CN107133468B - Online soft measurement method for air intake of cooling fan section of indirect air cooling tower - Google Patents
Online soft measurement method for air intake of cooling fan section of indirect air cooling tower Download PDFInfo
- Publication number
- CN107133468B CN107133468B CN201710298885.1A CN201710298885A CN107133468B CN 107133468 B CN107133468 B CN 107133468B CN 201710298885 A CN201710298885 A CN 201710298885A CN 107133468 B CN107133468 B CN 107133468B
- Authority
- CN
- China
- Prior art keywords
- air
- sector
- temperature
- heat exchange
- radiator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G16—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS
- G16Z—INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR SPECIFIC APPLICATION FIELDS, NOT OTHERWISE PROVIDED FOR
- G16Z99/00—Subject matter not provided for in other main groups of this subclass
Landscapes
- Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
- Medicines Containing Antibodies Or Antigens For Use As Internal Diagnostic Agents (AREA)
Abstract
The invention disclosesAn online soft measurement method for the air intake of a cooling fan section of an indirect air cooling tower comprises the following steps: 1) obtaining the heat exchange coefficient of the cooling triangular radiator of the indirect air cooling system of the research objectk f . 2) According to the structural size provided by the power plant, the windward area is arrangedA n,i Area of heat exchange with the sectorA o,i . 3) And reading out the temperature and other relevant temperatures of the air after entering the cooling fan section according to the temperature measuring point. 4) Calculating the wind speed at the inlet of the sector based on a mathematical theoretical model of heat transferv n,i Further give the air intake of the sectorq v,i . The invention can master the air inlet air speed of each sector of the indirect air cooling system, and has very important practical significance and practical value for the economic and safe operation of the whole indirect air cooling system, especially for preventing the occurrence of freezing accidents of the radiator of the indirect air cooling system in winter.
Description
Technical Field
The invention relates to an online soft measurement method technology for the air intake of cooling fan sections of an indirect air cooling tower, in particular to a method for calculating the air volume of each fan section of an indirect air cooling system when air enters the indirect air cooling system based on a mathematical theoretical model of heat transfer science, and belongs to the technical field of online monitoring.
Background
The indirect air cooling system is gradually widely applied in the areas of 'rich coal and water' in China due to the characteristics of water and electricity saving, low unit coal consumption and the like. The operating characteristics of the indirect air cooling tower determine that the indirect air cooling tower is easy to be interfered by external environment, and a series of problems occur in operation, such as insufficient cooling output in summer, freezing of a radiator in winter and the like, so that the economical efficiency and the safety of unit operation are seriously influenced. The online soft measurement of the air intake of the cooling fan section of the air cooling tower is beneficial to real-time monitoring of the heat exchange condition of the fan section of the air cooling tower, and timely guidance of field workers to control the opening of the louver, especially the situation that the radiator is dangerous to freeze.
In addition, for each cooling sector of the indirect air cooling tower, the flow field at the inlet of the sector is complex, the flow velocity at a certain point changes frequently and is greatly influenced by the change of the flow field, and the windward speed and the intake of the sector are difficult to directly and accurately measure. Moreover, the arrangement of the measuring points is also questionable, the windward air inlet condition of the sector can be reflected most only when the measuring points are arranged, and the measurement of the windward air speed or the air inlet amount of the indirect air cooling tower by using the existing instrument is difficult.
Therefore, the development of a soft measurement method for giving the inlet wind speed of the sector of the indirect air cooling system has very important practical significance and practical value.
Disclosure of Invention
The technical problem is as follows: in order to overcome the defects in the prior art, the invention provides an accurate and easily-obtained soft measurement method for the wind speed at the inlet of the sector of the indirect air cooling system.
The technical scheme is as follows: in order to achieve the aim, the invention provides an online soft measurement method for the air intake of cooling sectors of an indirect air cooling tower, which is used for providing a calculated value of the air speed at the inlet of the cooling sector of the cooling tower of a thermal power generating unit, wherein the cooling tower runs in an indirect air cooling mode, and the air speed at the inlet is the air speed at the inlet of each sector of the indirect air cooling tower; the method comprises the following steps:
And 3, reading out the temperature and other relevant temperatures of the air after entering the cooling fan section according to the temperature measuring point.
Step 4, calculating the wind speed v at the inlet of the fan section based on a mathematical theoretical model of heat transferniFurther give the sector intake qv,i。
In an embodiment of the present invention, the heat exchange coefficient k of the cooling triangular heat sink of the indirect air cooling system in step 1 isfRefers to the convection heat transfer process of forced convection heat transfer between air and the finned tube of the radiatorThe coefficient is influenced by the structural size of the finned tube, the wind speed, dirt in the tube and the like.
The heat exchange process comprises the flowing of the fluid in the pipe to the side wall surface h of the pipeiHeat conduction from the inner wall surface to the outer wall surface of the tube
Outside pipe sidewall to outside fluid hoAnd (4) three links. For the metal heat transfer pipe, because the heat conduction coefficient element is large, the thickness of the pipe wall is small,
the term can be ignored, therefore, the temperature of the circulating water in the pipe is close to the temperature of the pipe wall, namely tw≈tf，twFinger wall temperature, tfWhich refers to the temperature of the water in the tube. At the same time, when hi、hoWhen the difference is large, the k value is mainly determined by the small heat exchange coefficient, and the heat exchange coefficient h of the circulating water in the pipe is thei>>hoTherefore, the total convective heat transfer coefficient is approximately replaced by the air side convective heat transfer coefficient, i.e., kf≈ha。
To obtain the heat convection coefficient h of the air sideaWith inlet wind speed vn,iThe relationship between the two is easy, and the relationship is mainly obtained by the following methods: firstly, the heat radiator fin tube is provided by manufacturers; secondly, the finned tube is obtained by performing a wind tunnel test on the finned tube on site; and thirdly, numerical simulation of the radiator finned tube is carried out by utilizing Ansys.
In an embodiment of the present invention, the frontal area a in step 2n,iThe total area of the air channel in the direction of the louver air inlet of the vertical air entering the No. i sector; the heat exchange area A of the sectoro,iThe total heat exchange area (including the area of the finned tube fins of the radiator) of the air and the finned tube of the radiator with the number i sector through convection heat exchange is indicated. Both quantities are derived from the structural dimensioning of the indirect air cooling system provided by the power plant.
In an embodiment of the present invention, the correlated temperature in step 3 is a temperature t after air enters the sector ia_out,i(ii) a Environment 2Temperature ta_in(ii) a Thirdly, the water temperature t of the circulating water in the sectorw_in,i，tw_out,i。
In an embodiment of the present invention, the mathematical theoretical model of heat transfer in step 4 is:
taking a certain sector formed by a plurality of cooling triangles as a research object, and flushing the heat absorption quantity Q of the finned tube of the sector radiator by aira,iHeat quantity Q of convection heat exchange with the finned tube of the sectorm,iComprises the following steps:
in the formula: cpaAnd ρaThe specific heat capacity and density of air at constant pressure are expressed by the air side inlet temperature, namely the ambient temperature ta_inThe characteristic temperature can be obtained by inquiring a thermophysical property table of the dry air, and the units are J/(kg) K) and kg/m3。
According to conservation of energy, from Qa,i＝Qm,iThe following can be obtained:
the wind speed v of the air entering the No. i sector can be obtainedn,iIn the unit m/s. The air intake q of the sectorv,i＝An,ivn,iUnit m of3/s。
Has the advantages that: according to the invention, on the premise of providing the heat exchange coefficient of the cooling triangular radiator of the indirect air cooling system of a research object and the structural size provided by the power plant, the inlet air speed of the fan section is calculated based on a mathematical theoretical model of heat transfer, and then the air intake of the fan section is provided, so that the inlet air quantity of each fan section of the indirect air cooling system is monitored on line. The online soft measurement of the inlet air quantity of each sector of the indirect air cooling system is realized, the heat exchange condition of the sectors of the air cooling tower can be monitored in real time, and the field work can be guided in time.
Drawings
FIG. 1 is a flow chart of a method of an embodiment of the present invention;
Detailed Description
The present invention will be further described with reference to the following examples and the accompanying drawings.
The embodiment is to calculate the inlet wind speed of No. 2 sector of a SCAL type indirect air cooling system of a certain 600MW unit in Shanxi, which is a research object:
referring to fig. 1, the first step is to obtain the convective heat transfer coefficient k of the radiator of the indirect air cooling systemf. The heat exchange process comprises the flowing of the fluid in the pipe to the side wall surface h of the pipeiHeat conduction from the inner wall surface to the outer wall surface of the tube
Outside pipe sidewall to outside fluid hoAnd (4) three links. For the metal heat transfer pipe, because the heat conduction coefficient element is large, the thickness of the pipe wall is small,
the term can be ignored, therefore, the temperature of the circulating water in the pipe is close to the temperature of the pipe wall, namely tw≈tf，twFinger wall temperature, tfWhich refers to the temperature of the water in the tube. At the same time, when hi、hoWhen the difference is large, the k value is mainly determined by the small heat exchange coefficient, and the heat exchange coefficient h of the circulating water in the pipe is thei>>hoTherefore, the total convective heat transfer coefficient is approximately replaced by the air side convective heat transfer coefficient, i.e., kf≈ha. This example haWith inlet wind speed vn,iThe correlation of (a) is obtained from heat exchange performance parameters of the elliptical finned tube of the radiator provided by the power plant.
Referring to fig. 1, the second step is to collate the relevant areas: the total area A of the air channel in the direction vertical to the air inlet of the louver of No. 2 sectorn,2(ii) a ② total surface area A of air convected with No. 2 sector radiator finned tubeo,2. Both quantities are calculated from the structural dimensions of the indirect air cooling system provided by the power plant.
Referring to fig. 1, the third step is to read the relevant temperature: temperature t after air enters No. 2 sectora_out,2(ii) a Ambient temperature ta_in(ii) a ③ in the sectorCirculating water inlet and outlet water temperature tw_in,2，tw_out,2. The arrangement of temperature measuring points in the indirect air cooling system is easy, and the read numerical value is accurate.
Referring to fig. 1, the fourth step is the inlet wind speed v for air entering sector 2n,2And performing calculation, wherein the calculation steps are as follows:
firstly, a mathematical theoretical model of heat transfer is as follows:
taking No. 2 sector of the unit as a research object, and washing the heat absorption Q of the finned tube of the sector radiator by aira，2Heat Q of convective heat exchange with the finned tubem,2Comprises the following steps:
in the formula: cpaAnd ρaThe specific heat capacity and density of air at constant pressure are expressed by the air side inlet temperature, namely the ambient temperature ta_inThe characteristic temperature can be obtained by inquiring a thermophysical property table of the dry air, and the units are J/(kg) K) and kg/m3。
According to conservation of energy, from Qa,2＝Qm,2The following can be obtained:
the wind speed v of the No. 2 sector of the air entering can be obtainedn,2In the unit m/s. The air intake q of the sectorv.2＝An,2vn,2Unit m of3/s。
Claims (4)
1. An online soft measurement method for the air intake of a cooling fan section of an indirect air cooling tower is characterized by comprising the following steps:
step 1, obtaining the heat exchange coefficient k of a cooling triangular radiator of an indirect air cooling system of a research objectf；
Step 2, arranging the windward area A according to the structural size provided by the power plantn,iHeat exchange area A with sectoro,i；
Step 3, reading out the relevant temperature of the air after entering the cooling fan section according to the temperature measuring point;
step 4, calculating the wind speed v at the inlet of the fan section based on a mathematical theoretical model of heat transfern,iFurther give the sector intake qv,i(ii) a The mathematical theoretical model of heat transfer in the step 4 is as follows:
taking a certain sector formed by a plurality of cooling triangles as a research object, and flushing the heat absorption quantity Q of the finned tube of the sector radiator by aira,iHeat quantity Q of convection heat exchange with the finned tube of the sectorm,iComprises the following steps:
in the formula: c. CpaAnd ρaThe specific heat capacity and density of air at constant pressure are expressed by the air side inlet temperature, namely the ambient temperature ta_inAs characteristic temperature, obtained by looking up the thermo-physical property table of dry air, cpaThe unit is J/(kg K), ρaThe unit is kg/m 3; t is ta_out,iThe temperature of the air after entering the sector i is represented by K; t is ta,iIs the ambient temperature in units of K, tw_in,i、tw_out,iThe water temperature of circulating water in the section i and the water temperature of the inlet and the outlet are K; h isaIs the air side convective heat transfer coefficient; t is twIs the wall temperature;
according to conservation of energy, from Qa,i＝Qm,iObtaining:
obtaining the wind speed v of air entering No. i sectorn,iIn m/s; the air intake q of the sectorv,i＝An,ivn,iUnit m of3/s。
2. The on-line soft measurement method for the intake of the cooling fan section of the indirect air cooling tower as claimed in claim 1, wherein the method comprises the following steps: the heat exchange coefficient k of the cooling triangular radiator of the indirect air cooling system in the step 1fThe heat transfer coefficient is the convective heat transfer coefficient of the forced convective heat transfer process between air and the finned tube of the radiator, and the coefficient is influenced by the structural size of the finned tube, the wind speed and dirt factors in the tube;
the heat exchange process comprises the flowing of the fluid in the pipe to the side wall surface h of the pipeiHeat conduction from the inner wall surface to the outer wall surface of the tube
Outside pipe sidewall to outside fluid hoThree links;
in the case of a metal heat transfer tube,
neglecting the term, the temperature of the circulating water in the pipe is close to the temperature of the pipe wall, i.e. tw≈tf，twFinger wall temperature, tfThe water temperature in the tube; at the same time, when hi、hoWhen the difference is large, kfThe value is mainly determined by the smaller heat exchange coefficient, because the heat exchange coefficient h of the circulating water in the pipei>>hoTherefore, the total convective heat transfer coefficient is approximately replaced by the air side convective heat transfer coefficient, i.e., kf≈ha；
Air side convective heat transfer coefficient haWith inlet wind speed vn,iThe relationship between them is obtained by: firstly, the heat radiator fin tube is provided by manufacturers; secondly, the finned tube is obtained by performing a wind tunnel test on the finned tube on site; and thirdly, numerical simulation of the radiator finned tube is carried out by utilizing Ansys.
3. The on-line soft measurement method for the intake of the cooling fan section of the indirect air cooling tower as claimed in claim 1, wherein the method comprises the following steps: the frontal area A in the step 2n,iThe total area of the air channel in the direction of the louver air inlet of the vertical air entering the No. i sector; the heat exchange area A of the sectoro,iThe total heat exchange area of the air and the finned tube of the radiator with the number i sector in the convective heat exchange mode comprises the area of the finned tube of the radiator; structural dimension arrangement of indirect air cooling system provided by power plant for fin area of finned tube of radiatorAnd (6) obtaining.
4. The on-line soft measurement method for the intake of the cooling fan section of the indirect air cooling tower as claimed in claim 1, wherein the method comprises the following steps: the relevant temperature in the step 3 comprises the temperature t of air after the air enters the sector ia_out,i(ii) a Ambient temperature ta_in(ii) a Thirdly, the temperature t of the circulating water inlet in the sectorw_in,iWater temperature t at the outlet of the circulating water in the sectorw_out,i。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710298885.1A CN107133468B (en) | 2017-04-28 | 2017-04-28 | Online soft measurement method for air intake of cooling fan section of indirect air cooling tower |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710298885.1A CN107133468B (en) | 2017-04-28 | 2017-04-28 | Online soft measurement method for air intake of cooling fan section of indirect air cooling tower |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN107133468A CN107133468A (en) | 2017-09-05 |
| CN107133468B true CN107133468B (en) | 2020-10-23 |
Family
ID=59715260
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710298885.1A Active CN107133468B (en) | 2017-04-28 | 2017-04-28 | Online soft measurement method for air intake of cooling fan section of indirect air cooling tower |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN107133468B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108520095B (en) * | 2018-03-07 | 2021-06-01 | 中国水利水电科学研究院 | Method for forecasting water temperature in base pipe of indirect air-cooling radiator |
| CN108760086B (en) * | 2018-05-24 | 2019-10-25 | 河北博为电气股份有限公司 | A kind of indirect measurement method of indirect air cooling system radiator tube fluid temperature |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101082533A (en) * | 2007-07-09 | 2007-12-05 | 北京航空航天大学 | Simulate platform suitable for heat power plant hollow cold tower thermal state flow field structure and testing method |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140260507A1 (en) * | 2013-03-15 | 2014-09-18 | General Electric Company | Pulse duration extender |
| CN106126864B (en) * | 2016-07-20 | 2021-05-18 | 中国核电工程有限公司 | Indirect air cooling system design and calculation method based on component thermal resistance characteristics |
-
2017
- 2017-04-28 CN CN201710298885.1A patent/CN107133468B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101082533A (en) * | 2007-07-09 | 2007-12-05 | 北京航空航天大学 | Simulate platform suitable for heat power plant hollow cold tower thermal state flow field structure and testing method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN107133468A (en) | 2017-09-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103293013B (en) | A kind of cooling tower thermal performance appraisal procedure and system | |
| CN106547945B (en) | Energy efficiency testing method applied to triple-generation regional energy supply system | |
| CN102338568A (en) | Online monitoring system and method for performance of condenser in power plant based on cleanness coefficient index | |
| Gao et al. | A study on thermal performance of a novel glazed transpired solar collector with perforating corrugated plate | |
| Wu et al. | Modeling the performance of the indirect dry cooling system in a thermal power generating unit under variable ambient conditions | |
| CN106403422A (en) | Defrosting start point judgment method and defrosting start point judgment system for multi-loop heat exchanger of air source heat pump | |
| He et al. | Influence from the rotating speed of the windward axial fans on the performance of an air-cooled power plant | |
| CN104360984B (en) | One kind is based on the lower cooling tower filler performance calculation method of Two point boundary value measurement | |
| CN107133468B (en) | Online soft measurement method for air intake of cooling fan section of indirect air cooling tower | |
| CN111401686A (en) | Method and device for monitoring dust and dirt condition of air cooling radiating fin | |
| Wang et al. | Anti-freezing of air-cooled heat exchanger by switching off sectors | |
| CN103063354A (en) | Confirming method for turbine standard backpressure in thermal power generating unit energy consumption assessment and coal consumption check test | |
| Dang et al. | Crosswind influence on cooling capacity in different zones for high level water collecting wet cooling towers based on field test | |
| CN109163596A (en) | A kind of novel flow-disturbing fin | |
| CN104777008A (en) | Performance simulation testing experimental device for power plant smoke waste heat utilizing system | |
| CN108021742A (en) | A kind of steam heating pipeline steady-state operating condition method of estimation for considering hydrophobic model | |
| CN104298888B (en) | Fan coil cold measuring method based on flow-cold relation model | |
| CN102494895B (en) | Analyzing method for energy saving and optimization of steam turbine set of power station | |
| CN203479550U (en) | System suitable for testing heat transfer and resistance characteristics of heat exchanger of large-scale generating equipment | |
| CN204514629U (en) | A kind of power-plant flue gas bootstrap system performance simulation experimental apparatus for testing | |
| CN208887443U (en) | A kind of novel flow-disturbing fin | |
| CN205714775U (en) | A kind of water ring vacuum pump monitor control system | |
| CN108760086B (en) | A kind of indirect measurement method of indirect air cooling system radiator tube fluid temperature | |
| Li et al. | Numerical method and analysis of a tube indirect evaporative cooler | |
| CN109522644A (en) | A kind of enhanced heat exchange surface comprehensive performance evaluation method |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |