CN113358690A - Heat leakage experiment system and method for heat insulation layer loss of overhead steam pipeline - Google Patents
Heat leakage experiment system and method for heat insulation layer loss of overhead steam pipeline Download PDFInfo
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- CN113358690A CN113358690A CN202110055512.8A CN202110055512A CN113358690A CN 113358690 A CN113358690 A CN 113358690A CN 202110055512 A CN202110055512 A CN 202110055512A CN 113358690 A CN113358690 A CN 113358690A
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Abstract
The invention provides an overhead steam pipeline heat-insulating layer missing heat leakage experiment system which comprises a steam generation unit, a pipeline experiment unit, a heat exchange unit and a hydrophobic storage unit which are sequentially communicated. The invention also provides an experimental method based on the system. The invention has the advantages that: the steam generating unit is used for providing steam for the experiment system, high-temperature steam is processed based on the heat exchange unit, steam condensate water in the system is collected through the hydrophobic storage unit, the hydrophobic amount of the calculation system is conveniently collected, calculation is conveniently collected, the relation between the loss of the insulating layer and heat leakage loss in the low-pressure steam pipeline and the water attack risk of the system during operation of the pipeline can be researched under different operation pressures, therefore, experiment support and theoretical basis are provided for judging the operation condition of the thermal steam pipeline and establishing an algorithm model of the water attack risk of the steam pipeline, and a guidance method is provided for preliminarily determining the falling condition of the insulating layer through the change of the hydrophobic amount during the actual operation of the thermal steam pipeline.
Description
Technical Field
The invention relates to the technical field of steam pipeline heat-insulating layers, in particular to an experimental system and an experimental method for heat leakage loss of an overhead steam pipeline heat-insulating layer.
Background
The steam pipeline system is an important component of the urban heat supply system in China and belongs to the construction system of urban pipe network infrastructure. Along with the improvement of the living standard of residents, the heat supply area of China is increased year by year, the heat loss problem of the heat supply pipe network caused by pipe network blockage and leakage, heat preservation system failure and pipeline overheating is more and more obvious, the great energy waste is caused, and the sustainable development concept of the energy in the world is contrary to the sustainable development concept of the energy in the world. The aging and falling of the heat insulation layer are one of the main reasons for the failure of the heat insulation system of the heat supply pipeline, which can obviously affect the heating quality of residents and cause unnecessary heat energy loss. At present, a study on a steam pipeline insulating layer missing experiment system is lacked, and Guosui is a thesis; research on influence factors of thermal insulation effect of a thermal pipeline [ D ]; northeast university of petroleum; 2012's research relates to the influence of insulation construction damage to thermal power insulating tube, and this thesis adopts theoretical analysis, numerical simulation and field experiment's method, has demonstrated that local structural damage even of heat preservation can also produce very big adverse effect to the heat preservation effect, has researched the relation between heat preservation local structural damage degree of depth and heat preservation surface temperature, has provided the thinking of judging the heat preservation structure damage condition through the heat pipe insulation layer surface temperature variation. The paper sets a condition of constant operating pressure when researching the influence of the local structural damage of the heat-insulating layer on the heat-insulating effect of the thermal power pipeline, but the heat loss corresponding to the falling-off of the heat-insulating layer under different operating pressures of the thermal power pipeline is different; the thesis researches the relation between the damage depth of the pipeline heat-insulating layer and the surface temperature and heat loss of the pipeline, namely the damage condition of the heat-insulating layer can be judged through the change of the surface temperature or heat flow of the heat distribution pipeline, but monitoring the change of the surface temperature or the heat flow of the pipeline needs to be additionally provided with monitoring equipment and a monitoring system, so that the cost is higher, and the judgment of the damage and the loss condition of the heat-insulating layer through the change of the hydrophobic amount of a heat distribution pipeline network is more visual and convenient; the field experiment is greatly influenced by the external environment, and is not beneficial to the adjustment of working conditions and repeated experiments.
Disclosure of Invention
The invention aims to provide an experimental system for researching the relationship between heat insulation layer loss and heat leakage loss, system water repellent amount and pipeline operation water attack risk, provides experimental support and theoretical basis for judging the operation condition of a thermal steam pipeline and establishing an algorithm model of the steam pipeline water attack risk, and provides a guidance method for preliminarily determining the falling condition of the heat insulation layer through the change of the water repellent amount in the actual operation of the thermal steam pipeline.
The invention solves the technical problems through the following technical scheme: an overhead steam pipeline heat preservation missing heat leakage experiment system comprises a steam generation unit and a pipeline experiment unit which are sequentially communicated, wherein the steam generation unit is communicated with a water source through a pipeline, the pipeline experiment unit comprises an experiment pipeline for steam circulation, an outer sliding type steel sleeve heat preservation layer and a detachable heat preservation layer are sequentially sleeved on the outer side of the experiment pipeline along the steam circulation direction, the rear end of the pipeline experiment unit is connected with a heat exchange unit and a hydrophobic storage unit in parallel, the heat exchange unit condenses steam of the pipeline experiment unit, the hydrophobic storage unit comprises a first hydrophobic component and a water tank which are connected in series, the first hydrophobic component comprises a first hydrophobic pipeline and a second hydrophobic pipeline which are connected in parallel, a first hydrophobic pipeline valve is arranged on the first hydrophobic pipeline, and a second hydrophobic pipeline valve and a hydrophobic valve are sequentially arranged on the second hydrophobic pipeline, the water tank is provided with a water outlet pipeline.
According to the invention, steam is provided for an experimental system through a steam generating unit, the loss condition of the insulating layer is simulated through a detachable insulating layer, high-temperature steam is processed based on a heat exchange unit, steam condensate water in the system is collected through a hydrophobic storage unit, the hydrophobic amount of the system is conveniently collected and calculated, and the relation between the loss of the insulating layer and heat leakage loss, the hydrophobic amount of the system and the water attack risk of pipeline operation in a low-pressure steam pipeline can be researched under different operation pressures, so that experimental support and theoretical basis are provided for judging the operation condition of the thermal steam pipeline and establishing an algorithm model of the water attack risk of the steam pipeline, and a guidance method is provided for preliminarily determining the falling condition of the insulating layer through the change of the hydrophobic amount in the actual operation of the thermal steam pipeline.
Preferably, the detachable heat-insulating layer comprises a plurality of heat-insulating sections spliced along the length direction, and the heat-insulating sections can be detached from the experimental pipeline independently.
Preferably, a first pipeline pressure transmitter and a first pipeline temperature sensor are sequentially arranged on the experimental pipeline corresponding to the middle position of the outer sliding steel sleeve heat-insulating layer; and a second pipeline pressure transmitter and a second pipeline temperature sensor are sequentially arranged on the experimental pipeline at the tail end of the detachable heat-insulating layer.
Preferably, the outer sliding type steel sleeve heat-insulating layer comprises a high-temperature glass wool, an aluminum foil double-layer reflecting layer and a spiral steel pipe which are sequentially arranged from inside to outside, and the spiral steel pipe is a double-sided submerged arc welding spiral steel pipe coated with polyurea coating.
Preferably, the heat preservation section includes two detachable half round sleeves, and two half round sleeves can amalgamation fixed connection, half round sleeve includes silicate heat preservation and various steel tile shell that set gradually from inside to outside, the silicate heat preservation is the multilayer silicate cotton that high temperature glue bonding formed.
Preferably, one side of each of the two semicircular sleeves is rotatably connected through a hinge, the other side of each of the two semicircular sleeves is axially provided with a plurality of hasp locks, and the lapped sides of the two semicircular sleeves are respectively provided with a color steel tile shell which extends and protrudes along an arc direction relative to the silicate heat-insulating layer and a silicate heat-insulating layer which extends and protrudes along an arc relative to the color steel tile shell;
one end of the color steel tile shell extends along the axial direction to form a matching section, the diameter of the color steel tile shell of the matching section is increased, and the heat preservation section is matched with the color steel tile shell in an inserting mode along the axial direction through the matching section.
Preferably, the steam generating unit comprises a steam generator, a water inlet pipe and a steam output pipe, wherein a water inlet electromagnetic valve, a water inlet pressure transmitter and a water inlet flowmeter are sequentially arranged on the water inlet pipe along the water flow direction; and the steam output pipe is sequentially provided with an output regulating valve, an output pressure transmitter, an output temperature sensor and an output gas vortex shedding flowmeter.
Preferably, the heat exchange unit comprises a turbulent heat exchanger, a heat flow inlet of the turbulent heat exchanger is communicated with the pipeline experiment unit through a heat flow pipeline, a cold flow inlet of the turbulent heat exchanger is communicated with a water source through a cold flow pipeline, a heat flow outlet of the turbulent heat exchanger is connected with a second hydrophobic assembly through a first condensing pipeline, the second hydrophobic assembly has the same structure as the first hydrophobic assembly, and a cold flow outlet of the turbulent heat exchanger discharges condensed water through a second condensing pipeline;
the heat flow pipeline is sequentially provided with a heat flow regulating valve, a heat flow pressure transmitter and a heat flow temperature sensor; the cold flow pipeline is sequentially provided with a cold flow electromagnetic valve, a cold flow flowmeter, a cold flow pressure transmitter and a cold flow temperature sensor; and a condensation electromagnetic valve and a condensation temperature sensor are sequentially arranged on the second condensation pipeline.
Preferably, the hydrophobic storage unit is connected in parallel with the heat flow pipeline through a hydrophobic water inlet pipeline and is communicated with the pipeline experiment unit, a hydrophobic water inlet electromagnetic valve is arranged on the upper portion of the hydrophobic water inlet pipeline at the upper portion of the first hydrophobic component, a water tank temperature sensor is arranged on the pipeline between the water tank and the first hydrophobic component, a liquid level meter is arranged on the water tank, a steam outlet is formed in the upper portion of the water tank, a water tank electromagnetic valve is arranged on the water tank water outlet pipeline, and the water tank water outlet pipeline and the drainage of the heat exchange unit are discharged after confluence.
The invention also provides an experimental method for heat leakage of the heat-insulating layer of the overhead steam pipeline, which comprises the following steps
A: the detachable heat insulation layer of the experimental section is detached according to experimental requirements, and a plurality of surface temperature sensors are uniformly attached to the experimental section of the experimental pipeline along the circumferential direction;
b: the steam generation unit, the pipeline experiment unit, the heat exchange unit and the drainage storage unit are communicated, and a water inlet pipe of the steam generation unit and a cold flow pipeline of the heat exchange unit are in a closed state;
c: communicating the steam generation unit and the heat exchange unit with a water source, opening the steam generation unit, and closing first drain pipeline valves of the first drain assembly and the second drain assembly when the experiment system is full of steam;
d: regulating the steam supply and heat exchange unit of the steam generatorWhen the steam condensation amount and the steam pressure of the experimental pipeline corresponding to the outer sliding type steel sleeve heat-insulating layer are stabilized at a set value, recording the initial liquid level h of the water tank0Measuring the ambient temperature tfAnd the ambient wind speed w, closing the water outlet pipeline of the water tank; acquiring the steam pressure and temperature of the experimental pipeline corresponding to the middle position of the inner and outer sliding steel sleeve heat-insulating layer and the tail end position of the detachable heat-insulating layer in a monitoring time period and the liquid level height h of the water tank in a first period1Simultaneously acquiring temperature data of each surface temperature sensor in the monitoring time period according to a second cycle;
e: and opening a water outlet pipeline of the water tank, closing the steam generation unit, disconnecting the steam generation unit from a water source, and increasing the steam condensation amount of the heat exchange unit.
Preferably, the first and second liquid crystal materials are,
(1) the method for calculating the heat leakage loss amount comprises the following steps:
q＝α(tw-tf)
wherein q is the heat flux density of the outer surface of the experimental pipeline and the unit W/m2(ii) a Alpha is the total heat dissipation coefficient and the unit W/(m)2·K)；twThe average temperature of the outer wall surface of the pipeline is expressed in K;
in step A, four surface temperature sensors are arranged in the experimental section, then
Wherein, t1、t2、t3、t4The values of the four surface temperature sensors attached to the outer wall of the experimental section are respectively the average values; t is tfThe temperature is measured by a handheld infrared thermometer in a unit K; w is wind speed, unit m/s, measured by a handheld anemometer;
(2) the hydrophobic quantity calculation method comprises the following steps:
Q＝ρS(h1-h0)
wherein Q is the hydrophobic amount of the experimental system and is unit kg/h; rho is the density of water in kg/m3(ii) a S is the bottom area of the water tank, unit m2；h0The initial liquid level height h of the water tank when the steam pressure is stable1D, the height of the liquid level of the water tank in the experimental process of the step D is unit m;
(3) the calculation method of the water hammer risk coefficient comprises the following steps:
wherein n is the risk coefficient of pipeline water hammer, Q1Is the hydrophobic quantity, Q, of the experimental system when the heat-insulating layer is absent0The unit kg/h is the hydrophobic quantity of an experimental system under the state that the heat insulation layer is intact.
Preferably, the first period is 5min, the second period is 20min, and the monitoring time period is 1 hour.
Preferably, the experimental pipeline in the middle of the outer sliding steel sleeve heat-insulating layer is sequentially provided with a first pipeline pressure transmitter and a first pipeline temperature sensor; a second pipeline pressure transmitter and a second pipeline temperature sensor are sequentially arranged on the experimental pipeline at the tail end of the detachable heat-insulating layer;
the steam generating unit comprises a steam generator, a water inlet pipe and a steam output pipe, wherein a water inlet electromagnetic valve, a water inlet pressure transmitter and a water inlet flowmeter are sequentially arranged on the water inlet pipe along the water flow direction; the steam output pipe is sequentially provided with an output regulating valve, an output pressure transmitter, an output temperature sensor and an output gas vortex shedding flowmeter;
the heat exchange unit comprises a turbulent flow heat exchanger, a heat flow inlet of the turbulent flow heat exchanger is communicated with the pipeline experiment unit through a heat flow pipeline, a cold flow inlet of the turbulent flow heat exchanger is communicated with a water source through a cold flow pipeline, a heat flow outlet of the turbulent flow heat exchanger is communicated with the second drainage assembly through a first condensation pipeline, and a cold flow outlet of the turbulent flow heat exchanger discharges condensed water through a second condensation pipeline;
the heat flow pipeline is sequentially provided with a heat flow regulating valve, a heat flow pressure transmitter and a heat flow temperature sensor; the cold flow pipeline is sequentially provided with a cold flow electromagnetic valve, a cold flow flowmeter, a cold flow pressure transmitter and a cold flow temperature sensor; a condensation electromagnetic valve and a condensation temperature sensor are sequentially arranged on the second condensation pipeline;
the drainage storage unit is connected with the heat flow pipeline in parallel through a drainage water inlet pipeline and is communicated with the pipeline experiment unit, a drainage water inlet electromagnetic valve is arranged on the drainage water inlet pipeline at the upstream of the first drainage component, a water tank temperature sensor is arranged on a pipeline between the water tank and the first drainage component, a liquid level meter is arranged on the water tank, a steam outlet is arranged above the water tank, a water tank electromagnetic valve is arranged on a water tank water outlet pipeline, and the water tank water outlet pipeline is converged with the first condensation pipeline and the second condensation pipeline and then discharged;
in the step B, the water inlet electromagnetic valve and the cold flow electromagnetic valve are ensured to be in a closed state, and the condensation electromagnetic valve, the first drain pipeline valve and the second water pipeline valve of the first drain assembly and the second drain assembly, the drain water inlet electromagnetic valve and the water tank electromagnetic valve are in an open state; the opening degrees of the output regulating valve and the heat flow regulating valve are 100 percent;
in the step C, a cold flow electromagnetic valve is opened to enable a heat exchange unit to be communicated with a water source, a water inlet electromagnetic valve is opened to enable a steam generation unit to be communicated with the water source, and when the reading of a liquid level meter of the water tank is unchanged, steam is filled in the experiment system;
in the step D, the steam supply quantity of the steam generator is adjusted by adjusting the opening of the output adjusting valve, the steam condensation quantity of the heat exchange unit is adjusted by adjusting the opening of the heat flow adjusting valve, the opening of the output adjusting valve is positively correlated with the steam pressure in the pipeline, the opening of the heat flow adjusting valve is negatively correlated with the steam pressure in the pipeline, and the system is considered to be in a stable state when the value of the first pipeline pressure transmitter is stable and unchanged within 15 min.
Preferably, if a plurality of test pressures are involved in the test, after the step D, the water tank solenoid valve is opened, and when the values of the first pipeline pressure transmitter and the first pipeline temperature sensor of the pipeline test unit and the liquid level count value of the hydrophobic storage unit are stable, the step D is repeated.
Preferably, in the step E, after the experiment is completed, the electromagnetic valve of the water tank is opened, the steam generator is closed, the electromagnetic valve of the water inlet is closed, the opening degree of the heat flow regulating valve is increased, when the value of the output pressure transmitter is not less than 0.4MPa, the opening degree of the heat flow regulating valve is not more than 30%, when the value of the output pressure transmitter is not more than 0.15MPa, the first drain pipe valve of the second drain assembly is opened, the opening degree of the heat flow regulating valve is adjusted to 100%, and the cold flow electromagnetic valve is closed; and when the numerical value of the output pressure transmitter is less than or equal to 0.02MPa, opening a first drain pipeline valve of the first drain assembly.
The overhead steam pipeline heat-insulating layer missing heat leakage experimental system and the method provided by the invention have the advantages that: the steam generating unit is used for providing steam for the experimental system, the heat preservation layer missing condition is simulated through the detachable heat preservation layer, high-temperature steam is processed based on the heat exchange unit, steam condensate water in the system is collected through the hydrophobic storage unit, the system hydrophobic amount is conveniently collected and calculated, the relation between the heat preservation layer missing and heat leakage loss in the low-pressure steam pipeline and the relation between the system hydrophobic amount and pipeline operation water attack risk can be researched under different operation pressures, therefore, experimental support and theoretical basis are provided for judging the operation condition of the thermal steam pipeline and establishing an algorithm model of the steam pipeline water attack risk, and a guidance method is provided for preliminarily determining the heat preservation layer falling condition through the change of the hydrophobic amount in the actual operation of the thermal steam pipeline. Dismantlement formula heat preservation segmentation sets up, can study the influence of different positions heat preservation disappearance to the heat leakage condition according to the experiment needs, and the heat preservation section is fixed on the experiment pipeline through the hasp lock, makes things convenient for bare-handed dismouting, convenient to use.
Drawings
FIG. 1 is a schematic diagram of an experimental system for heat leakage of an overhead steam pipeline insulation layer in absence according to an embodiment of the present invention;
FIG. 2 is a block diagram of an experimental system for heat leakage due to lack of an insulating layer of an overhead steam pipeline according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a steam generation unit of an experimental system for heat leakage loss of an insulating layer of an overhead steam pipeline, provided by an embodiment of the invention;
FIG. 4 is a schematic diagram of a pipeline experiment unit of an experimental system for heat leakage due to lack of an insulating layer of an overhead steam pipeline, provided by an embodiment of the invention;
FIG. 5 is a schematic view of an outer sliding steel jacket insulating layer of an overhead steam pipeline insulating layer missing heat leakage experiment system provided by an embodiment of the invention;
FIG. 6 is a schematic view of a detachable insulating layer of an experimental system for heat leakage loss of an insulating layer of an overhead steam pipeline according to an embodiment of the present invention;
FIG. 7 is a schematic diagram of a thermal insulation section of an experimental system for lack of thermal insulation leakage of an overhead steam pipeline according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of a heat exchange unit of an experimental system for heat leakage loss of an insulating layer of an overhead steam pipeline, provided by an embodiment of the present invention;
fig. 9 is a schematic view of a hydrophobic storage unit of an experimental system for lack of heat leakage of an insulating layer of an overhead steam pipeline according to an embodiment of the present invention.
Detailed Description
To make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention are described below in detail and completely with reference to the accompanying drawings, and it is apparent that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1 and fig. 2, the embodiment provides an empty steam pipeline heat preservation disappearance heat leakage experimental system, which includes a steam generation unit 1 and a pipeline experimental unit 2 that are sequentially communicated, the steam generation unit 1 is communicated with a water source through a water inlet pipe 12, with reference to fig. 3, the pipeline experimental unit 2 includes an experimental pipeline 21 for steam circulation, an outer sliding steel jacket heat preservation layer 5 and a detachable heat preservation layer 6 are sleeved outside the experimental pipeline 21 along a steam circulation direction, a heat exchange unit 3 and a hydrophobic storage unit 4 are connected in parallel at the rear end of the pipeline experimental unit 2, the heat exchange unit 3 is cooled by heat exchange between tap water and steam, with reference to fig. 9, the hydrophobic storage unit 4 includes a first hydrophobic component 41 and a water tank 42 that are connected in series, the first hydrophobic component 41 includes a first hydrophobic pipeline 411 and a second hydrophobic pipeline 412 that are connected in parallel, the first drain pipe 411 is provided with a first drain pipe valve 413, the second drain pipe 412 is sequentially provided with a second drain pipe valve 414 and a drain valve 415, and the water tank 42 is provided with a water outlet pipe 47.
This embodiment provides steam through steam generation unit 1 to the experimental system, through the heat preservation disappearance condition of dismantlement formula heat preservation 6 simulation, high-temperature steam is handled based on heat exchange unit 3, steam condensate water in the collection system based on hydrophobic storage unit 4, can collect and monitor system's hydrophobic volume through water tank 42, conveniently collect the calculation, can be under different operating pressure, study heat preservation disappearance and heat leakage loss in the low pressure steam conduit, the relation between system hydrophobic volume and the pipeline operation water hammer risk, thereby for judging heating power steam conduit operation operating condition and establishing the algorithm model of steam conduit water hammer risk provide experimental support and theoretical foundation, provide a guidance method for tentatively confirming the heat preservation condition of droing through the change of hydrophobic volume in heating power steam conduit actual operation.
Referring to fig. 3, the steam generating unit 1 includes a steam generator 11, a water inlet pipe 12 and a steam output pipe 13, wherein a water inlet electromagnetic valve 121, a water inlet pressure transmitter 122 and a water inlet flow meter 123 are sequentially arranged on the water inlet pipe 12 along a water flow direction; the steam output pipe 13 is sequentially provided with an output regulating valve 131, an output pressure transmitter 132, an output temperature sensor 133 and an output gas vortex shedding flowmeter 134, the steam generator 11 adopts an electric heating steam generator, the water inlet pipe 12 is communicated with a tap water pipeline, and the water inlet pipe 12 and the steam output pipe 13 are seamless steel pipes with the diameter of phi 45x 3.5.
Referring to fig. 4, the experimental pipe 21 is a seamless steel pipe with a length of more than 30 m, i.e., phi 219x7, and the end of the steam output pipe 13 is communicated with the experimental pipe 21 through a first reducer union 135 (phi 45x3.5 is reduced to phi 219x 7); the outer sliding steel sleeve heat-insulating layer 5 has enough length to ensure stable and controllable operation of the experimental system, the length of the detachable heat-insulating layer 6 is determined according to experimental requirements, in a preferred embodiment, approximately the front 2/3 of the experimental pipeline 21 is provided with the outer sliding steel sleeve heat-insulating layer 5, and approximately the rear 1/3 of the experimental pipeline is provided with the detachable heat-insulating layer 6. A first pipeline pressure transmitter 22 and a first pipeline temperature sensor 23 are arranged on the experiment pipeline 21 corresponding to the approximate middle position of the outer sliding type steel sleeve heat-insulating layer 5, and a second pipeline pressure transmitter 24 and a second pipeline temperature sensor 25 are sequentially arranged on the experiment pipeline 21 corresponding to the tail end of the detachable heat-insulating layer 6.
Referring to fig. 5, the outer sliding steel jacket insulating layer 5 comprises a high-temperature glass wool 51, an aluminum foil double-layer reflecting layer 52 and a spiral steel pipe 53 which are sequentially arranged from inside to outside, and the spiral steel pipe 53 is a double-sided submerged arc welding spiral steel pipe coated with polyurea coating.
Referring to fig. 4 again, the detachable heat-insulating layer 6 includes a plurality of heat-insulating sections 61 spliced along the length direction, the heat-insulating sections 61 can be independently detached from the experimental pipeline 21, with reference to fig. 6 and 7, the heat-insulating sections 61 include two detachable semicircular sleeves 62, the two semicircular sleeves 62 can be spliced and fixed to form the heat-insulating section 61 sleeved on the experimental pipeline 21, each semicircular sleeve 62 includes a silicate heat-insulating layer 63 and a color steel tile shell 64 sequentially arranged from inside to outside, and the silicate heat-insulating layer 63 is a multilayer silicate cotton formed by high-temperature glue bonding; in the embodiment, one side of each of the two semicircular sleeves 62 is rotatably connected through a hinge 65, the axial direction of the hinge 65 is parallel to the axial direction of the experimental pipeline 21, and the other side of each of the two semicircular sleeves is axially provided with a plurality of snap locks 66 which are locked and fixed on the experimental pipeline 21 through the snap locks 66, so that the two semicircular sleeves can be conveniently disassembled and assembled by hands, and are convenient to use; the lap joint sides of the two semicircular sleeves 62 are respectively provided with a color steel tile shell 64 which extends and protrudes along the arc direction relative to the silicate heat-insulating layer 63, and a silicate heat-insulating layer 63 which extends and protrudes along the arc relative to the color steel tile shell 64; one end of the color steel tile shell 64 extends axially to form a matching section 67, the diameter of the color steel tile shell 64 of the matching section 67 is increased, and the heat preservation section 61 is in inserting fit with the matching section 67 axially; therefore, adjacent heat preservation sections 61 can be mutually inserted and occluded, the heat preservation effect of adjacent positions is ensured, and the interference to the experimental result is reduced; at least three snap locks 66 are provided on the heat retaining section 61 to lock the two ends and the middle position of the heat retaining section 61.
In the experiment, in order to prevent unnecessary heat loss, all other pipelines passing steam need to be added with heat preservation measures, such as wrapping heat preservation by using 10mm tin foil heat preservation cotton, except the experimental pipeline 21 wrapped by the outer sliding steel sleeve heat preservation layer 5 and the detachable heat preservation layer 6.
Referring to fig. 8, the heat exchange unit 3 comprises a turbulent heat exchanger 31, a hot fluid inlet of the turbulent heat exchanger 31 is communicated with the pipeline experiment unit 2 through a hot fluid pipeline 32, a cold fluid inlet is communicated with a water source through a cold fluid pipeline 33, a hot fluid outlet is communicated with a second water-repellent component 36 through a first condensing pipeline 34, the second water-repellent component 36 has the same structure as the first water-repellent component 41, and a cold fluid outlet discharges condensed water through a second condensing pipeline 35; the heat flow pipeline 32 is a phi 45x3.5 seamless steel pipe, the tail end of the experimental pipeline 21 is communicated with the heat flow pipeline 32 through a second reducing joint 26 (phi 219x7 is reduced to phi 45x3.5), and the heat flow pipeline 32 is sequentially provided with a heat flow regulating valve 321, a heat flow pressure transmitter 322 and a heat flow temperature sensor 323; the cold flow pipeline 33 is sequentially provided with a cold flow electromagnetic valve 331, a cold flow meter 332, a cold flow pressure transmitter 333 and a cold flow temperature sensor 334; a condensation solenoid valve 351 and a condensation temperature sensor 352 are sequentially arranged on the second condensation pipeline 35; the drainage of the second condensation pipeline 35 is merged with the drainage of the second drainage component 36 and is discharged.
With reference to fig. 9, the hydrophobic storage unit 4 is connected in parallel with the thermal flow pipe 32 through a hydrophobic inlet pipe 43 and is communicated with the pipe experiment unit 2, a hydrophobic inlet electromagnetic valve 44 is arranged on the hydrophobic inlet pipe 43 at the upstream of the first hydrophobic component 41, a water tank temperature sensor 45 is arranged on the pipe between the water tank 42 and the first hydrophobic component 41, a liquid level meter 46 is arranged on the water tank 42, a steam outlet (not shown) is arranged above the water tank 42, a water tank electromagnetic valve 471 is arranged on an outlet pipe 47 of the water tank 42, and with reference to fig. 2, the outlet pipe 47 and the drainage of the heat exchange unit 3 are converged and then discharged.
Further, for the convenience of controlling whole experimental system, experimental system still includes PLC remote control unit 7, and each solenoid valve, flowmeter, temperature sensor, pressure transmitter and steam generator 21, level gauge 46 in the experimental system all with PLC remote control unit 7 communication connection, can be by PLC remote control unit 7 change state to feed back PLC remote control unit 7 with self operating condition and monitoring numerical value, specific communication and control method are the ordinary technical means in this field, and this application is no longer repeated.
In order to facilitate individual maintenance of each component, in this embodiment, a manual gate valve is disposed on each of the water inlet electromagnetic valve 121, the output adjusting valve 131, the heat flow adjusting valve 321, the cold flow electromagnetic valve 331, the condensation electromagnetic valve 351, the first drain pipe valve 413 and the second water pipe valve 414 of the first drain assembly 41, the first drain pipe valve 363 and the second water pipe valve 364 of the second drain assembly 36, the upstream pipes of the drain water inlet electromagnetic valve 44 and the water tank electromagnetic valve 471, and a manual gate valve is disposed downstream of the drain valves 415 and 365 of the experimental system.
Based on the above experimental system, the embodiment further provides an experimental method for heat leakage of the insulating layer of the overhead steam pipeline, which comprises the steps of
A: the detachable heat-insulating layer 6 of the experimental section is detached according to experimental requirements, and 4 surface temperature sensors are uniformly attached to the experimental section of the experimental pipeline 21 along the circumferential direction;
b: the steam generation unit 1, the pipeline experiment unit 2, the heat exchange unit 3 and the hydrophobic storage unit 4 are ensured to be communicated, and the water inlet pipe 12 of the steam generation unit 1 and the cold flow pipeline 33 of the heat exchange unit 3 are in a closed state;
c: communicating the steam generation unit 1 and the heat exchange unit 3 with a water source, opening the steam generation unit 1, and closing the first drain pipeline valve 413 of the first drain assembly 41 and the first drain pipeline valve 363 of the second drain assembly 36 when the experiment system is filled with steam;
d: adjusting the steam supply amount of the steam generation unit 1 and the steam condensation amount of the heat exchange unit 3, and recording the initial liquid level h of the water tank 42 when the steam pressure of the experimental pipeline 21 corresponding to the outer sliding type steel sleeve heat-insulating layer 5 is stabilized at a set value0Measuring the ambient temperature tfAnd ambient windSpeed w, closing the outlet conduit 47 of the water tank 42; acquiring the steam pressure and the temperature of the experimental pipeline 21 corresponding to the middle position of the inner and outer sliding steel sleeve heat-insulating layer 5 and the tail end position of the detachable heat-insulating layer 6 in a monitoring time period and the liquid level height h of the water tank 42 in a first period1Simultaneously acquiring temperature data of the four surface temperature sensors in the monitoring time period according to a second period;
e: the water outlet pipe 47 of the water tank 42 is opened, the steam generator unit 1 is closed, the communication between the steam generator unit 1 and the water source is cut off, and the steam condensation amount of the heat exchange unit 3 is increased.
The calculation is carried out according to the results of the above experiment, and the specific calculation method is as follows:
(1) the method for calculating the heat leakage loss amount comprises the following steps:
q＝α(tw-tf)
wherein q is the outer surface heat flux density of the experimental section of the experimental pipeline 21 in W/m2(ii) a Alpha is the total heat dissipation coefficient and the unit W/(m)2·K)；twThe average temperature of the outer wall surface of the pipeline is expressed in K; t is t1、t2、t3、t4The values of the four surface temperature sensors attached to the outer wall of the experimental section are respectively the average values; t is tfThe temperature is measured by a handheld infrared thermometer in a unit K; w is wind speed, unit m/s, measured by a handheld anemometer;
(2) the hydrophobic quantity calculation method comprises the following steps:
Q＝ρS(h1-h0)
wherein Q is the hydrophobic amount of the experimental system and is unit kg/h; rho is the density of water in kg/m3(ii) a S is the bottom area of the water tank, unit m2Therefore, the application requires that the shape of the water tank 42 is uniform and is not uniform when usedWhen the water tank is homogenized, the volume of the stored water in the water tank can be directly obtained for calculation; h is0The initial liquid level height h of the water tank when the steam pressure is stable1D, the height of the liquid level of the water tank in the experimental process of the step D is unit m;
(3) the calculation method of the water hammer risk coefficient comprises the following steps:
wherein n is the risk coefficient of pipeline water hammer, Q1Is the hydrophobic quantity, Q, of the experimental system when the heat-insulating layer is absent0The hydrophobic quantity of the experimental system under the intact state of the heat preservation layer, unit kg/h, can be respectively tested under the condition of dismantling the detachable heat preservation layer 6 and under the condition of not dismantling the detachable heat preservation layer 6 to obtain the corresponding hydrophobic quantity.
In the experiment, the first period is set to be 5min, the second period is 20min, and the monitoring time period is 1 hour.
Based on the introduction of the specific composition of the experimental system, in step B, all the manual gate valves are ensured to be in an open state before the experiment begins, and the water inlet electromagnetic valve 121 and the cold flow electromagnetic valve 331 are ensured to be in a closed state; the condensation electromagnetic valve 351, the first drain pipe valve 413 and the second water pipe valve 414 of the first drain assembly 41, the first drain pipe valve 363 and the second water pipe valve 364 of the second drain assembly 36, the drain water inlet electromagnetic valve 44 and the water tank electromagnetic valve 471 are in an open state; the opening degrees of the output regulating valve 131 and the heat flow regulating valve 321 are set to 100%.
In the step C, the cold flow electromagnetic valve 331 is opened to connect the heat exchange unit 3 with a water source, the water inlet electromagnetic valve 121 is opened to connect the steam generation unit 1 with the water source, the pressure value of the water inlet pressure transmitter 122 is observed, if the pressure is greater than 0.1MPa, it is indicated that the water inlet pipe 12 is full of pressurized water, at this time, the steam generator 11 can be started, water is first injected into the steam generator 11, in this embodiment, a ball float valve is arranged in the steam generator 11, and water is automatically injected until the liquid level reaches 80cm when the water level is lower than 80 cm; when the water level reaches 80cm for the first time, a heating switch of a steam generator 11 is turned on for heating, the steam generator 11 is provided with at least two high and low heating gears, in order to quickly warm the pipe, the high gears are used for working when heating is started, condensed water generated by the warm pipe and a small amount of condensed water in the pipe and newly generated steam form gas-liquid two-phase flow, so that a water hammer phenomenon occurs in the pipe, sound can be heard in an experiment, when the water hammer sound is too large, the low gears can be selected for heating, and in the specific experiment, the gears are selected based on working experience; different gears only influence the preparation time and do not influence the experimental result.
In the experiment preparation stage, the numerical values of all instruments in the experiment system are observed, the pressure and temperature states of all the components are mastered, and the state of the whole experiment system is roughly judged; when the reading of the liquid level meter 46 is unchanged, the experiment can be started by considering that the experiment pipeline 21 is filled with steam; for the sake of safety, in the present embodiment, when the reading of the liquid level meter 46 is not changed, and at the same time, the steam discharge amount of the steam discharge port on the water tank 42 is stable and continuous, and there is no water hammer sound in the experimental system, it is considered that the condensed water is completely discharged, and the steam has filled the system, and the first drain pipe valve 413 of the first drain assembly 41 and the first drain pipe valve 361 of the second drain assembly 36 are closed, and the steam is prevented from entering the downstream pipe.
The steam generator 11 is opened in the initial stage of the experiment, steam generated by the steam generator 11 is heated, steam is easily condensed due to the factors such as lower temperature of a pipeline and residual condensed water in the pipeline, mainly condensed water and a small amount of steam in the pipeline, in order to discharge the pipeline condensed water quickly, the first drain pipeline valve 413 of the first drain assembly 41 and the first drain pipeline valve 363 of the second drain assembly 36 are in an open state, after the pipeline is filled with steam, if the first drain pipeline valves 413 and 363 are still in an open state, a large amount of steam can directly enter a downstream pipeline, the steam is in a stable leakage state, the steam pressure of the system is increased to meet the experiment condition, the experiment efficiency is reduced, in addition, a large amount of high-temperature steam enters an outdoor sewage pipeline for a long time, and the outdoor drainage system can be damaged. Therefore, the main function of first drain valves 413 and 363 is to help the system to drain the condensed water quickly in the experiment preparation stage, and to open when second drain valves 414 and 364 are out of service, so as to drain the condensed water out of the system, thereby providing emergency guarantee.
In step D, the steam supply amount of the steam generator 11 is adjusted by adjusting the opening degree of the output adjusting valve 131, the steam condensation amount of the heat exchanging unit 3 is adjusted by adjusting the opening degree of the heat flow adjusting valve 321, the opening degree of the output adjusting valve 131 is positively correlated with the steam pressure in the pipeline, the opening degree of the heat flow adjusting valve 321 is negatively correlated with the steam pressure in the pipeline, and the system is considered to be in a stable state if the value of the first pipeline pressure transmitter 22 is stable and unchanged within 15 min.
If the experiment under different steam pressures needs to be carried out, after the step D is completed, the water tank solenoid valve 471 is opened, and when the values of the first pipeline pressure transmitter 22 and the second pipeline temperature sensor 23 and the value of the liquid level meter 46 are kept stable within 15min, the step D is repeated, and the system pressure is adjusted to the set value.
In step E, after the experiment is completed, the water tank solenoid valve 471 is opened, the steam generator 11 is closed, the water inlet solenoid valve 121 is closed, the opening degree of the heat flow regulating valve 321 is increased, and when the value of the output pressure transmitter 132 is greater than or equal to 0.4MPa, the opening degree of the heat flow regulating valve 321 is less than or equal to 30% to prevent the experimental equipment from being damaged due to too fast pressure relief; when the value of the output pressure transmitter 132 is less than or equal to 0.15MPa, the first drain pipeline valve 363 of the second drain assembly 36 is opened, meanwhile, the opening degree of the heat flow regulating valve 321 is regulated to 100%, and the cold flow electromagnetic valve 331 is closed; when the value of the output pressure transmitter 132 is less than or equal to 0.02MPa, the first drain pipeline valve 413 of the first drain assembly 41 is opened, and the residual condensed water in the pipeline is drained into the outdoor sewage pipeline in an accelerated manner. After the experiment system cools off to the normal atmospheric temperature, can have in the steam generator not in time to heat into the running water of steam and a small amount of condensation waste water, for reducing steam generator's corrosion probability, the preferred blowoff valve that sets up in steam generator bottom opens the blowoff valve after the experiment is accomplished and discharges waste water, and steam generator's waste water can be through directly leading to outdoor sewer line in addition to hose, also can use the container to accept waste water.
When the value of the output pressure transmitter 132 is continuously decreased, which indicates that there is less steam in the system, and when there is enough steam in the system, only a small amount of steam flows to the subsequent non-experimental pipes through the first drain pipe valves 413 and 363, and there is substantially no water hammer with the condensed water in the downstream pipes, so that the first drain pipe valves 413 and 363 can be opened; the critical values corresponding to the pressure transmitter 132 and the heat flow adjusting valve 321 in step E are empirical values obtained through experiments, and as the steam pressure decreases, the first drain pipe valve 363 of the second drain assembly 36 can be opened first, because the second drain assembly 36 is connected behind the turbulent heat exchanger 31, although the cold flow solenoid valve 331 for controlling the entering of the tap water is closed, the steam has a larger contact area and longer time for exchanging heat and condensing with the outside due to the existence of the turbulent heat exchanger 31, and the upstream of the first hydrophobic component 41 is directly connected with the experimental pipeline 21, i.e., under equivalent pressure conditions, the amount of steam to first steam trap valve 413 of first steam trap assembly 41 is greater than first steam trap valve 313 of second steam trap assembly 36, therefore, less steam in the system is required to open first drain conduit valve 413 of first drain assembly 41.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (15)
1. The utility model provides an overhead steam pipeline heat preservation disappearance heat leak test system which characterized in that: including the steam generation unit and the pipeline experiment unit that communicate in proper order, the steam generation unit passes through the pipeline intercommunication with the water source, pipeline experiment unit is including the experiment pipeline that supplies the steam circulation, the outside of experiment pipeline is equipped with outer slidingtype steel bushing heat preservation and dismantlement formula heat preservation along steam circulation direction cover, pipeline experiment unit rear end parallel connection has heat transfer unit and hydrophobic storage unit, the steam of heat transfer unit condensation duct experiment unit, hydrophobic storage unit is including the first hydrophobic subassembly and the water tank of establishing ties, first hydrophobic subassembly is including parallelly connected first hydrophobic pipeline and second hydrophobic pipeline, be provided with first hydrophobic pipeline valve on the first hydrophobic pipeline, set gradually second hydrophobic pipeline valve and hydrophobic valve on the second hydrophobic pipeline, the water tank is provided with outlet conduit.
2. The experimental system for heat leakage of the insulating layer of the overhead steam pipeline in absence of the heat insulating layer according to claim 1, characterized in that: the detachable heat-insulating layer comprises a plurality of heat-insulating sections spliced along the length direction, and the heat-insulating sections can be detached from the experimental pipeline independently.
3. The experimental system for heat leakage of the insulating layer of the overhead steam pipeline in absence of the heat insulating layer according to claim 2, characterized in that: a first pipeline pressure transmitter and a first pipeline temperature sensor are sequentially arranged on the experimental pipeline corresponding to the middle position of the outer sliding steel sleeve heat-insulating layer; and a second pipeline pressure transmitter and a second pipeline temperature sensor are sequentially arranged on the experiment pipeline corresponding to the tail end of the detachable heat-insulating layer.
4. The experimental system for heat leakage of the insulating layer of the overhead steam pipeline in absence of the heat insulating layer according to claim 2, characterized in that: the outer sliding type steel sleeve heat insulation layer comprises high-temperature glass wool, an aluminum foil double-layer reflecting layer and a spiral steel pipe which are sequentially arranged from inside to outside, and the spiral steel pipe is a double-sided submerged arc welding spiral steel pipe coated with polyurea coating.
5. The experimental system for heat leakage of the insulating layer of the overhead steam pipeline in absence of the heat insulating layer according to claim 2, characterized in that: the heat preservation section includes two detachable semicircle sleeves, and two semicircle sleeves can amalgamation fixed connection, the semicircle sleeve includes silicate heat preservation and various steel tile shell that sets gradually from inside to outside, the silicate heat preservation is the multilayer silicate cotton that high temperature glue bonding formed.
6. The experimental system for heat leakage of the insulating layer of the overhead steam pipeline in absence of the heat insulating layer according to claim 5, characterized in that: one side of each of the two semicircular sleeves is rotatably connected through a hinge, the other side of each of the two semicircular sleeves is provided with a plurality of hasp locks along the axial direction, and the lapped sides of the two semicircular sleeves are respectively provided with a color steel tile shell which extends and protrudes along the arc direction relative to the silicate heat-insulating layer and a silicate heat-insulating layer which extends and protrudes along the arc direction relative to the color steel tile shell;
one end of the color steel tile shell extends along the axial direction to form a matching section, the diameter of the color steel tile shell of the matching section is increased, and the heat preservation section is matched with the color steel tile shell in an inserting mode along the axial direction through the matching section.
7. The experimental system for heat leakage of the insulating layer of the overhead steam pipeline in absence of the heat insulating layer according to claim 1, characterized in that: the steam generating unit comprises a steam generator, a water inlet pipe and a steam output pipe, wherein a water inlet electromagnetic valve, a water inlet pressure transmitter and a water inlet flowmeter are sequentially arranged on the water inlet pipe along the water flow direction; and the steam output pipe is sequentially provided with an output regulating valve, an output pressure transmitter, an output temperature sensor and an output gas vortex shedding flowmeter.
8. The experimental system for heat leakage of the insulating layer of the overhead steam pipeline in absence of the heat insulating layer according to claim 1, characterized in that: the heat exchange unit comprises a turbulent flow heat exchanger, a heat flow inlet of the turbulent flow heat exchanger is communicated with the pipeline experiment unit through a heat flow pipeline, a cold flow inlet of the turbulent flow heat exchanger is communicated with a water source through a cold flow pipeline, a heat flow outlet of the turbulent flow heat exchanger is connected with a second hydrophobic assembly through a first condensing pipeline, the second hydrophobic assembly has the same structure as the first hydrophobic assembly, and a cold flow outlet of the turbulent flow heat exchanger discharges condensed water through the second condensing pipeline;
the heat flow pipeline is sequentially provided with a heat flow regulating valve, a heat flow pressure transmitter and a heat flow temperature sensor; the cold flow pipeline is sequentially provided with a cold flow electromagnetic valve, a cold flow flowmeter, a cold flow pressure transmitter and a cold flow temperature sensor; and a condensation electromagnetic valve and a condensation temperature sensor are sequentially arranged on the second condensation pipeline.
9. The experimental system for the heat leakage of the insulating layer of the overhead steam pipeline in the absence of the insulating layer according to claim 8, wherein: the water draining storage unit is connected with the heat flow pipeline in parallel through a water draining water inlet pipeline and is communicated with the pipeline experiment unit, a water draining water inlet electromagnetic valve is arranged on the upper portion of the first water draining assembly on the water draining water inlet pipeline, a water tank temperature sensor is arranged on a pipeline between the water tank and the first water draining assembly, a liquid level meter is arranged on the water tank, a steam outlet is formed in the upper portion of the water tank, a water tank electromagnetic valve is arranged on a water tank water outlet pipeline, and the water tank water outlet pipeline and the drainage of the heat exchange unit are discharged after confluence.
10. A method for conducting an overhead steam pipeline insulation loss heat leakage test using the system of any one of claims 1 to 9, characterized in that: comprises that
A: the detachable heat insulation layer of the experimental section is detached according to experimental requirements, and a plurality of surface temperature sensors are uniformly attached to the experimental section of the experimental pipeline along the circumferential direction;
b: the steam generation unit, the pipeline experiment unit, the heat exchange unit and the drainage storage unit are communicated, and a water inlet pipe of the steam generation unit and a cold flow pipeline of the heat exchange unit are in a closed state;
c: communicating the steam generation unit and the heat exchange unit with a water source, opening the steam generation unit, and closing first drain pipeline valves of the first drain assembly and the second drain assembly when the experiment system is full of steam;
d: adjusting the steam supply quantity of the steam generator and the steam condensation quantity of the heat exchange unit, and recording the initial liquid level h of the water tank when the steam pressure of the experimental pipeline corresponding to the outer sliding type steel sleeve heat insulation layer is stabilized at a set value0Measuring the ambient temperature tfAnd the ambient wind speed w, closing the water outlet pipeline of the water tank; acquiring the steam pressure and temperature of the experimental pipeline corresponding to the middle position of the inner and outer sliding steel sleeve heat-insulating layer and the experimental pipeline corresponding to the tail end position of the detachable heat-insulating layer in a monitoring time period and the liquid level height h of the water tank in a first period1Simultaneously with a second cycleMonitoring temperature data of four surface temperature sensors in a time period;
e: the water outlet pipeline of the water tank is opened, the steam generating unit is closed, the communication between the steam generating unit and a water source is cut off, and the steam condensation amount of the heat exchange unit is increased.
11. The experimental method for the actual heat leakage of the insulating layer of the overhead steam pipeline as claimed in claim 10, wherein: (1) the method for calculating the heat leakage loss amount comprises the following steps:
q＝α(tw-tf)
wherein q is the heat flux density of the outer surface of the experimental section of the experimental pipeline in W/m2(ii) a Alpha is the total heat dissipation coefficient and the unit W/(m)2·K)；twThe average temperature of the outer wall surface of the pipeline is expressed in K;
in step A, four surface temperature sensors are arranged in the experimental section, then
Wherein, t1、t2、t3、t4The values of the four surface temperature sensors attached to the outer wall of the experimental section are respectively the average values; t is tfThe temperature is measured by a handheld infrared thermometer in a unit K; w is wind speed, unit m/s, measured by a handheld anemometer;
(2) the hydrophobic quantity calculation method comprises the following steps:
Q＝ρS(h1-h0)
wherein Q is the hydrophobic amount of the experimental system and is unit kg/h; rho is the density of water in kg/m3(ii) a S is the bottom area of the water tank, unit m2；h0The initial liquid level height h of the water tank when the steam pressure is stable1D, the height of the liquid level of the water tank in the experiment in the step D is unit m;
(3) the calculation method of the water hammer risk coefficient comprises the following steps:
wherein n is the risk coefficient of pipeline water hammer, Q1Is the hydrophobic quantity, Q, of the experimental system when the heat-insulating layer is absent0The unit kg/h is the hydrophobic quantity of an experimental system under the state that the heat insulation layer is intact.
12. The experimental method for lack of heat leakage of the insulating layer of the overhead steam pipeline as claimed in claim 10, wherein: the first period is 5min, the second period is 20min, and the monitoring time period is 1 hour.
13. The experimental method for lack of heat leakage of the insulating layer of the overhead steam pipeline as claimed in claim 10, wherein:
the experimental pipeline at the middle position of the outer sliding steel sleeve heat insulation layer is sequentially provided with a first pipeline pressure transmitter and a first pipeline temperature sensor; a second pipeline pressure transmitter and a second pipeline temperature sensor are sequentially arranged on the experimental pipeline at the tail end of the detachable heat-insulating layer;
the steam generating unit comprises a steam generator, a water inlet pipe and a steam output pipe, wherein a water inlet electromagnetic valve, a water inlet pressure transmitter and a water inlet flowmeter are sequentially arranged on the water inlet pipe along the water flow direction; the steam output pipe is sequentially provided with an output regulating valve, an output pressure transmitter, an output temperature sensor and an output gas vortex shedding flowmeter;
the heat exchange unit comprises a turbulent flow heat exchanger, a heat flow inlet of the turbulent flow heat exchanger is communicated with the pipeline experiment unit through a heat flow pipeline, a cold flow inlet of the turbulent flow heat exchanger is communicated with a water source through a cold flow pipeline, a heat flow outlet of the turbulent flow heat exchanger is communicated with the second drainage assembly through a first condensation pipeline, and a cold flow outlet of the turbulent flow heat exchanger discharges condensed water through a second condensation pipeline;
the heat flow pipeline is sequentially provided with a heat flow regulating valve, a heat flow pressure transmitter and a heat flow temperature sensor; the cold flow pipeline is sequentially provided with a cold flow electromagnetic valve, a cold flow flowmeter, a cold flow pressure transmitter and a cold flow temperature sensor; a condensation electromagnetic valve and a condensation temperature sensor are sequentially arranged on the second condensation pipeline;
the drainage storage unit is connected with the heat flow pipeline in parallel through a drainage water inlet pipeline and is communicated with the pipeline experiment unit, a drainage water inlet electromagnetic valve is arranged on the drainage water inlet pipeline at the upstream of the first drainage component, a water tank temperature sensor is arranged on a pipeline between the water tank and the first drainage component, a liquid level meter is arranged on the water tank, a steam outlet is arranged above the water tank, a water tank electromagnetic valve is arranged on a water tank water outlet pipeline, and the water tank water outlet pipeline is converged with the first condensation pipeline and the second condensation pipeline and then discharged;
in the step B, the water inlet electromagnetic valve and the cold flow electromagnetic valve are ensured to be in a closed state, and the condensation electromagnetic valve, the first drain pipeline valve and the second water pipeline valve of the first drain assembly and the second drain assembly, the drain water inlet electromagnetic valve and the water tank electromagnetic valve are in an open state; the opening degrees of the output regulating valve and the heat flow regulating valve are 100 percent;
in the step C, a cold flow electromagnetic valve is opened to enable a heat exchange unit to be communicated with a water source, a water inlet electromagnetic valve is opened to enable a steam generation unit to be communicated with the water source, and when the reading of a liquid level meter of the water tank is unchanged, steam is filled in the experiment system;
in the step D, the steam supply quantity of the steam generator is adjusted by adjusting the opening of the output adjusting valve, the steam condensation quantity of the heat exchange unit is adjusted by adjusting the opening of the heat flow adjusting valve, the opening of the output adjusting valve is positively correlated with the steam pressure in the pipeline, the opening of the heat flow adjusting valve is negatively correlated with the steam pressure in the pipeline, and the system is considered to be in a stable state when the value of the first pipeline pressure transmitter is stable and unchanged within 15 min.
14. The experimental method for lack of heat leakage of the insulating layer of the overhead steam pipeline as claimed in claim 13, wherein: and D, if various experiment pressures are involved in the experiment, opening a water tank electromagnetic valve after the step D, and repeating the step D when the numerical values of the first pipeline pressure transmitter and the first pipeline temperature sensor of the pipeline experiment unit and the liquid level meter are stable.
15. The experimental method for lack of heat leakage of the insulating layer of the overhead steam pipeline as claimed in claim 13, wherein: step E, after the experiment is finished, opening a water tank electromagnetic valve, closing a steam generator, closing a water inlet electromagnetic valve, increasing the opening degree of a heat flow adjusting valve, and when the numerical value of an output pressure transmitter is not less than 0.4MPa, the opening degree of the heat flow adjusting valve is not more than 30%, and when the numerical value of the output pressure transmitter is not more than 0.15MPa, opening a first drain pipeline valve of a second drain assembly, adjusting the opening degree of the heat flow adjusting valve to 100%, and closing a cold flow electromagnetic valve; and when the numerical value of the output pressure transmitter is less than or equal to 0.02MPa, opening a first drain pipeline valve of the first drain assembly.
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