CN109470741A - A kind of grease thermal resistance measurement device and grease thermal resistance calculation method - Google Patents
A kind of grease thermal resistance measurement device and grease thermal resistance calculation method Download PDFInfo
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- CN109470741A CN109470741A CN201811606907.7A CN201811606907A CN109470741A CN 109470741 A CN109470741 A CN 109470741A CN 201811606907 A CN201811606907 A CN 201811606907A CN 109470741 A CN109470741 A CN 109470741A
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- 239000004519 grease Substances 0.000 title claims abstract description 71
- 238000005259 measurement Methods 0.000 title claims abstract description 51
- 238000004364 calculation method Methods 0.000 title claims abstract description 12
- 230000001105 regulatory effect Effects 0.000 claims abstract description 29
- 239000000446 fuel Substances 0.000 claims abstract description 26
- 238000010438 heat treatment Methods 0.000 claims description 16
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 14
- 239000004973 liquid crystal related substance Substances 0.000 claims description 11
- 239000010410 layer Substances 0.000 claims description 6
- 239000011241 protective layer Substances 0.000 claims description 5
- 239000000463 material Substances 0.000 claims description 4
- 229910000831 Steel Inorganic materials 0.000 claims description 3
- 239000010959 steel Substances 0.000 claims description 3
- 230000005619 thermoelectricity Effects 0.000 claims description 2
- 239000012530 fluid Substances 0.000 claims 1
- 229920002635 polyurethane Polymers 0.000 claims 1
- 239000004814 polyurethane Substances 0.000 claims 1
- 239000003921 oil Substances 0.000 description 104
- 238000000034 method Methods 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 3
- 238000001816 cooling Methods 0.000 description 2
- 238000000691 measurement method Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 230000001186 cumulative effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000012208 gear oil Substances 0.000 description 1
- WABPQHHGFIMREM-UHFFFAOYSA-N lead(0) Chemical compound [Pb] WABPQHHGFIMREM-UHFFFAOYSA-N 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000001050 lubricating effect Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 230000002285 radioactive effect Effects 0.000 description 1
- 238000001028 reflection method Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/20—Investigating or analyzing materials by the use of thermal means by investigating the development of heat, i.e. calorimetry, e.g. by measuring specific heat, by measuring thermal conductivity
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- Investigating Or Analyzing Materials Using Thermal Means (AREA)
Abstract
The invention discloses a kind of grease thermal resistance measurement devices, including fuel feed pump (13), the oil inlet of the fuel feed pump (13) is connected with the oil outlet of oil pump (14), the oil inlet of the oil pump (14) is connected with the oil outlet of oil cooler (18), the oil inlet of the oil cooler (18) is connected with the oil outlet of oil return pipe (17), it is parallel with upper channel measuring section and lower channel measuring section between oil return pipe (17) oil inlet and the oil outlet of the fuel feed pump (13), is provided with filter (12) and total regulating valve on the fuel feed pump (13)；Shut-off valve (16) are provided on the oil return pipe (17).The invention also discloses a kind of grease thermal resistance calculation methods of grease thermal resistance measurement device.The present invention is according to heat transfer principle, analog horizontal tube, bend pipe, vertical tube operating condition, measurement accuracy height.
Description
Technical field
The present invention relates to a kind of grease thermal resistance measurement device and grease thermal resistance calculation methods, belong to thermal resistance measurement technology neck
Domain.
Background technique
The various heat exchangers involved in fuel supply and lubricating system, presence and accumulation at any time due to grease influence
Heat transfer coefficient, and then influence heat exchange amount gently then causes oil temperature deviation, pump consumption to increase, influences production equipment and work normally, heavy then lead
Metal overtemperature is caused, equipment life is influenced, even causes major accident.
Grease thermal resistance measurement has the direct method of measurement and the indirect method of measurement.The direct method of measurement measures Grease stain thickness, then root
Grease thermal resistance is calculated according to the thermal coefficient of grease, specific method has optical method, radioactive method, pulse reflection method etc., but data are not
Ideal, cost height；The indirect method of measurement often uses heat transfer coefficient method, and current measuring system precision is poor, data stability is bad, not
Fully considering oily speed influences, is excessively complicated.
Summary of the invention
The technical problem to be solved by the invention is to provide a kind of according to heat transfer principle, analog horizontal tube, bend pipe,
Vertical tube operating condition, the high grease thermal resistance measurement device of measurement accuracy；
The present invention also provides a kind of grease thermal resistance calculation method of grease thermal resistance measurement device, which considers oily speed to oil
The influence of dirty thermal resistance measurement precision, and analog horizontal tube, bend pipe, vertical tube operating condition, measurement accuracy are high.
In order to solve the above technical problems, the technical solution adopted by the present invention are as follows:
A kind of grease thermal resistance measurement device, including fuel feed pump, the oil inlet of the fuel feed pump are connected with the oil outlet of oil pump,
The oil inlet of the oil pump is connected with the oil outlet of oil cooler, and the oil inlet of the oil cooler is connected with the oil outlet of oil return pipe,
Upper channel measuring section and lower channel measuring section are parallel between the oil return pipe oil inlet and the oil outlet of the fuel feed pump；
Filter and total regulating valve are provided on the fuel feed pump；
Shut-off valve is provided on the oil return pipe；
The upper channel measuring section and lower channel measuring section include the branch's regulating valve being connected with total regulating valve, institute
It states branch's regulating valve to be connected with inlet tube, the inlet tube is connected with flowmeter, and the flowmeter is connected with L-type bend pipe, the L
Type bend pipe includes the horizontal segment, bend loss and vertical section of integrally connected, and the horizontal segment is connected with the flowmeter；
The horizontal segment, bend loss and vertical section successively include oil pipe, insulating layer and protective layer from inside to outside；The water
It is provided with heater in the middle part of the oil pipe of flat section, bend loss and vertical section, the horizontal segment at the heater both ends and vertical
Thermocouple and thermal resistance are provided on the oil pipe of section；
Two vertical sections pass through check-valves and are connected with oil return pipe；
The flowmeter, thermocouple, heater, thermal resistance, shut-off valve, oil pump are connected with the controller of display instrument；Institute
It states and is provided with liquid crystal display on display instrument, the liquid crystal display is connected with the controller.Liquid crystal display display mass flow (kg/min),
Oil speed c (m/s), grease thermal resistance Rx(m2℃/W)。
What flow measurement obtained is volume flow, i.e. meter readings flow V, and unit L/min, the invention shows quality streams
Amount more has practicability, and mass flow is calculated according to the volume flow of flowmeter, oil density.
The thermocouple and thermal resistance are arranged in the two sides in tubing diameter direction, the i.e. thermocouple and heat of same position
Resistance position is corresponding.
Thermocouple is inserted into inside oil pipe, and for measuring oil temperature, thermocouple uses the armouring of East Platform Xin Rui Instrument Corporation production
Thermocouple, model WRPK, Graduation Number S, 0~1350 DEG C of measurement range, allowable error ± 0.5 DEG C, outer diameter 2mm.
Thermal resistance is attached to oil pipe surface, and for measuring oil pipe wall temperature, thermal resistance is using the double rising sun film-type copper resistances in Shanghai, type
Number WZC, measurement range -50~150 DEG C, allowable error ± (0.30+0.006t) DEG C.
The shut-off valve is connected with the check-valves of the upper channel measuring section and lower channel measuring section respectively by three-way connection
It connects.
Total regulating valve passes through three-way connection branch's tune with the upper channel measuring section and lower channel measuring section respectively
Valve is saved to be connected.
The fuel feed pump, oil return pipe and oil pipe are DN25 steel pipe.In addition to horizontal segment, bend loss, vertical section, other oil pipes
Part is not kept the temperature, and fuel feed pump, oil return pipe and oil pipe form an excessively oily access.
The material of the insulating layer is polyurathamc.
The oil cooler is serpentine heat exchanger, cylindrical, normal pressure, and the setting of serpentine heat exchanger top is useful
In being provided with cold water pipe in the fuel feed hole for being inserted into the oil return pipe, the oil cooler, the cold water pipe is connected to water.
Fuel feed pump from oil cooler bottom draw, be furnished with oil pump, filter, total regulating valve, by three-way connection respectively with it is upper
Channel measurement section, the connection of branch's regulating valve of lower channel measuring section.Oil return pipe is furnished with shut-off valve, is separately connected by three-way connection
The check-valves of upper channel measuring section, lower channel measuring section finally enters the upper space of oil cooler.In oil cooler, oil is cold
Water pipe cooling cooling.
The elliptic gear flow sensor that the flowmeter uses instrument head factory in Hefei to produce, model LC, teletransmission, precision ±
0.5%, DN25, medium temperature -20~80 DEG C, highest pressure-bearing 1.6MPa.
Heater uses insulated heating wire, is wrapped in oil pipe surface, controls heating and measurement electric thermal power by display instrument.
Oil pump reaches the gear oil pump of pump valve Manufacturing Co., Ltd production, model WCB-75P, stainless steel material, stream using spring
75L/min, pressure head 30m, electrical power 750W are measured, working oil temperature is not higher than 80 DEG C.
Shut-off valve using upper Haitai lead to bellows stop valve, -29~350 DEG C, highest pressure-bearing 1.6MPa, bore 25mm.
Branch's regulating valve use Shanghai Bei Site T40 plunger hand regulating valve, -29~150 DEG C, highest pressure-bearing
1.6MPa, bore 25mm.
According to meter readings and subsequent thermocouple readings, the mass flow of oil can be obtained；Measure the heating of horizontal segment
The electric thermal power of device, oil temperature liter, oil-pipe external wall mean temperature can calculate entire thermal resistance, convective heat transfer resistance, due to thermally conductive heat
Resistance is certain, finally calculates grease thermal resistance.Bend loss, vertical section are as horizontal segment measuring principle.
A kind of grease thermal resistance calculation method of grease thermal resistance measurement device, comprising the following steps:
For the horizontal segment of the above channel measurement section, the calculation method of the grease thermal resistance of the horizontal segment of upper channel measuring section
Are as follows:
The electric current of the heater on the horizontal segment of upper channel measuring section is adjusted, the oil temperature liter Δ t=before and after heater is controlled
t2-t1, wherein t2The temperature after heating up is represented, wherein t1Temperature before representing heating, Δ t represent heat transfer temperature difference, and Δ t is no more than
10 DEG C, measure the electric thermal power N of heater；The tube wall temperature of oil pipe before and after heater is measured by thermal resistance respectively, respectively
For tW1、tW2, pipe outer wall mean temperature is tW, tW=0.5 (tW1+tW2)；The logarithmic mean temperature difference (LMTD) of horizontal segment at this time are as follows:
In formula (1), subscript lm represents logarithmic mean, and Δ t represents heat transfer temperature difference, (Δ t)lmRepresent logarithmic mean heat transfer temperature
Difference, abbreviation logarithmic mean temperature difference (LMTD), logarithmic mean temperature difference (LMTD) more meet engineering reality than arithmetic mean temperature difference；
Since the length and heating surface (area) (HS A of horizontal segment are certain, therefore the thermal conduction resistance R of horizontal segment0Centainly, the heat transfer of horizontal segment
Coefficient is that K is certain, then can calculate overall thermal resistance R:
In formula (2), R represents the overall thermal resistance of horizontal segment；N represents the electric thermal power of heater；RxRepresent grease thermal resistance；
RαRepresent the convective heat transfer resistance of horizontal segment；
From formula (2) as long as it is found that calculating R, Rα, can know grease thermal resistance Rx；R=1/K；R is calculated belowα；
According to meter readings flow V, unit L/min, pipe aperture d, unit mm, oily speed c, unit m/ are calculated
S:
Oily mean temperature t=0.5 (t1+t2), oil density ρ is checked in from oily physical parameter table according to t, ρ unit is kg/L, leads
Hot coefficient lambda, kinematic viscosity, Pr number；The channel capacity m of upper channel measuring section is calculated using m=ρ V formula, and the unit of m is kg/
min；Reynolds number Re can be calculated according to given data, Knoop number Nu can be calculated using following formula (4):
Nu=0.023Re0.8Pr0.4 (4)
Due to Nu=α d/ λ, wherein α represents convection transfer rate；Therefore convective heat transfer resistance RαIt is calculated with following formula (5):
In formula (5), α represents convection transfer rate；
It can finally obtain, grease thermal resistance Rx=R-R0-Rα。
Compared with the prior art, the invention has the benefit that
1. can on-line measurement grease thermal resistance, dummy level pipe, bend pipe, vertical tube operating condition, measurement accuracy is higher.
2. practical oil speed or other oily speed can be used to measure grease thermal resistance, its rule that changes with time is studied.
3. selecting sophisticated sensor, various aspects take measures to limit measurement error, and measurement method is proper.
4. grease thermal resistance measurement device for the first time in use, grease thermal resistance be 0, can be used to demarcate display instrument.
This measuring device and its method can measure the grease thermal resistance of lower horizontal tube different in flow rate, bend pipe, vertical tube, can be used to
The increase rule of grease thermal resistance at any time is studied, since measurement method is proper, and takes many kinds of measures limitation measurement error, because
And grease thermal resistance measurement precision is relatively high, can satisfy the measurement and control needs of Thermal Equipment.
Detailed description of the invention
Fig. 1 is the structural diagram of the present invention；
Wherein, 1- branch regulating valve；2- flowmeter；3- thermocouple；4- horizontal segment；5- vertical section；6- check-valves；7- heating
Device；8- bend loss；9- inlet tube；10- protective layer；11- thermal resistance；12- filter；13- fuel feed pump；14- oil pump；15- cold water
Pipe；16- shut-off valve；17- oil return pipe；18- oil cooler；19- display instrument；20- upper channel button；21- lower channel button；22- liquid
Crystalline substance screen；23- power knob；24- horizontal segment button；25- bend loss button；26- vertical section button.
Specific embodiment
The present invention will be further explained with reference to the accompanying drawing.
Shown in Fig. 1, a kind of grease thermal resistance measurement device (divides upper channel measuring section and lower channel by fuel feed pump 13, measuring section
Measuring section is arranged symmetrically), oil return pipe 17, oil cooler 18, display instrument 19 form.Measuring section includes branch's regulating valve 1, inlet tube
9, flowmeter 2, horizontal segment 4, bend loss 8, vertical section 5 and check-valves 6.
The oil inlet of the fuel feed pump 13 is connected with the oil outlet of oil pump 14, the oil inlet and oil cooler 18 of the oil pump 14
Oil outlet be connected, the oil inlet of the oil cooler 18 is connected with the oil outlet of oil return pipe 17,17 oil inlet of oil return pipe and
Upper channel measuring section and lower channel measuring section are parallel between the oil outlet of the fuel feed pump 13；
Filter 12 and total regulating valve are provided on the fuel feed pump 13；
Shut-off valve 16 is provided on the oil return pipe 17；
The upper channel measuring section and lower channel measuring section include the branch's regulating valve 1 being connected with total regulating valve,
Branch's regulating valve 1 is connected with inlet tube 9, and the inlet tube 9 is connected with flowmeter 2, the flowmeter 2 and L-type bend pipe phase
Even, the L-type bend pipe includes the horizontal segment 4, bend loss 8 and vertical section 5 of integrally connected, the horizontal segment 4 and the flowmeter 2
It is connected；
The horizontal segment 4, bend loss 8 and vertical section 5 successively include oil pipe, insulating layer and protective layer 10 from inside to outside；
Heater 7, the water at 7 both ends of heater are provided in the middle part of the oil pipe of the horizontal segment 4, bend loss 8 and vertical section 5
Thermocouple 3 and thermal resistance 11 are provided on the oil pipe of flat section 4 and vertical section 5；
Two vertical sections 5 are connected by check-valves 6 with oil return pipe 17；
Controller, flowmeter 2, thermocouple 3, heater 7, thermal resistance 11, shut-off valve 16, oil pump 14 are equipped in display instrument 19
It is connect with controller, liquid crystal display 22 is additionally provided on display instrument 19, liquid crystal display 22 is connect with controller.Liquid crystal display 22 shows quality
Flow (kg/min), oily speed (m/s), grease thermal resistance (m2℃/W)。
Fuel feed pump 13 is drawn from 18 bottom of oil cooler, is furnished with oil pump 14, filter 12, and total regulating valve passes through three-way connection
It is connect respectively with branch's regulating valve 1 of upper channel measuring section and lower channel measuring section.Oil return pipe 17 is furnished with shut-off valve 16, passes through three
Pass joint is separately connected the check-valves 6 of upper channel measuring section and lower channel measuring section, finally enters the upper space of oil cooler 18.
In oil cooler 18, oil is cooled by cold water pipe 15.
All oil pipes are all made of DN25 steel pipe, in addition to horizontal segment 4, bend loss 8, vertical section 5, do not keep the temperature.Inlet tube 9 is left
Bian Jie branch regulating valve 1, the right connects flowmeter 2.L-type bend pipe is oil pipe, polyurathamc insulating layer and protective layer from inside to outside
10, horizontal segment 4 is from left to right followed successively by thermocouple 3, thermal resistance 11, heater 7, thermocouple 3, thermal resistance 11.
8 having heaters 7 of bend loss.
5 structure of vertical section is similar with horizontal segment 4, is followed successively by thermocouple 3, thermal resistance 11, heater 7, thermoelectricity from top to bottom
Even 3, thermal resistance 11.To reduce measurement error, thermal resistance 11 and thermocouple 3 are arranged in the two sides in tubing diameter direction as far as possible,
I.e. position is preferably corresponding.
Positioned at the thermocouple 3 and thermal resistance 11 on 4 right side of horizontal segment and the thermocouple 3 and thermal resistance of 5 lower section of vertical section
11, it can also be used in the measurement of bend loss 8 respectively.
Thermocouple 3 is inserted into inside oil pipe, for measuring oil temperature, model WRPK；
Thermal resistance 11 is attached to oil pipe surface, for measuring oil pipe wall temperature.
2 model LC of flowmeter.
Heater 7 uses insulated heating wire, is wrapped in oil pipe surface, controls heating and measurement electric heating function by display instrument 19
Rate.
14 model WCB-75P of oil pump, stainless steel material.
Oil cooler 18 is serpentine heat exchanger, cylindrical, and normal pressure above has fuel feed hole, for being inserted into oil return pipe 17, cold water
Pipe 15 can be connected to water.
The tolerable temperature of shut-off valve 16 is -29~350 DEG C, highest pressure-bearing 1.6MPa, bore 25mm.
The tolerable temperature of branch's regulating valve 1 is -29~150 DEG C, highest pressure-bearing 1.6MPa, bore 25mm.
The course of work and principle of the invention is as follows:
When measuring oil pipe tube wall grease thermal resistance, upper channel measuring section oil speed is controlled in normal flow range, i.e. 2~3m/s,
Lower, the about 1~1.5m/s of the oily speed of lower channel measuring section.Measuring device can measure upper channel measuring section and lower channel measuring section simultaneously
Horizontal segment 4, bend loss 8 and vertical section 5 grease thermal resistance.
It is read according to the reading of flowmeter 2 and subsequent thermocouple 3, the mass flow of oil can be obtained；Measure adding for horizontal segment 4
The electric thermal power of hot device 7, oil temperature liter, oil-pipe external wall mean temperature can calculate entire thermal resistance, convective heat transfer resistance, due to leading
Thermal resistance is certain, finally calculates grease thermal resistance.Bend loss 8, vertical section 5 are as the measuring principle of horizontal segment 4.
The power knob 23 of display instrument 19 is pressed, total regulating valve, shut-off valve 16 are opened, and oil pump 14 starts, and oil circuit starts to follow
Ring, the work of cold water pipe 15, flowmeter 2 work, each temperature sensor work.Upper channel button 20 is pressed, the display of liquid crystal display 22 is " tired
Count working time (h), upper channel mass flow (kg/min), oil speed (m/s) ", 1 aperture of branch's regulating valve adjustment oil can be changed
Speed；Press lower channel button 21, the display of liquid crystal display 22 " cumulative operation time, lower channel mass flow (kg/min), oily speed (m/
S) ", 1 aperture of branch's regulating valve adjustment oil speed can be changed.Display instrument 19 cannot show the data in upper and lower channel simultaneously.
In the case where pressing upper channel button 20, successively presses horizontal segment button 24, bend loss button 25, vertical section and press
Button 26, liquid crystal display 22 show " horizontal segment flow velocity grease thermal resistance ", " horizontal segment flow velocity grease thermal resistance respectively；Bend loss flow velocity grease
Thermal resistance ", " horizontal segment flow velocity grease thermal resistance；Bend loss flow velocity grease thermal resistance；Vertical section flow velocity grease thermal resistance "；Some is sprung back to press
Button, corresponding display disappear.Lower channel shows similar with upper channel.
A kind of grease thermal resistance calculation method of grease thermal resistance measurement device, comprising the following steps:
For the horizontal segment 4 of the above channel measurement section, the calculation method of the grease thermal resistance of the horizontal segment 4 of upper channel measuring section
Are as follows:
The electric current of the heater 7 on the horizontal segment 4 of upper channel measuring section is adjusted, the oil temperature of 7 front and back of control heater rises Δ t
=t2-t1, wherein t2The temperature after heating up is represented, wherein t1Temperature before representing heating, Δ t represent heat transfer temperature difference, and Δ t does not surpass
10 DEG C are crossed, the electric thermal power N of heater 7 is measured；The tube wall temperature of the oil pipe of 7 front and back of heater is surveyed by thermal resistance 11 respectively
Amount, respectively tW1、tW2, pipe outer wall mean temperature is tW, tW=0.5 (tW1+tW2)；The logarithmic mean temperature difference (LMTD) of horizontal segment 4 at this time
Are as follows:
In formula (1), subscript lm represents logarithmic mean, and Δ t represents heat transfer temperature difference, (Δ t)lmRepresent logarithmic mean heat transfer temperature
Difference, abbreviation logarithmic mean temperature difference (LMTD), logarithmic mean temperature difference (LMTD) more meet engineering reality than arithmetic mean temperature difference；
Since the length and heating surface (area) (HS A of horizontal segment 4 are certain, therefore the thermal conduction resistance R of horizontal segment 40Centainly, horizontal segment 4
Heat transfer coefficient is that K is certain, then can calculate overall thermal resistance R:
In formula (2), R represents the overall thermal resistance of horizontal segment 4；N represents the electric thermal power of heater 7；RxRepresent grease heat
Resistance；RαRepresent the convective heat transfer resistance of horizontal segment 4；
From formula (2) as long as it is found that calculating R, Rα, can know grease thermal resistance Rx；R=1/K；R is calculated belowα；
Flow V, unit L/min, pipe aperture d, unit mm are read according to flowmeter 2, calculates oily speed c, unit is
M/s:
Oily mean temperature t=0.5 (t1+t2), oil density ρ is checked in from oily physical parameter table according to t, ρ unit is kg/L, leads
Hot coefficient lambda, kinematic viscosity, Pr number；The channel capacity m of upper channel measuring section is calculated using m=ρ V formula, and the unit of m is kg/
min；Reynolds number Re can be calculated according to given data, Knoop number Nu can be calculated using following formula (4):
Nu=0.023Re0.8Pr0.4 (4)
Due to Nu=α d/ λ, wherein α represents convection transfer rate；Therefore convective heat transfer resistance RαIt is calculated with following formula (5):
In formula (5), α represents convection transfer rate；
It can finally obtain, grease thermal resistance Rx=R-R0-Rα。
This grease thermal resistance measurement device and grease thermal resistance calculation method, since thermal conduction resistance is smaller, it is contemplated that actual conditions
Under convective heat transfer resistance, while using high-precision temperature sensor, thus measurement accuracy is relatively high.It is surveyed in grease thermal resistance
Measure device for the first time in use, grease thermal resistance be 0, can be used to demarcate display instrument；Alternatively, grease thermal resistance measurement device is longer in use
After time, thorough alkali cleaning, grease thermal resistance is regarded as 0 at this time, can be used to demarcate display instrument.
The above is only a preferred embodiment of the present invention, it should be pointed out that: for the ordinary skill people of the art
For member, various improvements and modifications may be made without departing from the principle of the present invention, these improvements and modifications are also answered
It is considered as protection scope of the present invention.
Claims (10)
1. a kind of grease thermal resistance measurement device, it is characterised in that: including fuel feed pump (13), the oil inlet of the fuel feed pump (13) with
The oil outlet of oil pump (14) is connected, and the oil inlet of the oil pump (14) is connected with the oil outlet of oil cooler (18), the oil cooler
(18) oil inlet is connected with the oil outlet of oil return pipe (17), and oil return pipe (17) oil inlet goes out with the fuel feed pump (13)
Upper channel measuring section and lower channel measuring section are parallel between hydraulic fluid port；
Filter (12) and total regulating valve are provided on the fuel feed pump (13)；
Shut-off valve (16) are provided on the oil return pipe (17)；
The upper channel measuring section and lower channel measuring section include the branch's regulating valve (1) being connected with total regulating valve, institute
It states branch's regulating valve (1) to be connected with inlet tube (9), the inlet tube (9) is connected with flowmeter (2), the flowmeter (2) and L
Type bend pipe is connected, and the L-type bend pipe includes the horizontal segment (4), bend loss (8) and vertical section (5) of integrally connected, the horizontal segment
(4) it is connected with the flowmeter (2)；
The horizontal segment (4), bend loss (8) and vertical section (5) successively include oil pipe, insulating layer and protective layer from inside to outside
(10)；Heater (7), the heater are provided in the middle part of the oil pipe of the horizontal segment (4), bend loss (8) and vertical section (5)
(7) thermocouple (3) and thermal resistance (11) are provided on the horizontal segment (4) at both ends and the oil pipe of vertical section (5)；
Two vertical sections (5) are connected by check-valves (6) with oil return pipe (17)；
The flowmeter (2), thermocouple (3), heater (7), thermal resistance (11), shut-off valve (16), oil pump (14) with display
The controller of instrument (19) is connected；It is provided with liquid crystal display (22) on the display instrument (19), the liquid crystal display (22) and the control
Device is connected.
2. a kind of grease thermal resistance measurement device according to claim 1, it is characterised in that: the thermocouple (3) and thermoelectricity
Resistance (11) is arranged in the two sides in tubing diameter direction, i.e. the thermocouple (3) of same position and thermal resistance (11) position is opposite
It answers.
3. a kind of grease thermal resistance measurement device according to claim 1, it is characterised in that: the shut-off valve (16) passes through three
Pass joint is connect with the check-valves (6) of the upper channel measuring section and lower channel measuring section respectively.
4. a kind of grease thermal resistance measurement device according to claim 1, it is characterised in that: total regulating valve passes through threeway
Connector is connected with branch's regulating valve (1) of the upper channel measuring section and lower channel measuring section respectively.
5. a kind of grease thermal resistance measurement device according to claim 1, it is characterised in that: the fuel feed pump (13), oil return
It manages (17) and oil pipe is DN25 steel pipe.
6. a kind of grease thermal resistance measurement device according to claim 1, it is characterised in that: the material of the insulating layer is hair
Steep polyurethane.
7. a kind of grease thermal resistance measurement device according to claim 1, it is characterised in that: the oil cooler (18) is snakelike
Pipe heat exchanger, serpentine heat exchanger top are provided with the fuel feed hole for being inserted into the oil return pipe (17), the oil
It is provided with cold water pipe (15) in cooler (18), the cold water pipe (15) is connected to water.
8. a kind of grease thermal resistance measurement device according to claim 1, it is characterised in that: flowmeter (2) model
LC。
9. a kind of grease thermal resistance measurement device according to claim 1, it is characterised in that: the heater (7) is exhausted
Edge heating wire is wrapped in the oil pipe outer surface.
10. a kind of grease thermal resistance calculation method of grease thermal resistance measurement device as described in any one of claims 1 to 9 is used,
It is characterized by comprising following steps:
The calculation method of the grease thermal resistance of the horizontal segment (4) of upper channel measuring section are as follows:
Adjust the electric current of the heater (7) on the horizontal segment (4) of upper channel measuring section, the oil temperature liter before and after control heater (7)
Δ t=t2-t1, wherein t2The temperature after heating up is represented, wherein t1Temperature before representing heating, Δ t represent heat transfer temperature difference, and Δ t is not
More than 10 DEG C, the electric thermal power N of heater (7) is measured；The tube wall temperature of oil pipe before and after heater (7) is respectively by thermal resistance
(11) it measures, respectively tW1、tW2, pipe outer wall mean temperature is tW, tW=0.5 (tW1+tW2)；The logarithm of horizontal segment (4) is flat at this time
Mean temperature difference are as follows:
In formula (1), subscript lm represents logarithmic mean, and Δ t represents heat transfer temperature difference, (Δ t)lmLogarithmic mean heat transfer temperature difference is represented, letter
Claim logarithmic mean temperature difference (LMTD), logarithmic mean temperature difference (LMTD) more meets engineering reality than arithmetic mean temperature difference；
Since the length and heating surface (area) (HS A of horizontal segment (4) are certain, therefore the thermal conduction resistance R of horizontal segment (4)0Centainly, horizontal segment (4)
Heat transfer coefficient is that K is certain, then can calculate overall thermal resistance R:
In formula (2), R represents the overall thermal resistance of horizontal segment (4)；N represents the electric thermal power of heater (7)；RxRepresent grease heat
Resistance；RαRepresent the convective heat transfer resistance of horizontal segment (4)；
From formula (2) as long as it is found that calculating R, Rα, can know grease thermal resistance Rx；R=1/K；R is calculated belowα；
Flow V, unit L/min, pipe aperture d, unit mm are read according to flowmeter (2), calculates oily speed c, unit m/
S:
Oily mean temperature t=0.5 (t1+t2), oil density ρ is checked in from oily physical parameter table according to t, ρ unit is kg/L, thermally conductive system
Number λ, kinematic viscosity, Pr number；The channel capacity m of upper channel measuring section is calculated using m=ρ V formula, and the unit of m is kg/min；Root
Reynolds number Re can be calculated according to given data, Knoop number Nu can be calculated using following formula (4):
Nu=0.023Re0.8Pr0.4 (4)
Due to Nu=α d/ λ, wherein α represents convection transfer rate；Therefore convective heat transfer resistance RαIt is calculated with following formula (5):
In formula (5), α represents convection transfer rate；
It can finally obtain, grease thermal resistance Rx=R-R0-Rα。
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| CN102135511A (en) * | 2010-12-29 | 2011-07-27 | 浙江银轮机械股份有限公司 | Method and device for testing heat transfer performance of fin surface of plate-fin heat exchanger |
| KR101209585B1 (en) * | 2012-08-07 | 2012-12-07 | 한국지질자원연구원 | Ground thermal conductivity measuring equipment |
| CN105158293A (en) * | 2015-10-10 | 2015-12-16 | 中国石油化工股份有限公司 | Visual testing system for heat transfer and scale inhibition property of oil sealing water cooler of oil refining device |
| CN207007755U (en) * | 2017-03-14 | 2018-02-13 | 中国石油化工股份有限公司 | A kind of recycle oil evaluation of scale inhibitor experimental provision |
| CN209296634U (en) * | 2018-12-27 | 2019-08-23 | 南京林业大学 | A kind of grease thermal resistance measurement device |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102135511A (en) * | 2010-12-29 | 2011-07-27 | 浙江银轮机械股份有限公司 | Method and device for testing heat transfer performance of fin surface of plate-fin heat exchanger |
| KR101209585B1 (en) * | 2012-08-07 | 2012-12-07 | 한국지질자원연구원 | Ground thermal conductivity measuring equipment |
| CN105158293A (en) * | 2015-10-10 | 2015-12-16 | 中国石油化工股份有限公司 | Visual testing system for heat transfer and scale inhibition property of oil sealing water cooler of oil refining device |
| CN207007755U (en) * | 2017-03-14 | 2018-02-13 | 中国石油化工股份有限公司 | A kind of recycle oil evaluation of scale inhibitor experimental provision |
| CN209296634U (en) * | 2018-12-27 | 2019-08-23 | 南京林业大学 | A kind of grease thermal resistance measurement device |
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