CN202649147U - Device for testing field thermal response of underground geotechnical layered thermal properties - Google Patents

Abstract

The utility model relates to a device for testing field thermal response of underground geotechnical layered thermal properties. According to the structure of the device, an outlet of an insulated water tank is connected with an inlet of a water pump, an inlet of the insulated water tank is connected with an outlet of an electromagnetic flow meter, an outlet of the water pump is connected with an inlet of a U-shaped pipe, an inlet of the electromagnetic flow meter is connected with an outlet of the U-shaped pipe through a flow regulating valve, an adjustable electric heater is arranged in the insulated water tank, and the adjustable electric heater, the electromagnetic flow meter and an optical fiber temperature sensor are connected with a data acquisition device through signal transmission lines. The defects of the conventional method that the distribution of geotechnical thermal properties in places of different depths cannot be obtained, the testing accuracy cannot be improved and the optimized design of underground buried pipes cannot be improved can be overcome. The values of underground geotechnical thermal properties in places of different depths, the geotechnical type of soil, the groundwater content and the seepage can be obtained, and the device has the advantages of high sensitivity, strong interference resistance, corrosion resistance, small installation size, no power requirements and low testing cost.

Description

The on-the-spot thermal response proving installation of the hot physical property of a kind of underground ground layering

Technical field

The utility model belongs to geothermal heat pump air-conditioner and utilizes technical field, is specifically related to a kind of on-the-spot thermal response proving installation of the hot physical property of a kind of underground ground layering of measuring underground different depth place ground thermal property parameter.

Background technology

Before the present utility model, the on-the-spot thermal response proving installation of existing underground ground thermal property is normally under permanent heat flux, measure instrument connection pipe laying circulation fluid out temperature, flow and heating power, by certain heat transfer model test data is carried out inverting and obtain the on-the-spot average ground thermal property value of pipe laying.And practical situation is, because underground buried tube is buried underground darker, the ground type distributes normally uneven in this depth range, and different depth place soil moisture content and seepage action of ground water speed are also different, cause its hot physical property to change greatly along depth direction, this is to determining that accurately pipe laying depth has a significant impact.Therefore, the ground thermal property that present proving installation can't obtain the different depth place distributes, and also just can't accomplish to improve measuring accuracy, improve the underground buried tube Optimization Design.

Summary of the invention

The purpose of this utility model just is to overcome defects, develops the on-the-spot thermal response proving installation of the hot physical property of a kind of underground ground layering.

The technical solution of the utility model is:

The on-the-spot thermal response proving installation of the hot physical property of a kind of underground ground layering, its technical characteristics is that the outlet of attemperater is connected with the import of water pump, the import of attemperater is connected with the outlet of electromagnetic flowmeter, the outlet of water pump is connected with the import of U-shaped pipe, the import of electromagnetic flowmeter is connected with the outlet of U-shaped pipe by flow control valve, be provided with the adjustable electric well heater in the attemperater, and adjustable electric well heater, electromagnetic flowmeter, fibre optic temperature sensor are connected with data collector by signal transmssion line.

The utility model is to descending traditionally device for testing rock-soil thermophysical properties to innovate, circulating fluid temperature when employing inserts in fibre optic temperature sensor in U-shaped pipe two arms and records the soil initial temperature at different depth place and operation, utilize line heat source fitting process and parameter optimization technology to derive the ground thermal property value at different depth place, its beneficial effect is:

(1) can obtain the underground ground thermal property value at different depth place, for the optimal design of earth source heat pump underground penstock heat interchanger provides more accurate data;

(2) can obtain soil initial temperature value and soilstone great soil group type, underground water content and the seepage flow situation at different depth place, for the optimization of drilling depth provides reliable basis;

(3) fibre optic temperature sensor has highly sensitive, strong interference immunity, corrosion-resistant, the advantages such as installation dimension is little, non-transformer requirement, and the probe temperature precision is higher under complex geological condition;

(4) be completed after, the fibre optic temperature sensor that inserts in U-shaped pipe two arms can recycling, has saved testing cost.

Other concrete advantage of the present utility model and effect will go on to say below.

Description of drawings

Fig. 1---the utility model test principle synoptic diagram.

Fig. 2---k layer soil fibre optic thermometer layered arrangement full-page proof synoptic diagram in the utility model test.

Each label represents among the figure:

Attemperater 1, adjustable electric well heater 2, water pump 3, electromagnetic flowmeter 4, flow control valve 5, fibre optic temperature sensor 6, data collector 7, U-shaped pipe 8, instrument connection 9.

Embodiment

Technical thought of the present utility model is exactly can only test the mean value that obtains ground thermal property in the depth range and the hot physics value of layering that can't obtain each depth for present underground ground thermal response proving installation, and a kind of on-the-spot thermal response proving installation of the hot physical property of underground ground layering that can measure simultaneously the underground ground thermal property value of different depth layer in the drilling depth scope is provided.

Test system structure described in the utility model comprises attemperater 1, adjustable electric well heater 2, water pump 3, electromagnetic flowmeter 4, flow control valve 5, fibre optic temperature sensor 6 and data collector 7, adjustable electric well heater 2 is installed in the attemperater 1, and wherein adjustable electric well heater 2, electromagnetic flowmeter 4 and fibre optic temperature sensor 6 are connected with data collector 7 by signal transmssion line; The outlet of attemperater 1 is connected with the import of water pump 3, the outlet of water pump 3 is connected with the import of U-shaped pipe 8, the outlet of U-shaped pipe 8 is connected with the import of electromagnetic flowmeter 4 by flow control valve 5, and the outlet of electromagnetic flowmeter 4 is connected with the import of attemperater 1, and U-shaped pipe 8 is plugged in the instrument connection 9; Data collector 7 comprises data acquisition module, data analysis module and control module; Adjustable electric well heater 2 is comprised of a plurality of electric heaters with different capacity, and its watt level is selected according to drilling depth; Connecting tube between each parts is surrounded by the insulating rubber plastic that thickness is 20mm outward.

The utility model application process brief description:

(1) on-the-spot at pipe laying, according to actual design situation drilling testing hole, choose and insert U-shaped pipe, and choose backfilling material by designing requirement and carry out backfill;

(2) as shown in Figure 2, underground soil is carried out the depth direction layering, and fibre optic temperature sensor 6 is inserted in two arms of U-shaped pipe, every layer of U-shaped water inlet tube arranged 3 measuring points at least with exit branch, to measure different depth layer soil initial temperature and fluid medial temperature when moving;

(3) connect U-shaped pipe and proving installation circulating water pipeline import and export on the ground, and carry out the work of open piping insulated heat with thermal insulation material;

(4) leave standstill at least 48 hours after, measure coolant-temperature gage in U-shaped pipe two arm of different depth layer, to obtain the initial temperature of each layer soil;

(5) opening electric heater and water circulating pump, and keep heater power constant, simultaneously with the different measurement data constantly of certain hour interval record: water temperature, circulating water flow, well heater heating power in U-shaped pipe two arm of different depth layer, test after about 48 hours and stop;

(6) utilize following method that test data is processed coefficient of heat conductivity, specific heat per unit volume and the boring thermal resistance value that obtains each layer soil, be specially:

Theoretical according to line heat source, every layer of soil is had:

T _f，k＝m _klnτ+b _k (1)

m _k＝Q _k/(4πλ _kL _k) (2)

$b_k=\frac{{\mathrm{<figure-callout\; id="4"\; label="Q\; k"\; filenames="HSA00000738438500011.png"\; state="\{\{state\}\}">Q</figure-callout>}}_k}{{4\mathrm{\&pi;\&lambda;}}_k{L}_k}[\ln \left(\frac{{4\mathrm{\&lambda;}}_k}{{\left(\mathrm{\&rho;c}\right)}_k}\right)-0.5772]+\frac{Q_k}{L_k}{R}_{b,k}+T_{\mathrm{ff},k}---\left(3\right)$

$Q_k=c\stackrel{.}{m}[(T_{\mathrm{fi},k}-T_{\mathrm{fo},k})-(T_{\mathrm{fi},k+1}-T_{\mathrm{fo},k+1})]---\left(4\right)$

In the formula, subscript k represents the soil number of plies, Q _kBe the heat exchange amount of k layer soil, W; L _kBe the degree of depth of k layer soil, m; λ _kBe the coefficient of heat conductivity of k layer soil, W/ (mK); (ρ c) _kBe the specific heat per unit volume of k layer soil, J/ (m ²K); R _{B, k}Be k layer unit length boring thermal resistance, (mK)/W; T _{F, k}Be k layer fluid medial temperature, ℃; T _{Fi, k}, T _{Fi, k+1}Be respectively the import and export temperature of the U-shaped water inlet pipe of k layer, ℃; T _{Fo, k+1}, T _{Fo, k}Be respectively the import and export temperature of the U-shaped exit branch of k layer, ℃; T _{Ff, k}Be the initial temperature of k layer soil, ℃; C is fluid mass specific heat, kJ/ (kg ℃); Be circulating fluid mass rate, kg/s;

Test by experiment the Q that obtains _kAnd different constantly each layer pipe laying fluid medial temperature T _{F, k}Value simulates formula (1) at temperature-time logarithmic coordinate axle and can obtain m _kThereby, obtain the coefficient of heat conductivity λ of each depth layer soil according to equation (2) _kAgain with λ _kValue substitution formula (1) is with (ρ c) _kWith R _{B, k}Be optimized variable, as majorized function, utilize Parameter Estimation Method can draw the specific heat per unit volume and boring thermal resistance value of each layer soil with formula (5);

$F=\underset{i=1}{\overset{N}{\mathrm{\&Sigma;}}}\underset{k=1}{\overset{n}{\mathrm{\&Sigma;}}}{(T_{{(f,k)}_{\mathrm{cal}}}-T_{(f,k)\exp })}^2---\left(5\right)$

In the formula, T _{(f, k) cal}Be the k layer soil fluid medial temperature that calculates, T _{(f, k) exp}Be the average water temperature of k layer soil that test obtains, n is the total number of plies of soil, and N is the data acquisition number of times.

The utility model is divided into some layers with the soil in the drilling depth scope, by arrange some fiber optic temperature measuring points in U-shaped pipe two arms of each depth layer, under permanent heating power condition, measures temperature value, flow and the heating power of fluid in each depth layer.Based on test data, adopt line source model that data are processed to each layer soil, utilize line heat source fitting process and incorporating parametric optimisation technique, thereby obtain coefficient of heat conductivity, specific heat per unit volume and the boring thermal resistance value of the underground ground in different depth place.

Claims (5)

1. the on-the-spot thermal response proving installation of the hot physical property of a underground ground layering, the outlet that it is characterized in that attemperater is connected with the import of water pump, the import of attemperater is connected with the outlet of electromagnetic flowmeter, the outlet of water pump is connected with the import of U-shaped pipe, the import of electromagnetic flowmeter is connected with the outlet of U-shaped pipe by flow control valve, be provided with the adjustable electric well heater in the attemperater, and adjustable electric well heater, electromagnetic flowmeter, fibre optic temperature sensor are connected with data collector by signal transmssion line.

2. the on-the-spot thermal response proving installation of the hot physical property of a kind of underground ground layering according to claim 1, it is characterized in that described fibre optic temperature sensor is to be arranged in U-shaped pipe two arms according to underground layering situation, and arrange at least three temperature points in U-shaped pipe two arms of every layer of soil.

3. the on-the-spot thermal response proving installation of the hot physical property of a kind of underground ground layering according to claim 1 is characterized in that described data collector comprises data acquisition module, data analysis module and control module.

4. the on-the-spot thermal response proving installation of the hot physical property of a kind of underground ground layering according to claim 1 is characterized in that described adjustable electric well heater is comprised of a plurality of electric heaters with different capacity, and its watt level is selected according to drilling depth.

5. the on-the-spot thermal response proving installation of the hot physical property of a kind of underground ground layering according to claim 1 is characterized in that the connecting tube between described parts is surrounded by the insulating rubber plastic that thickness is 20mm outward.

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