data acquisition mechanism is used for acquiring data.
Furthermore, the ground temperature control box comprises a ground temperature control box body, a constant temperature controller and a plurality of uniformly distributed electric heating tubes, wherein the electric heating tubes are distributed in the ground temperature control box body, and the constant temperature controller is arranged outside the ground temperature control box body and is connected with the electric heating tubes to control the heat productivity of the electric heating tubes.
Furthermore, the circulating water mechanism comprises a high-low temperature cooling and heating integrated machine, a water pump, a water inlet pipe and a water outlet pipe; the water inlet of the water outlet pipe is connected to the water outlet of the high-low temperature cold-hot all-in-one machine, the water outlet of the water outlet pipe is connected to the water inlet of the buried pipe heat exchanger model, the water outlet of the buried pipe heat exchanger model is connected to the water inlet of the water inlet pipe, the water outlet of the water inlet pipe is connected to the water inlet of the high-low temperature cold-hot all-in-one machine, and the water pump is installed on the water outlet pipe.
Furthermore, the data acquisition mechanism comprises a plurality of thermocouples, a flowmeter, two thermometers, a memory, a display and a sensing wire; the thermocouples are longitudinally and uniformly distributed in a test stratum of the test sand box, wherein a row of thermocouples is arranged on the surface of the soil layer on the uppermost layer, a row of thermocouples is arranged between two adjacent soil layers with different physical property parameters, and a row of thermocouples is arranged at the bottom of the soil layer on the lowermost layer; the thermocouples are densely distributed at the positions close to the heat exchanger model of the buried pipe in the radial direction and are sparsely distributed at the positions far away from the heat exchanger model of the buried pipe; one of the thermometers is arranged on the water outlet pipe, and the flowmeter and the other thermometer are arranged on the water inlet pipe along the water flow direction; the thermocouple, the flowmeter, the thermometer, the thermostatic controller and the high-low temperature and cold-hot all-in-one machine are respectively connected with the memory through sensing lines, and data are displayed by the display.
Furthermore, the heat exchanger model is a single-pipe heat exchanger model, which is a buried pipe, the water outlet of the water outlet pipe in the circulating water mechanism is connected to the water inlet of the buried pipe, and the water outlet of the buried pipe is connected to the water inlet of the water inlet pipe.
Furthermore, the buried pipe heat exchanger model is a pipe group buried pipe heat exchanger model and consists of a plurality of buried pipes; the water outlets of the water outlet pipes in the circulating water mechanism are respectively connected with the water inlets of the buried pipes, and the water outlets of the buried pipes are respectively connected with the water inlets of the water inlet pipes; the circulating water mechanism also comprises a water separator and a water collector; the water separator is arranged on the water outlet pipe and behind the water pump, and the water collector is arranged on the water inlet pipe.
Furthermore, each buried pipe comprises an outer layer cavity, an inner layer cavity, an outer water inlet and an inner water outlet; the inner layer cavity is positioned in the outer layer cavity and communicated with the outer layer cavity; the outer water inlet is positioned at the upper end of the buried pipe and is communicated with the outer layer cavity, and the inner water outlet is positioned at the top end of the buried pipe and is communicated with the inner layer cavity.
A method for heat exchange experiments of a middle-deep layer double-pipe heat exchanger comprises the following specific experimental steps:
step 7, setting a determined ground temperature gradient, starting a constant temperature controller to control the heat productivity of the uniformly distributed electric heating pipes, heating water in the box body of the ground temperature control box, and providing a constant ground temperature gradient;
step 8, standing the experimental system, and observing the soil temperature through a display until the soil temperature presents a certain gradient and keeps stable;
step 9, setting a high-low temperature cold and hot water integrated machine to simulate a heat load, and determining the circulating flow and the running time;
step 10, starting a water pump to perform a heat exchange experiment, and storing the temperature, the flow speed, the flow, the ground temperature gradient, the heat load and the soil temperature in the whole operation time by a memory;
and 11, calculating the heat exchange quantity of the heat exchanger model of the buried pipe in the running time, and obtaining a soil heat affected radius diagram when the running is finished.
Further, the step 1 is a tube group buried tube heat exchanger model, and a tube arrangement mode of a plurality of buried tubes is designed; after the step 11 is finished, clearing the soil in the box body of the sand box, determining the next pipe group pipe distribution mode, repeating the steps 1 to 11, and simultaneously ensuring that other conditions except the pipe group pipe distribution mode are kept unchanged; after the experiment of all the pipe group pipe distribution modes is completed, the heat exchange quantity of the pipe group in the running time of different pipe group pipe distribution modes and the soil heat affected radius at the end of running are compared, and the influence result of the pipe group pipe distribution modes on the heat exchange capacity of the pipe group is analyzed.
Further, the step 1 is a single-pipe heat exchanger model; after the step 11 is finished, connecting a water outlet pipe of the circulating water mechanism with an inner water inlet of the buried pipe, connecting an outer water outlet of the buried pipe with a water inlet pipe of the circulating water mechanism, starting a water pump to fill the buried pipe with a circulating medium, repeating the step 5 to the step 11, and simultaneously ensuring that other conditions except the flowing direction of the circulating medium are kept unchanged; after the experiment of two flowing directions of a certain circulating medium is completed, the heat exchange quantity of the two flowing directions of the certain medium in the running time and the soil heat affected radius at the end of running are compared, and the influence result of the flowing direction of the circulating medium on the heat exchange capacity of the tube group is analyzed.
Compared with the prior art, the invention has the following beneficial effects:
1. according to the method, the influence of the heat influence radius and the heat taking quantity of the soil is tested according to the circulation flow, the water inlet temperature, the flow direction, the circulation working medium, the soil heat conductivity coefficient, the ground temperature gradient, the pipe diameters of the inner pipe and the outer pipe, the heat resistance of the inner pipe and the outer pipe, the buried depth, the operation time, the pipe group pipe arrangement mode and the like of the buried pipe heat exchanger model, so that theoretical support and basis are provided for construction practice.
2. This application passes through high low temperature hot and cold water all-in-one reduces and comes from the higher water of the endothermic temperature of pipe laying heat exchanger model in the sand box, and the heat load of simulation heat supply building can guarantee that the heat load is stable, has succinct accuracy, advantage that stability is high.
3. The thermocouple is uniformly arranged in the depth direction of the test sand box, so that the temperature of the soil at different depths can be measured; because the temperature change speed of the sand box soil close to the heat exchanger model is high, and the temperature change of the sand box soil far away from the heat exchanger model is small or constant, the thermocouples densely arranged close to the heat exchanger can measure more accurate soil temperature, and the thermocouples sparsely arranged far away from the heat exchanger can reduce unnecessary measuring points and reduce the calculation amount.
4. The outer wall of the box body of the sand box and the outer wall and the bottom of the box body of the ground temperature control box are subjected to heat preservation and insulation treatment; the soil in the reduction sand box body and the heat dissipation of the hot water in the ground temperature control box body, under the prerequisite of guaranteeing to provide the uniform temperature field for sand box soil, reduce ground temperature control box volume, reduce thermoelectric tube power consumption.
5. Real-time temperature, flow, velocity of flow, ground temperature gradient, heat load and soil temperature can be obtained through data acquisition mechanism in this application, be used for the analysis and the calculation of the soil heat influence radius, the heat transfer volume of pipe laying heat exchanger model show the influence effect of the pipe laying heat exchanger model of each factor.
Drawings
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this application.
Fig. 1 is a schematic view of the overall structure of the present invention.
Fig. 2 is a structural schematic diagram of the buried pipe.
Description of reference numerals: 1-a borehole heat exchanger model; 1-1-pipe burying; 1-1-1-outer layer cavity; 1-1-2-inner cavity; 1-1-3-external water inlet; 1-1-4-inner water outlet; 1-1-5-pipeline; 2-test sand box; 2-1-a sand box body; 2-2-test formation; 3-a ground temperature control box; 3-1-a ground temperature control box body; 3-2-constant temperature controller; 3-3-electric heating tube; 4-a circulating water mechanism; 4-1-high and low temperature cold and hot integrated machine; 4-2-water pump; 4-3-water separator; 4-4-a water collector; 4-5-water inlet pipe; 4-6-water outlet pipe; 5-a data acquisition mechanism; 5-1-thermocouple; 5-2-flow meter; 5-3-thermometer; 6-building an environment simulation cabin in a cold area.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and the following embodiments are used for illustrating the present invention and are not intended to limit the scope of the present invention.
Because the experimental system of this application can adopt single tube heat exchanger of burying pipe model to be used for testing the heat transfer effect of two kinds of flow directions of certain circulating medium, perhaps adopts the tube bank heat exchanger of different arrangement forms model to be used for testing the heat transfer effect that different tube banks arranged the form, so this application carries out detailed description through two embodiments:
example 1: the pipe group heat exchanger model with different arrangement forms is adopted to test the heat exchange effect of different pipe group arrangement forms, referring to fig. 1, the embodiment provides a heat exchange experimental system of a middle-deep layer sleeve heat exchanger for a pipe group heat exchanger, which comprises a cold-region building environment simulation cabin 6, a pipe group heat exchanger model, a test sand box 2, a ground temperature control box 3, a circulating water mechanism 4 and a data acquisition mechanism 5; the pipe-embedded heat exchanger model 1, the test sand box 2, the ground temperature control box 3, the circulating water mechanism 4 and the data acquisition mechanism 5 are arranged in a cold region building environment simulation cabin 6; the test sand box 2 is arranged on the upper surface of the ground temperature control box 3, the pipe group buried pipe heat exchanger model is longitudinally inserted in the middle of the test sand box 2, an outer water inlet of the pipe group buried pipe heat exchanger model is communicated with a water outlet of the circulating water mechanism 4, an inner water outlet of the pipe group buried pipe heat exchanger model is communicated with a water inlet of the circulating water mechanism 4, and the data acquisition mechanism is used for acquiring data.
Referring to fig. 1, the test sand box 2 comprises a sand box body 2-1 with an opening at the upper end and a test stratum 2-2; the test stratum 2-2 is arranged in the sand box body 2-1, the upper surface of the test stratum 2-2 is in contact heat exchange with the external environment, the test sand box 2 is arranged on the upper surface of the ground temperature control box 3, and the lower surface of the test sand box 2 is in contact heat exchange with the upper surface of the ground temperature control box 3, so that the test stratum 2-2 is in a ground temperature gradient.
Furthermore, in order to ensure the uniformity of the temperature field inside the test sand box 2 and avoid experimental errors caused by different distances from the edge of the test sand box 2 to the tube group heat exchanger model, the sand box body 2-1 is preferably a cylindrical body.
Furthermore, because the depth of the buried pipe of the medium-deep layer interference-free heating system is large, the ground heat exchanger can penetrate through a plurality of layers of strata with different physical parameters, the test stratum 2-2 is composed of a plurality of layers of soils with different physical parameters distributed from top to bottom, and the thickness of each layer of soil is gradually increased from top to bottom so as to simulate the strata with different physical parameters.
Referring to fig. 1, the tube bundle heat exchanger model is longitudinally inserted into the middle position of the test stratum 2-2 in the test sand box 2 and penetrates through the multilayer soil in the test stratum 2-2, the bottom end of the tube bundle heat exchanger model is positioned in the soil at the lowest layer, and the top end of the tube bundle heat exchanger model extends out of the upper surface of the test stratum 2-2; the pipe group pipe burying heat exchanger model is composed of a plurality of buried pipes 1-1, and the buried pipes 1-1 can be vertically inserted into a test stratum 2-2 in different arrangement modes so as to optimize a pipe distribution mode of a pipe group through experiment exploration.
Furthermore, each buried pipe 1-1 comprises an outer layer cavity 1-1-1, an inner layer cavity 1-1-2, an outer water inlet 1-1-3 and an inner water outlet 1-1-4; the buried pipe 1-1 is a long closed cavity, a pipeline 1-1-5 with two open ends is coaxially inserted along the length direction of the buried pipe 1-1, the cavity of the buried pipe 1-1 is divided into two parts, the inner part of the pipeline 1-1-5 is used as an inner layer cavity 1-1-2, the outer part of the pipeline 1-1-5 is used as an outer layer cavity 1-1-1, and the outer layer cavity 1-1-1 is communicated with the inner layer cavity 1-1-2 through an opening at the bottom end of the pipeline 1-1-5; an opening at the top end of the pipeline 1-1-5 is used as an inner water outlet 1-1-4; the upper end of the buried pipe 1-1 is opened to be used as an external water inlet 1-1-3, and the external water inlet 1-1-3 is communicated with the outer layer cavity 1-1-1.
Referring to fig. 1, the circulating water mechanism 4 comprises a high-low temperature cold-hot integrated machine 4-1, a water pump 4-2, a water separator 4-3, a water collector 4-4, a water inlet pipe 4-5 and a water outlet pipe 4-6; the water inlet of the water outlet pipe 4-6 is connected with the water outlet of the high-low temperature cooling and heating integrated machine 4-1, the water outlet of the water outlet pipe 4-6 is respectively connected with the outer water inlets 1-1-3 of the buried pipes 1-1, the inner water outlets 1-1-4 of the buried pipes 1-1 are respectively connected with the water inlet of the water inlet pipe 4-5, and the water outlet of the water inlet pipe 4-5 is connected with the water inlet of the high-low temperature cooling and heating integrated machine 4-1; the water pump 4-2 and the water separator 4-3 are arranged on the water outlet pipe 4-6 along the water flow direction, and the water collector 4-4 is arranged on the water inlet pipe 4-5.
In the embodiment, the water distributor 4-3 uniformly distributes cold water provided by the high-low temperature cooling and heating all-in-one machine 4-1 into each buried pipe 1-1 of the pipe cluster buried pipe heat exchanger model, and exchanges heat with heat in the test sand box 2 through the plurality of buried pipes 1-1, water from the pipe cluster buried pipe heat exchanger model is hot water, and backwater of all the buried pipes 1-1 is collected through the water collector 4-4 and returns to the high-low temperature cooling and heating all-in-one machine 4-1; according to the water supply system, the water distributor 4-3 is used for distributing the water supply of the high-low temperature cold-hot all-in-one machine 4-1, and the water collector 4-4 is used for collecting the return water of the high-low temperature cold-hot all-in-one machine 4-1, so that the same circulation flow of each buried pipe 1-1 in the pipe group buried pipe heat exchanger model is ensured.
In this embodiment, the high-low temperature cooling and heating all-in-one machine 4-1 adjusts the return water temperature according to a set heat load. This application passes through high low temperature hot and cold water all-in-one 4-1 reduces and comes from the higher water of the endothermic temperature of tube bank borehole heat exchanger model in the sand box, and the heat load of simulation heat supply building can guarantee that the heat load is stable, has succinctly accurate, advantage that stability is high.
Referring to fig. 1, the ground temperature control box 3 simulates an underground constant temperature heat source, creates a suitable temperature gradient for the soil with different physical parameters and different thicknesses in the test sand box 2, and simulates the ground temperature gradient of an actual stratum. The ground temperature control box 3 comprises a ground temperature control box body 3-1, a constant temperature controller 3-2 and a plurality of electric heating tubes 3-3 which are uniformly distributed, wherein the electric heating tubes 3-3 are distributed in the ground temperature control box body 3-1, and the constant temperature controller 3-2 is arranged outside the ground temperature control box body 3-1 and is connected with the electric heating tubes 3-3 to control the heat productivity of the electric heating tubes 3-3 and ensure that the temperature of water in the ground temperature control box body 3-1 is constant all the time.
Further, the box body 3-1 of the ground temperature control box is a cylindrical box body and has the same outer diameter as the box body 2-1 of the sand box; carrying out heat preservation and insulation treatment on the outer wall of the sand box body 2-1, the outer wall and the bottom of the ground temperature control box body 3-1; the heat preservation and insulation layer can reduce the heat dissipation of the soil in the sand box body 2-1 and the hot water in the ground temperature control box body 3-1, and on the premise of ensuring that a uniform temperature field is provided for the sand box soil, the volume of the ground temperature control box is reduced, and the power consumption of a thermoelectric tube is reduced.
Referring to fig. 1, the data acquisition mechanism 5 comprises a plurality of thermocouples 5-1, a flowmeter 5-2, two thermometers 5-3, a memory, a display and a sensing wire; the thermocouple 5-1, the flowmeter 5-2, the thermometer 5-3, the thermostatic controller 3-2 and the high-low temperature cold-hot integrated machine 4-1 are respectively connected with a memory through sensing lines, and data are displayed by a display.
Further, the thermocouples 5-1 are longitudinally and uniformly distributed in the test stratum 2-2 of the test sand box 2, wherein a row of thermocouples 5-1 is arranged on the surface of the soil layer at the uppermost layer, a row of thermocouples 5-1 is arranged between two adjacent soil layers with different physical property parameters, and a row of thermocouples 5-1 is arranged at the bottom of the soil layer at the lowermost layer; thermocouples are uniformly arranged in the depth direction of the test sand box 2, and the temperature of the soil at different depths can be measured; the thermocouples 5-1 are densely distributed at positions close to the tube bank heat exchanger buried model in the radial direction and sparsely distributed at positions far away from the tube bank heat exchanger buried model; because the temperature change speed of the sand box soil close to the pipe group heat exchanger burying model is high, and the temperature change of the sand box soil far away from the pipe group heat exchanger burying model is small or is kept unchanged, the thermocouples 5-1 densely arranged close to the pipe group heat exchanger burying can measure more accurate soil temperature, and the thermocouples 5-1 sparsely arranged far away from the pipe group heat exchanger burying model can reduce unnecessary measuring points and reduce the calculation amount.
Furthermore, one thermometer 5-3 is installed on the water outlet pipe 4-6, and the flowmeter 5-2 and the other thermometer 5-3 are installed on the water inlet pipe 4-5 along the water flow direction, so as to measure the water inlet temperature, the water outlet temperature and the flow of the pipe group buried pipe heat exchanger model in real time.
In this embodiment, the real-time temperature, flow rate, ground temperature gradient, heat load and soil temperature can be obtained by the data acquisition mechanism 5, and are used for analyzing and calculating the soil heat affected radius and the heat exchange amount of the heat exchanger model, and displaying the influence effect of the heat exchanger model of each factor.
The application embodiment 1 provides a heat exchange experimental method of a middle-deep layer double-pipe heat exchanger, which comprises the following specific experimental steps:
step 7, setting a determined ground temperature gradient, starting the constant temperature controller 3-2 to control the heat productivity of the uniformly distributed electric heating pipes, heating water in the box body of the ground temperature control box, and providing a constant ground temperature gradient;
step 8, standing the experimental system, and observing the soil temperature through a display until the soil temperature presents a certain gradient and keeps stable;
step 9, setting a high-low temperature cold and hot water integrated machine 4-1 to simulate heat load, and determining circulation flow and operation time;
step 10, starting a water pump 4-2, carrying out a heat exchange experiment in a pipe group pipe arrangement mode, and storing the temperature, the flow speed, the flow, the ground temperature gradient, the heat load and the soil temperature in the whole operation time by a memory;
step 11, calculating the heat exchange quantity of a certain tube group buried tube heat exchanger model in the running time to obtain a soil heat affected radius diagram when the running is finished;
step 12, clearing the soil in the sand box body, determining the next pipe group pipe distribution mode, repeating the steps, and simultaneously ensuring that other conditions except the pipe group pipe distribution mode are kept unchanged;
and step 13, after the experiments of all the pipe group pipe distribution modes are completed, comparing the heat exchange quantity of the pipe group in the running time of different pipe group pipe distribution modes with the heat affected radius of the soil at the end of running, and analyzing to obtain the influence result of the pipe group pipe distribution modes on the heat exchange capacity of the pipe group.
Example 2: a single-tube heat exchanger model is adopted to test the heat exchange effect of a certain circulating medium in two flowing directions; this embodiment provides a deep double-pipe heat exchanger heat transfer experimental system in well for single tube heat exchanger, and this embodiment is different with embodiment 1: the single-pipe heat exchanger model is a buried pipe 1-1, and the buried pipe 1-1 is coaxially arranged in a test stratum 2-2 in a test sand box 2; the circulating water mechanism 4 comprises a high-low temperature cold-hot integrated machine 4-1, a water pump 4-2, a water inlet pipe 4-5 and a water outlet pipe 4-6; the water inlet of the water outlet pipe 4-6 is connected with the water outlet of the high and low temperature cooling and heating integrated machine 4-1, the water outlet of the water outlet pipe 4-6 is connected with the outer water inlet 1-1-3 of the buried pipe 1-1 (the outer water inlet 1-1-3 can also be used as an outer water outlet), the inner water outlet 1-1-4 of the buried pipe 1-1 (the inner water outlet 1-1-4 can also be used as an inner water inlet) is connected with the water inlet of the water inlet pipe 4-5, and the water outlet of the water inlet pipe 4-5 is connected with the water inlet of the high and low temperature cooling and heating integrated machine 4-1; the water pump 4-2 is arranged on the water outlet pipe 4-6.
The embodiment 2 of the application provides a heat exchange experimental method for a middle-deep layer double-pipe heat exchanger, which comprises the following specific experimental steps:
step 7, setting a determined ground temperature gradient, starting the constant temperature controller 3-2 to control the heat productivity of the uniformly distributed electric heating pipes, heating water in the box body of the ground temperature control box 3, and providing a constant ground temperature gradient;
step 8, standing the experimental system, and observing the soil temperature through a display until the soil temperature presents a certain gradient and keeps stable;
step 9, setting a high-low temperature cold and hot water integrated machine 4-1 to simulate heat load, and determining circulation flow and operation time;
step 10, starting a water pump 4-2, performing a single-pipe circulating medium flow direction heat exchange experiment, and storing the temperature, the flow speed, the flow, the ground temperature gradient, the heat load and the soil temperature in the whole operation time by a memory;
step 11, calculating the heat exchange quantity of the single-pipe buried pipe heat exchanger model in the running time, and obtaining a soil heat affected radius map when the running is finished;
and 12, connecting a water outlet pipe 4-6 of the circulating water mechanism 4 with an inner water inlet of the buried pipe 1-1, connecting an outer water outlet of the buried pipe 1-1 with a water inlet pipe 4-5 of the circulating water mechanism 4, starting a water pump 4-2 to fill the buried pipe 1-1 with a circulating medium, repeating the steps, and simultaneously ensuring that other conditions except the flowing direction of the circulating medium are kept unchanged.
And step 13, after the experiment of two flowing directions of a certain circulating medium is completed, comparing the heat exchange quantity of the two flowing directions of the certain medium at the running time with the soil heat affected radius at the end of running, and analyzing to obtain the influence result of the flowing directions of the circulating medium on the heat exchange capacity of the tube group.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that features described in different dependent claims and herein may be combined in ways different from those described in the original claims. It is also to be understood that features described in connection with individual embodiments may be used in other described embodiments.
Claims (10)
1. The utility model provides a deep layer double-pipe heat exchanger heat transfer experimental system which characterized in that: the system comprises a cold region building environment simulation cabin (6), a pipe laying heat exchanger model (1), a test sand box (2), a ground temperature control box (3), a circulating water mechanism (4) and a data acquisition mechanism (5); the pipe-embedded heat exchanger model (1), the test sand box (2), the ground temperature control box (3), the circulating water mechanism (4) and the data acquisition mechanism (5) are arranged in the cold region building environment simulation cabin (6); the test sand box (2) is arranged on the upper surface of the ground temperature control box (3), and the test sand box (2) comprises a sand box body (2-1) with an opening at the upper end and a test stratum (2-2) consisting of a plurality of layers of soils with different physical property parameters distributed from top to bottom; the test stratum (2-2) is positioned in the sand box body (2-1), the buried pipe heat exchanger model (1) is longitudinally inserted in the middle of the test stratum (2-2) and penetrates through the multilayer soil in the test stratum (2-2), the bottom end of the buried pipe heat exchanger model (1) is positioned in the soil at the lowest layer of the test stratum (2-2), and the top end of the buried pipe heat exchanger model (1) extends out of the upper surface of the test stratum (2-2); a water inlet of the buried pipe heat exchanger model (1) is communicated with a water outlet of the circulating water mechanism (4), and a water outlet of the buried pipe heat exchanger model (1) is communicated with a water inlet of the circulating water mechanism (4); the data acquisition mechanism (5) is used for acquiring data.
2. The heat exchange experimental system of the middle-deep casing heat exchanger according to claim 1, characterized in that: the ground temperature control box (3) comprises a ground temperature control box body (3-1), a constant temperature controller (3-2) and a plurality of uniformly distributed electric heating tubes (3-3), wherein the electric heating tubes (3-3) are distributed in the ground temperature control box body (3-1), and the constant temperature controller (3-2) is arranged outside the ground temperature control box body (3-1) and connected with the electric heating tubes (3-3) to control the heat productivity of the electric heating tubes (3-3).
3. The heat exchange experimental system of the middle-deep casing heat exchanger according to claim 2, characterized in that: the circulating water mechanism (4) comprises a high-low temperature cold-hot all-in-one machine (4-1), a water pump (4-2), a water inlet pipe (4-5) and a water outlet pipe (4-6); the water inlet of the water outlet pipe (4-6) is connected to the water outlet of the high-low temperature cold-hot all-in-one machine (4-1), the water outlet of the water outlet pipe (4-6) is connected to the water inlet of the buried pipe heat exchanger model (1), the water outlet of the buried pipe heat exchanger model (1) is connected to the water inlet of the water inlet pipe (4-5), the water outlet of the water inlet pipe (4-5) is connected to the water inlet of the high-low temperature cold-hot all-in-one machine (4-1), and the water pump (4-2) is installed on the water outlet pipe (4-6).
4. The heat exchange experimental system of the middle-deep casing heat exchanger according to claim 3, characterized in that: the data acquisition mechanism (5) comprises a plurality of thermocouples (5-1), a flowmeter (5-2), two thermometers (5-3), a memory, a display and a sensing wire; the thermocouples (5-1) are longitudinally and uniformly distributed in a test stratum (2-2) of the test sand box (2), wherein a row of thermocouples (5-1) is arranged on the surface of the soil layer on the uppermost layer, a row of thermocouples (5-1) is arranged between two adjacent soil layers with different physical property parameters, and a row of thermocouples (5-1) is arranged at the bottom of the soil layer on the lowermost layer; the thermocouples (5-1) are densely distributed at positions close to the heat exchanger model (1) of the buried pipe in the radial direction and are sparsely distributed at positions far away from the heat exchanger model (1) of the buried pipe; one thermometer (5-3) is arranged on the water outlet pipe (4-6), and the flowmeter (5-2) and the other thermometer (5-3) are arranged on the water inlet pipe (4-5) along the water flow direction; the thermocouple (5-1), the flowmeter (5-2), the thermometer (5-3), the constant temperature controller (3-2) and the high-low temperature cold-hot integrated machine (4-1) are respectively connected with the memory through sensing lines, and data are displayed by the display.
5. The heat exchange experiment system of the medium-deep-layer double-pipe heat exchanger according to claim 4, characterized in that: the heat exchanger model (1) is a single-pipe heat exchanger model and is a buried pipe (1-1), the water outlet of the water outlet pipe (4-6) in the circulating water mechanism (4) is connected with the water inlet of the buried pipe (1-1), and the water outlet of the buried pipe (1-1) is connected with the water inlet of the water inlet pipe (4-5).
6. The heat exchange experimental system of the middle-deep casing heat exchanger according to claim 4, characterized in that: the buried pipe heat exchanger model (1) is a pipe group buried pipe heat exchanger model and consists of a plurality of buried pipes (1-1); the water outlets of water outlet pipes (4-6) in the circulating water mechanism (4) are respectively connected with the water inlets of the buried pipes (1-1), and the water outlets of the buried pipes (1-1) are respectively connected with the water inlets of the water inlet pipes (4-5); the circulating water mechanism (4) also comprises a water separator (4-3) and a water collector (4-4); the water separator (4-3) is arranged on the water outlet pipe (4-6) and is positioned behind the water pump (4-2), and the water collector (4-4) is arranged on the water inlet pipe (4-5).
7. The heat exchange experiment system of the middle-deep casing heat exchanger according to claim 5 or 6, characterized in that: each buried pipe (1-1) comprises an outer layer cavity (1-1-1), an inner layer cavity (1-1-2), an outer water inlet (1-1-3) and an inner water outlet (1-1-4); the inner layer cavity (1-1-2) is positioned in the outer layer cavity (1-1-1) and communicated with the outer layer cavity; the outer water inlet (1-1-3) is positioned at the upper end of the buried pipe (1-1) and communicated with the outer layer cavity (1-1-1), and the inner water outlet (1-1-4) is positioned at the top end of the buried pipe (1-1) and communicated with the inner layer cavity (1-1-2).
8. The method for carrying out the experiment by using the heat exchange experiment system of the middle-deep-layer double-pipe heat exchanger, which is disclosed by claim 7, is characterized in that: the specific experimental steps are as follows:
step 1, determining the type of a heat exchanger model of a buried pipe;
step 2, determining and fixing the position of the buried pipe (1-1), and determining and fixing the position of the thermocouple (5-1);
step 3, filling different soils with known physical parameters in a sand box body (2-1) in a layered manner to form a test stratum (2-2);
step 4, respectively connecting a water outlet pipe (4-6) of the circulating water mechanism (4) with a water inlet of the buried pipe (1-1), connecting a water outlet of the buried pipe (1-1) with a water inlet pipe (4-5) of the circulating water mechanism (4), and starting a water pump (4-2) to fill the buried pipe (1-1) with a circulating medium;
step 5, connecting the thermocouple (5-1), the flowmeter (5-2), the thermometer (5-3), the constant temperature controller (3-2) and the high-low temperature cold-hot integrated machine (4-1) with a memory through a sensing line;
step 6, standing the experimental system, and observing the soil temperature and the circulating water temperature through a display until the soil temperature and the circulating water temperature are the same as the environmental temperature;
step 7, setting a determined ground temperature gradient, starting a constant temperature controller (3-2) to control the heat productivity of the uniformly distributed electric heating pipes, heating water in a box body of a ground temperature control box, and providing a constant ground temperature gradient;
step 8, standing the experimental system, and observing the soil temperature through a display until the soil temperature presents a certain gradient and keeps stable;
step 9, setting a high-low temperature cold and hot water integrated machine (4-1) to simulate heat load, and determining circulation flow and operation time;
step 10, starting a water pump (4-2) to perform a heat exchange experiment, and storing the temperature, the flow speed, the flow, the ground temperature gradient, the heat load and the soil temperature in the whole operation time by a memory;
and 11, calculating the heat exchange quantity of the heat exchanger model of the buried pipe in the running time, and obtaining a soil heat affected radius diagram when the running is finished.
9. The method for heat exchange experiment of the medium-deep casing heat exchanger according to claim 8, characterized in that: in the step 1, a pipe group buried pipe heat exchanger model is adopted, and a pipe arrangement mode of a plurality of buried pipes (1-1) is designed; after the step 11 is finished, clearing the soil in the box body of the sand box, determining the next pipe group pipe distribution mode, repeating the steps 1 to 11, and simultaneously ensuring that other conditions except the pipe group pipe distribution mode are kept unchanged; after the experiment of all the pipe group pipe distribution modes is completed, the heat exchange quantity of the pipe group in the running time of different pipe group pipe distribution modes and the soil heat affected radius at the end of running are compared, and the influence result of the pipe group pipe distribution modes on the heat exchange capacity of the pipe group is analyzed.
10. The method for heat exchange experiment of the medium-deep casing heat exchanger according to claim 8, characterized in that: the step 1 is a single-pipe heat exchanger model; after the step 11 is finished, connecting a water outlet pipe (4-6) of the circulating water mechanism (4) with an inner water inlet of the buried pipe (1-1), connecting an outer water outlet of the buried pipe (1-1) with a water inlet pipe (4-5) of the circulating water mechanism (4), starting a water pump (4-2) to fill the buried pipe (1-1) with a circulating medium, repeating the step 5 to the step 11, and simultaneously ensuring that other conditions except the flowing direction of the circulating medium are kept unchanged; after the experiment of two flowing directions of a certain circulating medium is completed, the heat exchange quantity of the two flowing directions of the certain medium in the running time and the soil heat affected radius at the end of running are compared, and the influence result of the flowing direction of the circulating medium on the heat exchange capacity of the tube group is analyzed.
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| CN116559229B (en) * | 2023-05-08 | 2023-11-03 | 河北工程大学 | Sand box experiment system and method based on middle-deep buried pipe heat exchanger |
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