CN105136342B - The system and method for heat exchanger heat exchange amount measurement accuracy is improved under the conditions of tepor difference - Google Patents
The system and method for heat exchanger heat exchange amount measurement accuracy is improved under the conditions of tepor difference Download PDFInfo
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Abstract
The invention discloses the system and method that heat exchanger heat exchange amount measurement accuracy is improved under the conditions of a kind of tepor difference, wherein the entrance and exit of secondary side fluid EGR is connected by a connecting line, and flow controller is provided between the first entrance of the entrance and tested heat exchanger, one first temperature sensor is provided between the outlet of flow controller and the first entrance of tested heat exchanger, second temperature sensor is provided between the outlet of secondary side fluid EGR and the first outlet of tested heat exchanger, first flowmeter is located at the first entrance or first outlet of tested heat exchanger；Primary side fluid supply apparatus is connected with secondary side fluid EGR, and its exit is provided with three-temperature sensor, entrance or outlet of the second flowmeter located at primary side fluid supply apparatus.The present invention uses thermally equilibrated test philosophy, can obtain the heat exchange amount of tested heat exchanger indirectly by the primary side fluid supply apparatus set up, therefore significantly improve the heat exchange amount measuring accuracy of tested heat exchanger.
Description
Technical field
The present invention relates to heat exchanger measuring technology, particularly belong to measure heat exchanger heat exchange amount under the conditions of a kind of tepor difference is
System and method.
Background technology
In heat exchanger industry, in order to detect the performance of heat exchanger, it usually needs using a heat exchanger performance test dress
Put, the test philosophy of the device is essentially enthalpy potential method, i.e., is counted by the mass flow and inlet and outlet enthalpy difference of one side liquid of measurement
Calculate the heat exchange amount of the heat exchanger.When fluid is monophasic fluid, such as water, it is possible to counted by measuring the out temperature of water
Calculate the enthalpy of water.Although this measuring method is simply easily achieved, but the shortcomings that certain be present, i.e. the measurement of heat exchange amount is smart
Degree influenceed by fluid inlet and outlet enthalpy difference or the temperature difference it is bigger, when the inlet and outlet enthalpy difference or the temperature difference of fluid are smaller, the survey of this method
It is bigger to measure error, is illustrated as an example using fluid as water below.
It is assumed that the uncertainty of measurement of mass flow is 0.1% (k=3), the measurement accuracy of temperature is 0.1 DEG C (k=2),
Ignore the influence of leakage heat.
Condition 1：It is assumed that the mass flow of water is 1kg/s, inlet temperature during inflow heat exchanger is 20 DEG C, from heat exchanger stream
Outlet temperature when going out is 30 DEG C, and the specific heat at constant pressure of 25 DEG C of water is 4.1816kJ/kg DEG C, then heat exchange amount is Q=1 × (30-20)
× 4.1816=41.816kW.The uncertainty of measurement of condition 1 is 0.592kW (k=2), referring to table one, uncertainty of measurement
Calculate reference《Use evaluation of uncertainty in measurement》, the 3rd edition, page 246, China Measuring Press, 2009.
Condition 2：It is assumed that the mass flow of water is 10kg/s, inlet temperature during inflow heat exchanger is 20 DEG C, from heat exchanger
Outlet temperature during outflow is 21 DEG C, and the specific heat at constant pressure of 20.5 DEG C of water is 4.1840kJ/kg DEG C, then heat exchange amount be Q=10 ×
(21-20) × 4.1840=41.840kW.The uncertainty of measurement of condition 2 is 5.91kW (k=2), referring to table two.
Although from both the above situation can be seen that two kinds under the conditions of heat exchange amount it is identical, the measurement accuracy of heat exchange amount
But differ widely.In the case of the fluid inlet and outlet temperature difference small (being less than or equal to 5 DEG C), the measurement accuracy of heat exchange amount how is improved
Important subject always in industry.Wherein, the most frequently used method is exactly the temperature sensor using higher precision, such as
The measurement accuracy of temperature sensor is brought up into 0.01 DEG C (k=2), if using this temperature sensor in condition 2, then
The uncertainty of measurement of condition 2 is just 0.592kW (K=2), such as table three.
However, above-mentioned result of calculation is theoretical precision, there is problems in engineering practice：
1) costly, and precision more high price is more expensive for sensor price, and should not be measured at the scene, and this is straight
Connect the popularization that have impact on test method；
2) the leakage heat of sensor is inevitably present in test process, and the problem of fluid temperature (F.T.) field uniformity,
Even with the temperature sensor that measurement accuracy is 0.01 DEG C, the temperature uncertainty actually measured can also be higher than foregoing theoretical meter
Temperature uncertainty in calculation, therefore in order to reduce the influence of Lou heat and temperature homogeneity, for the whole test system of heat exchanger
It is very high that system builds difficulty；
3) when the inlet and outlet temperature difference of fluid further reduces, if the temperature difference is at 0.1 DEG C~1 DEG C, at present also again without preferably
Solution method.
The content of the invention
The technical problem to be solved in the present invention is to provide under the conditions of a kind of tepor difference measure heat exchanger heat exchange amount system and
Method, the heat exchange amount measurement accuracy of heat exchanger can be improved in the case where the heat exchanger inlet and outlet temperature difference is small.
In order to solve the above technical problems, the system of heat exchanger heat exchange amount is measured under the conditions of tepor difference provided by the invention, bag
Include tested heat exchanger, secondary side fluid EGR and primary side fluid supply apparatus；
The tested heat exchanger includes first entrance, first outlet, second entrance and second outlet, wherein first entrance and
First outlet is connected with the secondary side fluid EGR, and second entrance and second outlet are flowed into and flowed by another heat exchanging fluid
Go out；
There is the secondary side fluid EGR flow controller, entrance A and outlet B, wherein entrance A and outlet B to lead to
Cross a connecting line to be connected, the flow controller makes the fluid flow constant of the tested heat exchanger first entrance of inflow, institute
The first entrance for stating tested heat exchanger is provided with one first temperature sensor, is tested between the first outlet of heat exchanger provided with one second
Temperature sensor, a first flowmeter are located at the first entrance of tested heat exchanger or the first outlet of tested heat exchanger；
The primary side fluid supply apparatus connects with secondary side fluid EGR, and exit is provided with one the 3rd temperature
Sensor, a second flowmeter are located at the porch or exit of primary side fluid supply apparatus, the side liquid supply
Device provides the fluid of steady temperature, and the fluid flow provided by changing primary side fluid supply apparatus makes the tested heat exchange of inflow
The fluid temperature (F.T.) of device first entrance is constant.
In said structure, the entrance A is close to the first entrance of tested heat exchanger, and outlet B is close to tested heat exchanger
First outlet, the flow controller are located between the first entrance of tested heat exchanger and entrance A, first temperature sensor
It is located between the outlet of flow controller and the first entrance of tested heat exchanger, second temperature sensor is located at tested heat exchanger
Between first outlet and outlet B.Or the entrance A, close to the first entrance of tested heat exchanger, outlet B is close to tested heat exchange
The first outlet of device, the flow controller are located between the first outlet of tested heat exchanger and outlet B, and first temperature passes
Sensor is located between the first entrance of tested heat exchanger and entrance A, second temperature sensor be located at the entrance of flow controller with
Between the first outlet of tested heat exchanger, the porch of the primary side fluid supply apparatus is provided with one the 4th temperature sensor.
In said structure, the primary side fluid supply apparatus directly connects with secondary side fluid EGR, wherein
The outlet of primary side fluid supply apparatus is connected with the entrance A of secondary side fluid EGR, primary side fluid supply apparatus
Entrance is connected with the outlet B of secondary side fluid EGR, the fluid one flowed out from the outlet B of secondary side fluid EGR
Primary side fluid supply apparatus is diverted into, another part flows back to the entrance A of secondary side fluid EGR and a side liquid supplies
The first entrance of tested heat exchanger is provided after the fluid mixing provided to device by flow controller, and supplied from a side liquid
The fluid flow that secondary side fluid EGR is flowed into device supplies with flowing into a side liquid from secondary side fluid EGR
Fluid flow to device is identical；Or the primary side fluid supply apparatus directly connects with secondary side fluid EGR,
Wherein the outlet of primary side fluid supply apparatus is connected with the outlet B of secondary side fluid EGR, a side liquid supply dress
The entrance put is connected with the entrance A of secondary side fluid EGR, the fluid flowed out from the outlet B of secondary side fluid EGR
The rear portion that the fluid provided with primary side fluid supply apparatus mixes flows back to primary side fluid supply apparatus, and another part flows into
The entrance A of secondary side fluid EGR and the first entrance that tested heat exchanger is flowed into by flow controller, and flow back to once
The fluid flow of effluent body feeding is identical with the fluid flow that primary side fluid supply apparatus provides.
Or in said structure, the primary side fluid supply apparatus is followed by an Intermediate Heat Exchanger with secondary side fluid
Loop device connects, and the wherein outlet of primary side fluid supply apparatus connects with the first entrance of Intermediate Heat Exchanger, a side liquid
The entrance of feedway connects with the first outlet of Intermediate Heat Exchanger, the outlet B and intermediate heat transfer of secondary side fluid EGR
The second entrance connection of device, the entrance A of secondary side fluid EGR connects with the second outlet of Intermediate Heat Exchanger, it is described once
The porch of effluent body feeding is provided with one the 4th temperature sensor.
Further, it is provided with a first pressure between the outlet of the flow controller and the first entrance of tested heat exchanger
Sensor, a second pressure is provided between the outlet of secondary side fluid EGR and the first outlet of tested heat exchanger and is sensed
Device.
Further, the porch of the primary side fluid supply apparatus is provided with one the 4th temperature sensor.
Wherein, the flow controller is water pump or water pump and regulating valve.
Wherein, the primary side fluid supply apparatus includes pump, flow control valve, heating cooler.
The present invention also provides what is realized using the system that heat exchanger heat exchange amount measurement accuracy is improved under the conditions of above-mentioned tepor difference
Method, wherein：
First temperature sensor monitors of secondary side fluid EGR flow into the fluid temperature of tested heat exchanger first entrance
Degree, from the fluid temperature (F.T.) of tested heat exchanger first outlet outflow, first flowmeter, which monitors, flows into quilt for second temperature sensor monitoring
Survey heat exchanger first entrance or the fluid flow from the outflow of tested heat exchanger first outlet；The of primary side fluid supply apparatus
From the fluid temperature (F.T.) of primary side fluid supply apparatus outflow, second flowmeter, which monitors, flows into an effluent for three-temperature sensor monitoring
Body feeding or the fluid flow from the outflow of primary side fluid supply apparatus；
The fluid temperature (F.T.) for flowing into tested heat exchanger first entrance remains at same test temperature, secondary side fluid circulation
The fluid flow that the flow controller control of device flows into tested heat exchanger first entrance is maintained at same test flow, primary side
The fluid temperature (F.T.) that fluid supply apparatus provides is maintained at same supplying temperature；
Whole system is thermally shielded insulation (control environment temperature is close to the fluid temperature (F.T.) in tested heat exchanger, and
Make leakage heat be less than tested heat exchanger heat exchange amount 1%), when system stable operation is in thermal equilibrium state, then
Q=F1*C1* (T2-T1)=F2*C2* (T2-T3)-W+Qleak+q≈F2*C2*(T2-T3)-W+q
W=(M*H1*S)/(367.7*E)
Q=(M*H2*S)/367.7
Wherein, Q is the heat exchange amount of tested heat exchanger, and F1 is the quality stream for the fluid that tested heat exchanger first entrance flows into
Amount, C1 are the avergae specific heat for the fluid that tested heat exchanger first entrance flows into, and T1 is the stream that tested heat exchanger first entrance flows into
The temperature of body, T2 are the temperature of the fluid of tested heat exchanger first outlet outflow, and F2 is what primary side fluid supply apparatus provided
The mass flow of fluid, C2 are the avergae specific heat of the fluid of primary side fluid supply apparatus outflow, and T3 is that a side liquid supplies
Device outflow fluid temperature, W be secondary side fluid EGR in flow controller power, QleakLeaked for pipeline
Heat, q are the heat energy that fluid converts by friction in heat exchanger, and M is the volume flow for the fluid that tested heat exchanger first entrance flows into
Amount, H1 is lift；S is the specific density for the fluid that tested heat exchanger first entrance flows into；E is the efficiency of pump in flow controller；
H2 is the design resistance of tested heat exchanger.
In the above-mentioned methods, when primary side fluid supply apparatus directly connects with secondary side fluid EGR, once
The outlet of effluent body feeding is connected with the entrance A of secondary side fluid EGR, the entrance of primary side fluid supply apparatus
It is connected with the outlet B of secondary side fluid EGR, the fluid part stream flowed out from the outlet B of secondary side fluid EGR
Enter primary side fluid supply apparatus, another part flows back to the entrance A of secondary side fluid EGR, flows into a side liquid supply
The fluid flow of device is identical with the fluid flow flowed out from primary side fluid supply apparatus；Control primary side fluid supply apparatus
The mixing of fluid of the fluid of offer with flowing back to secondary side fluid EGR entrance A from secondary side fluid EGR outlet B
The fluid temperature (F.T.) that ratio flows into tested heat exchanger first entrance remains at same test temperature；
When primary side fluid supply apparatus is connected by an Intermediate Heat Exchanger with secondary side fluid EGR, primary side
The outlet of fluid supply apparatus is connected with the first entrance of Intermediate Heat Exchanger, and the entrance of primary side fluid supply apparatus and centre are changed
The first outlet connection of hot device, the outlet of secondary side fluid EGR connect with the second entrance of Intermediate Heat Exchanger, secondary side
The entrance of fluid circulating device connects with the second outlet of Intermediate Heat Exchanger.
Preferably, the 4th temperature sensor monitors flow into primary side fluid supply apparatus from secondary side fluid EGR
Fluid temperature (F.T.), then
Q=F1*C1* (T2-T1)=F2*C2* (T4-T3)-W+Qleak+q
Wherein, T4 is the temperature for the fluid that primary side fluid supply apparatus flows into.
In the above-mentioned methods, tested heat exchanger is subjected to insulation (leakage heat is less than the 1% of tested heat exchanger heat exchange amount),
And make between the second entrance and second outlet of tested heat exchanger without heat exchanging fluid, when system stable operation,
Q=q
W-Qleak≈ W=F2*C2* (T2-T3)
Calculated according to F2, T2, T3 value, standard uncertainty, probability distribution, sensitivity coefficient and partial uncertainty
Into secondary side fluid EGR in flow controller the power of pump uncertainty of measurement, wherein T2=q/F1/C1+T1；
It is calculated according to F1, H2 value, standard uncertainty, probability distribution, sensitivity coefficient and partial uncertainty
The uncertainty of measurement for the heat energy that fluid converts by friction in tested heat exchanger；
According to F2, T1, T2, W-Qleak, q value, standard uncertainty, probability distribution, sensitivity coefficient, partial uncertainty
The uncertainty of measurement of the heat exchange amount of tested heat exchanger is calculated.
Preferably, the flow controller is water pump, and water is measured by the torque rotational speed meter in water pump input shaft
The shaft power of pump.
The present invention is additionally arranged primary side fluid supply apparatus, using thermally equilibrated test philosophy, by controlling an effluent
The fluid temperature (F.T.) that the fluid flow and temperature of body feeding make to flow into tested heat exchanger in test process every time is maintained at same
Test temperature, although the inlet and outlet temperature difference of so tested heat exchanger is small, it is tested and changes when test system is in stable operation
The heat exchange amount of hot device can be obtained by the heat exchange amount of primary side fluid supply apparatus indirectly, therefore can significantly improve tested change
The heat exchange amount measuring accuracy of hot device.
Brief description of the drawings
Fig. 1 is the structural representation of the first embodiment of the present invention；
Fig. 2 is the structural representation of the second embodiment of the present invention；
Fig. 3 is the composition schematic diagram of primary side fluid supply apparatus in the present invention.
Wherein description of reference numerals is as follows：
1 is tested heat exchanger；2 be primary side fluid supply apparatus；21 be pump；22 be flow control valve；23 be electrical heating
Device；24 be cooling unit；3 be Intermediate Heat Exchanger.
Embodiment
The present invention is further detailed explanation with embodiment below in conjunction with the accompanying drawings.
The first embodiment of the system of heat exchanger heat exchange amount is measured under the conditions of tepor difference provided by the invention, as shown in figure 1,
Including being tested heat exchanger 1, secondary side fluid EGR and primary side fluid supply apparatus 2；
The tested heat exchanger 1 includes first entrance, first outlet, second entrance and second outlet, wherein first entrance
Be connected with first outlet with the secondary side fluid EGR, second entrance and second outlet then flowed into for a heat exchanging fluid and
Outflow；
The entrance A of the secondary side fluid EGR is connected with outlet B by a connecting line, and entrance A and quilt
Survey between the first entrance of heat exchanger 1 and be provided with a flow controller, the of the outlet of the flow controller and tested heat exchanger 1
Be provided with one first temperature sensor and a first pressure sensor between one entrance, the outlet B of secondary side fluid EGR with
A second temperature sensor and a second pressure sensor, a first flowmeter are provided between the first outlet of tested heat exchanger 1
Located at flow controller outlet the first entrance of tested heat exchanger 1 between or tested heat exchanger 1 first outlet and two
Between the outlet B of secondary side liquid EGR, for testing the fluid stream between the tested first entrance of heat exchanger 1 and first outlet
Amount, in the present embodiment, before first flowmeter is located at the first entrance of tested heat exchanger 1；
The primary side fluid supply apparatus 2 directly connects with secondary side fluid EGR, wherein a side liquid supplies
Outlet to device 2 is connected with the entrance of secondary side fluid EGR, the entrance and secondary side of primary side fluid supply apparatus
The outlet of fluid circulating device is connected, and the exit of primary side fluid supply apparatus 2 is provided with a three-temperature sensor and one the
Two flowmeters, the porch of primary side fluid supply apparatus 2 are provided with one the 4th temperature sensor.
Wherein, primary side fluid supply apparatus is flowed into from a fluid part for secondary side fluid EGR outlet B outflows
2, the fluid that another part flows back to secondary side fluid EGR entrance A with primary side fluid supply apparatus 2 provides leads to after mixing
Excessively stream amount controller flows into the first entrance of tested heat exchanger 1, and the fluid flow that provides of primary side fluid supply apparatus 2 with from
The fluid flow that secondary side fluid EGR flows into primary side fluid supply apparatus 2 is identical, therefore second flowmeter can also be set
In the porch of primary side fluid supply apparatus 2.
Meanwhile in the case where not considering leakage heat and flowage friction influence, flowed from the outlet B of secondary side fluid EGR
Enter the fluid temperature (F.T.) basic one that the fluid temperature (F.T.) of primary side fluid supply apparatus 2 flows out with the first outlet from tested heat exchanger 1
Cause, therefore the 4th temperature sensor can be omitted.
In the present embodiment, flow controller is pump, and tested heat exchange can be controlled by the rotating speed (or frequency) for changing pump
The fluid flow of device 1.
In said system, the first temperature sensor monitors of secondary side fluid EGR flow into tested heat exchanger first
The fluid temperature (F.T.) of entrance, the fluid temperature (F.T.) that second temperature sensor monitoring is flowed out from tested heat exchanger first outlet, first flow
Meter monitoring flows into tested heat exchanger first entrance or the fluid flow from the outflow of tested heat exchanger first outlet；Side liquid
The fluid temperature (F.T.) that the three-temperature sensor monitoring of feedway 2 is flowed out from primary side fluid supply apparatus 2, the 4th TEMP
Device monitoring flows into the fluid temperature (F.T.) T4 of primary side fluid supply apparatus 2, second flowmeter monitoring from secondary side fluid EGR
Flow into primary side fluid supply apparatus or the fluid flow from the outflow of primary side fluid supply apparatus.
When the fluid that secondary side fluid EGR provides is heated in tested heat exchanger 1, the fluid temperature of A points offer
Degree must be less than the fluid temperature (F.T.) of the tested first entrance of heat exchanger 1；When fluid is cooled in tested heat exchanger 1, what A points provided
Water temperature must be higher than the fluid temperature (F.T.) of the tested first entrance of heat exchanger 1.
Primary side fluid supply apparatus 2 is flowed into from a fluid part for secondary side fluid EGR outlet B outflows, it is another
Part flows into again after flowing back to secondary side fluid EGR entrance A and being mixed with the fluid flowed out from primary side fluid supply apparatus 2
In tested heat exchanger 1, the fluid temperature (F.T.) flowed out from primary side fluid supply apparatus 2 is maintained at same supplying temperature, flows into once
The fluid flow of effluent body feeding 2 is identical with the fluid flow flowed out from primary side fluid supply apparatus 2；Control primary side
The fluid that fluid supply apparatus 2 provides from secondary side fluid EGR outlet B with flowing back to secondary side fluid EGR entrance A
The mixed proportion fluid temperature (F.T.) that flows into the tested first entrance of heat exchanger 1 of fluid remain at same test temperature；
Insulation is thermally shielded to whole system, when system stable operation is in thermal equilibrium state, then
Q=F1*C1* (T2-T1)=F2*C2* (T4-T3)-W+Qleak+q≈F2*C2*(T2-T3)-W+Qleak+q≈F2*
C2*(T2-T3)-W+q
W=(M*H1*S)/(367.7*E)
Q=(M*H2*S)/367.7
Wherein, Q is the heat exchange amount of tested heat exchanger, and F1 is the quality stream for the fluid that tested heat exchanger first entrance flows into
Amount, C1 are the avergae specific heat for the fluid that tested heat exchanger first entrance flows into, and T1 is the stream that tested heat exchanger first entrance flows into
The temperature of body, T2 are the temperature of the fluid of tested heat exchanger first outlet outflow, and F2 is what primary side fluid supply apparatus provided
The mass flow of fluid, C2 are the avergae specific heat of the fluid of primary side fluid supply apparatus outflow, and T3 is that a side liquid supplies
Device outflow fluid temperature, W be secondary side fluid EGR in flow controller power, QleakLeaked for pipeline
Heat, q are the heat energy that fluid converts by friction in heat exchanger, and M is the volume flow for the fluid that tested heat exchanger first entrance flows into
Amount, H1 is lift；S is the specific density for the fluid that tested heat exchanger first entrance flows into；E is the efficiency of pump in flow controller；
H2 is the design resistance of tested heat exchanger.
Tested heat exchanger is subjected to insulation, and makes to be tested between the second entrance and second outlet of heat exchanger without heat exchange
Fluid, during system stable operation, Q=q can be approximately considered, then can measure W-Qleak≈ W=F2*C2* (T2-T3), according to F2,
T2, T3 value, standard uncertainty, probability distribution, sensitivity coefficient and partial uncertainty are calculated secondary side fluid and followed
In loop device in flow controller the power of pump uncertainty of measurement, wherein T2=q/F1/C1+T1；
It is calculated according to F1, H2 value, standard uncertainty, probability distribution, sensitivity coefficient and partial uncertainty
The uncertainty of measurement for the heat energy that fluid converts by friction in tested heat exchanger；
According to F2, T1, T2, W-Qleak, q value, standard uncertainty, probability distribution, sensitivity coefficient, partial uncertainty
The uncertainty of measurement of the heat exchange amount of tested heat exchanger is calculated.
Below, then by taking condition 2 as an example, analyzed, wherein it is assumed that the mass flow of water is 10kg/s, during inflow heat exchanger
Inlet temperature be 20 DEG C, outlet temperature when flow out from heat exchanger is 21 DEG C, and the specific heat at constant pressure of 20.5 DEG C of water is 4.1840kJ/
Kg DEG C, then heat exchange amount is Q=10 × (21-20) × 4.1840=41.840kW.
First, being reduced to Qleak by provision for thermal insulation can ignore (for example：Package unit is placed on to 20 DEG C of environment
In).
The work(that pump convection body is done is W=(M*H*S)/(367.7*E), wherein, W is that shaft power kW, M are volume flow m3/
H, H are that lift m, S are specific density (water@20 DEG C=1.0), and E is pump efficiency.The heat energy that fluid should rub and convert in pipeline is
Q=(M*H*S)/(367.7) kW.
The design resistance of heat exchanger is generally less than 5 meters, and the resistance of ducting is generally smaller than 5 meters.The efficiency one of one centrifugal pump
As be higher than 50%.Thus, under condition 2, the shaft power W of pump is：
(10*3600/998.06) * 10*0.998/ (367.7*0.5)=1.958kW.
By measuring heat exchanger inlet and outlet pressure difference, fluid can be estimated and flow through heat exchanger, the interior energy caused by frictional heat
Changing q is：
(10*3600/998.06) * 5*0.998/ (367.7)=0.490kW.
The uncertainty of measurement that q can be obtained by table four is 0.0979kW (K=2).
Because the shaft power of pump is an estimate, therefore measured firstly the need of to it.Therefore, first tested heat exchanger
1 carries out insulation, and separates the flow of fluid of the tested opposite side of heat exchanger 1.Control flows into the fluid temperature (F.T.) of A points (i.e. once
The fluid temperature (F.T.) that effluent body feeding 2 flows out) it is 10 DEG C, the temperature of inflow heat exchanger is 20 DEG C, flows through the flow of heat exchanger
For 10kg/s, when reaching stable, then have
0=F2*C (T4-T3)-W+Qleak
W-Qleak=F2*C (T4-T3)
As example, then make
W-Qleak=1.958kW, C=4.1888kJ/kg DEG C,
T1=20 DEG C, T2=0.490/10/4.1844+20=20.012 DEG C, T3=10 DEG C, T4 ≈ T2=20.012 DEG C,
F2=1.958/4.1888/ (20.012-10)=0.0467kg/s
The uncertainty of measurement that shaft power can be obtained by table five is 0.0277kW (K=2).
Then, experiment is proceeded by.The fluid temperature (F.T.) that control flows into A points is still 10 DEG C, and the temperature of inflow heat exchanger is 20
DEG C, the flow for flowing through heat exchanger is 10kg/s, when reaching stable, is then had
Q=F2*C (T4-T3)-W+Qleak+q
As example, then make
W-Qleak=1.958kW
Q=0.490kW
T1=20 DEG C, T2=21 DEG C, T3=10 DEG C, T4 ≈ T2=21 DEG C,
F2=(1.958+41.840)/4.1883/ (21-10)=0.951kg/s
The uncertainty of measurement that heat exchange amount can be obtained by table six is 0.573kW (k=2).
It can thus be seen that although the precision of temperature sensor does not improve, pass through primary side fluid supply apparatus
Measuring accuracy of heat exchanger inlet and outlet when small smaller can be significantly improved.
In the first embodiment, the position that flow controller can also be changed according to being actually needed, if entrance A is close to tested
Flow controller is located at the of tested heat exchanger by the first entrance of heat exchanger, outlet B close to the first outlet of tested heat exchanger
Between one outlet and outlet B, the first temperature sensor is located between the first entrance of tested heat exchanger and entrance A, second temperature
Sensor is located between the entrance of flow controller and the first outlet of tested heat exchanger, at this moment needs to supply in a side liquid
The porch of device is provided with one the 4th temperature sensor.
In the second embodiment of the present invention, primary side fluid supply apparatus passes through an Intermediate Heat Exchanger 3 and secondary side fluid
EGR connects, and the wherein outlet of primary side fluid supply apparatus 2 connects with the first entrance of Intermediate Heat Exchanger 3, primary side
The entrance of fluid supply apparatus 2 connects with the first outlet of Intermediate Heat Exchanger 3, outlet and the centre of secondary side fluid EGR
The second entrance connection of heat exchanger 3, the entrance of secondary side fluid EGR connect with the second outlet of Intermediate Heat Exchanger 3.It is logical
The fluid temperature (F.T.) that crossing the fluid of the outflow of control primary side fluid supply apparatus 2 makes to flow into tested heat exchanger 1 every time remains at
Same temperature.
The embodiment is applied to the fluid temperature (F.T.) of the first entrance of tested heat exchanger 1 close to the situation of transformation temperature, such as tested
The water temperature of the first entrance of heat exchanger 1 is 1 DEG C, and now primary side fluid supply apparatus can not flow into A points using -10 DEG C of water.
Therefore, physical property and the point fluid away from phase transformation known to being used using Intermediate Heat Exchanger and in the opposite side of Intermediate Heat Exchanger, for example
Glycol water, the heat exchange amount by measuring glycol water can measure the heat exchange amount of tested heat exchanger indirectly.
Certainly, tested heat exchanger can be used for realizing refrigerating function, it is assumed that the mass flow of water is 10kg/s, and water enters
Mouth temperature T1 is 21 DEG C, and outlet temperature T2 is 20 DEG C, and the specific heat at constant pressure of 20.5 DEG C of water is 4.1840kJ/kg DEG C, then heat exchange amount is Q
=10 × (21-20) × 4.1840=41.840kW, now, T3=30 DEG C is can use, equally can also obtain and measure high-precision change
Heat result.
In the above two embodiments, it was found from analysis of measurement errors, q is fallen within a small amount, when heat exchanger resistance very little,
This part can directly be ignored.
For the shaft power of pump, torque rotational speed meter can be installed on the input shaft of pump, thus can be with direct measurement pump
Shaft power.And controlled for the flow of heat exchanger side, can not be by changing revolution speed, but changed by a regulating valve
Flow.
Above-mentioned first flowmeter and second flowmeter can be mass flowmenter or electromagnetic flowmeter.
In the present invention, primary side fluid supply apparatus can include pump, flow control valve, heating cooler, such as Fig. 3 institutes
Show, heating cooler is common electric heater and cools down unit, and the composition is to those skilled in the art can be with
Easily build, be not added with being described in detail herein.
The present invention is described in detail above by specific embodiment, the embodiment is only the preferable of the present invention
Embodiment, it not limits the invention.Without departing from the principles of the present invention, those skilled in the art makes
Equivalent replacement and improvement, be regarded as in the technology category protected of the present invention.
Claims (15)
1. the system of heat exchanger heat exchange amount measurement accuracy is improved under the conditions of a kind of tepor difference, it is characterised in that including tested heat exchange
Device, secondary side fluid EGR and primary side fluid supply apparatus；
The tested heat exchanger includes first entrance, first outlet, second entrance and second outlet, wherein first entrance and first
Outlet is connected with the secondary side fluid EGR, and second entrance and second outlet are flowed in and out by another heat exchanging fluid,
The first entrance of the tested heat exchanger is provided with one first temperature sensor, and the first outlet for being tested heat exchanger is provided with one second temperature
Sensor is spent, a first flowmeter is located at the first entrance of tested heat exchanger or the first outlet of tested heat exchanger；
There is the secondary side fluid EGR flow controller, entrance A and outlet B, wherein entrance A and outlet B to pass through one
Connecting line is connected, and the flow controller makes the fluid flow constant of the tested heat exchanger first entrance of inflow；
The primary side fluid supply apparatus connects with secondary side fluid EGR, and exit is provided with one the 3rd TEMP
Device, a second flowmeter are located at the porch or exit of primary side fluid supply apparatus, the primary side fluid supply apparatus
The fluid of steady temperature is provided, by controlling the fluid flow that primary side fluid supply apparatus provides inflow is tested heat exchanger the
The fluid temperature (F.T.) of one entrance is constant.
2. improving the system of heat exchanger heat exchange amount measurement accuracy under the conditions of tepor difference according to claim 1, its feature exists
In the entrance A is close to the first entrance of tested heat exchanger, and outlet B is close to the first outlet of tested heat exchanger, the flow control
Device processed is located between the first entrance of tested heat exchanger and entrance A, and first temperature sensor is located at going out for flow controller
Mouthful between the first entrance of tested heat exchanger, second temperature sensor be located at the first outlet of tested heat exchanger and outlet B it
Between.
3. improving the system of heat exchanger heat exchange amount measurement accuracy under the conditions of tepor difference according to claim 1, its feature exists
In the entrance A is close to the first entrance of tested heat exchanger, and outlet B is close to the first outlet of tested heat exchanger, the flow control
Device processed is located between the first outlet of tested heat exchanger and outlet B, and first temperature sensor is located at the of tested heat exchanger
Between one entrance and entrance A, second temperature sensor be located at the entrance of flow controller and tested heat exchanger first outlet it
Between, the porch of the primary side fluid supply apparatus is provided with one the 4th temperature sensor.
4. improving the system of heat exchanger heat exchange amount measurement accuracy under the conditions of tepor difference according to claim 1, its feature exists
In the primary side fluid supply apparatus directly connects with secondary side fluid EGR, wherein primary side fluid supply apparatus
Outlet be connected with the entrance A of secondary side fluid EGR, entrance and the secondary side fluid of primary side fluid supply apparatus are followed
The outlet B of loop device is connected, and the fluid part flowed out from the outlet B of secondary side fluid EGR flows into a side liquid
Feedway, another part flow back to the fluid that the entrance A of secondary side fluid EGR provides with primary side fluid supply apparatus
The first entrance of tested heat exchanger is flowed into after mixing by flow controller, and secondary side is flowed into from primary side fluid supply apparatus
The fluid flow of fluid circulating device and the fluid flow that primary side fluid supply apparatus is flowed into from secondary side fluid EGR
It is identical.
5. improving the system of heat exchanger heat exchange amount measurement accuracy under the conditions of tepor difference according to claim 1, its feature exists
In the primary side fluid supply apparatus directly connects with secondary side fluid EGR, wherein primary side fluid supply apparatus
Outlet be connected with the outlet B of secondary side fluid EGR, entrance and the secondary side fluid of primary side fluid supply apparatus are followed
The entrance A of loop device is connected, and the fluid flowed out from the outlet B of secondary side fluid EGR carries with primary side fluid supply apparatus
The fluid mixing rear portion of confession flows back to primary side fluid supply apparatus, and another part flows into entering for secondary side fluid EGR
Mouth A and the first entrance that tested heat exchanger is flowed into by flow controller, and flow back to the fluid stream of primary side fluid supply apparatus
Measure identical with the fluid flow that primary side fluid supply apparatus provides.
6. improving the system of heat exchanger heat exchange amount measurement accuracy under the conditions of tepor difference according to claim 1, its feature exists
In the primary side fluid supply apparatus is connected by an Intermediate Heat Exchanger with secondary side fluid EGR, wherein primary side
The outlet of fluid supply apparatus is connected with the first entrance of Intermediate Heat Exchanger, and the entrance of primary side fluid supply apparatus and centre are changed
The first outlet connection of hot device, the outlet B of secondary side fluid EGR connect with the second entrance of Intermediate Heat Exchanger, secondary side
The entrance A of fluid circulating device connects with the second outlet of Intermediate Heat Exchanger, the porch of the primary side fluid supply apparatus
Provided with one the 4th temperature sensor.
7. heat exchanger heat exchange amount measurement accuracy is improved under the conditions of tepor difference as claimed in any of claims 1 to 5
System, it is characterised in that be provided with a first pressure between the outlet of the flow controller and the first entrance of tested heat exchanger
Sensor, a second pressure is provided between the outlet of secondary side fluid EGR and the first outlet of tested heat exchanger and is sensed
Device.
8. the system of heat exchanger heat exchange amount measurement accuracy, its feature are improved under the conditions of the tepor difference according to claim 4 or 5
It is, the porch of the primary side fluid supply apparatus is provided with one the 4th temperature sensor.
9. heat exchanger heat exchange amount measurement accuracy is improved under the conditions of tepor difference as claimed in any of claims 1 to 6
System, it is characterised in that the flow controller is water pump or water pump and regulating valve.
10. heat exchanger heat exchange amount measurement accuracy is improved under the conditions of tepor difference as claimed in any of claims 1 to 6
System, it is characterised in that the primary side fluid supply apparatus includes pump, flow control valve, heating cooler.
It is 11. a kind of real using the system that heat exchanger heat exchange amount measurement accuracy is improved under the conditions of tepor difference as claimed in claim 1
Existing method, it is characterised in that
First temperature sensor monitors of secondary side fluid EGR flow into the fluid temperature (F.T.) of tested heat exchanger first entrance, the
The fluid temperature (F.T.) that two temperature sensor monitors flow out from tested heat exchanger first outlet, first flowmeter monitoring flow into tested heat exchange
Device first entrance or the fluid flow from the outflow of tested heat exchanger first outlet；3rd temperature of primary side fluid supply apparatus
The fluid temperature (F.T.) that Sensor monitoring flows out from primary side fluid supply apparatus, second flowmeter monitoring flow into a side liquid supply
Device or the fluid flow from the outflow of primary side fluid supply apparatus；
The fluid temperature (F.T.) for flowing into tested heat exchanger first entrance remains at same test temperature, secondary side fluid EGR
Flow controller control flow into the fluid flow of tested heat exchanger first entrance and be maintained at same test flow, a side liquid
The fluid temperature (F.T.) that feedway provides is maintained at same supplying temperature；
Insulation is thermally shielded to whole system, when system stable operation is in thermal equilibrium state, then
Q=F1*C1* (T2-T1)=F2*C2* (T2-T3)-W+Qleak+q≈F2*C2*(T2-T3)-W+q
W=(M*H1*S)/(367.7*E)
Q=(M*H2*S)/367.7
Wherein, Q is the heat exchange amount of tested heat exchanger, and F1 is the mass flow for the fluid that tested heat exchanger first entrance flows into, C1
To be tested the avergae specific heat for the fluid that heat exchanger first entrance flows into, T1 is the temperature for the fluid that tested heat exchanger first entrance flows into
Degree, T2 are the temperature of the fluid of tested heat exchanger first outlet outflow, and F2 is the fluid that primary side fluid supply apparatus provides
Mass flow, C2 are the avergae specific heat of the fluid of primary side fluid supply apparatus outflow, and T3 is primary side fluid supply apparatus stream
The temperature of the fluid gone out, W be secondary side fluid EGR in flow controller power, QleakHeat is leaked for pipeline, q is to change
The heat energy that fluid converts by friction in hot device, M are the volume flow for the fluid that tested heat exchanger first entrance flows into, and H1 is to raise
Journey；S is the specific density for the fluid that tested heat exchanger first entrance flows into；E is the efficiency of pump in flow controller；H2 changes to be tested
The design resistance of hot device.
12. according to the method for claim 11, it is characterised in that
When primary side fluid supply apparatus directly connects with secondary side fluid EGR, primary side fluid supply apparatus goes out
Mouth is connected with the entrance A of secondary side fluid EGR, and entrance and the secondary side fluid circulation of primary side fluid supply apparatus fill
The outlet B put is connected, and the fluid part flowed out from the outlet B of secondary side fluid EGR flows into a side liquid supply dress
Put, another part flows back to the entrance A of secondary side fluid EGR, flow into the fluid flow of primary side fluid supply apparatus with from
The fluid flow of primary side fluid supply apparatus outflow is identical；Control the fluid that primary side fluid supply apparatus provides with from two
The mixed proportion for the fluid that secondary side liquid EGR outlet B flows back to secondary side fluid EGR entrance A makes tested heat exchanger
The fluid temperature (F.T.) that first entrance flows into remains at same test temperature；
When primary side fluid supply apparatus is connected by an Intermediate Heat Exchanger with secondary side fluid EGR, a side liquid
The outlet of feedway connects with the first entrance of Intermediate Heat Exchanger, the entrance and Intermediate Heat Exchanger of primary side fluid supply apparatus
First outlet connection, the outlet of secondary side fluid EGR connects with the second entrance of Intermediate Heat Exchanger, secondary side fluid
The entrance of EGR connects with the second outlet of Intermediate Heat Exchanger.
13. according to the method for claim 11, it is characterised in that the 4th temperature sensor monitors circulate from secondary side fluid
Device flows into the fluid temperature (F.T.) of primary side fluid supply apparatus, then
Q=F1*C1* (T2-T1)=F2*C2* (T4-T3)-W+Qleak+q
Wherein, T4 is the temperature for the fluid that primary side fluid supply apparatus flows into.
14. according to the method for claim 11, it is characterised in that
Tested heat exchanger is subjected to insulation, and makes to flow without heat exchange between the second entrance and second outlet of tested heat exchanger
Body, when system stable operation,
Q=q
W-Qleak≈ W=F2*C2* (T2-T3)
Two are calculated according to F2, T2, T3 value, standard uncertainty, probability distribution, sensitivity coefficient and partial uncertainty
In secondary side liquid EGR in flow controller the power of pump uncertainty of measurement, wherein T2=q/F1/C1+T1；
It is calculated according to F1, H2 value, standard uncertainty, probability distribution, sensitivity coefficient and partial uncertainty tested
The uncertainty of measurement for the heat energy that fluid converts by friction in heat exchanger；
According to F2, T1, T2, W-Qleak, q value, standard uncertainty, probability distribution, sensitivity coefficient, partial uncertainty calculate
Obtain the uncertainty of measurement of the heat exchange amount of tested heat exchanger.
15. according to the method for claim 11, it is characterised in that the flow controller is water pump, by installed in water
The shaft power of torque rotational speed meter measurement water pump on pump input shaft.
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| CN107238450A (en) * | 2017-06-05 | 2017-10-10 | 安徽万瑞冷电科技有限公司 | A kind of cryogenic fluid transfer pipeline leakage heat test device and method |
| CN113702081B (en) * | 2021-08-27 | 2024-03-29 | 欧伏电气股份有限公司 | Heat exchange core testing method, electronic equipment, system and storage medium |
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| US5902043A (en) * | 1994-11-07 | 1999-05-11 | British Gas Plc | Apparatus and method for measuring heat power consumed in or extracted from a region |
| CN101294857A (en) * | 2007-04-27 | 2008-10-29 | 西北工业大学 | Heat flow meter and measuring method thereof |
| CN201242503Y (en) * | 2008-08-13 | 2009-05-20 | 上海亚新建设工程总承包有限公司 | Portable device for testing heat exchange capability of buried tube heat exchanger |
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| US5902043A (en) * | 1994-11-07 | 1999-05-11 | British Gas Plc | Apparatus and method for measuring heat power consumed in or extracted from a region |
| CN101294857A (en) * | 2007-04-27 | 2008-10-29 | 西北工业大学 | Heat flow meter and measuring method thereof |
| CN201242503Y (en) * | 2008-08-13 | 2009-05-20 | 上海亚新建设工程总承包有限公司 | Portable device for testing heat exchange capability of buried tube heat exchanger |
| CN202119617U (en) * | 2011-05-13 | 2012-01-18 | 上海工程技术大学 | Heat exchange tester of surface water heat exchanger |
| CN204944707U (en) * | 2015-09-16 | 2016-01-06 | 上海佐竹冷热控制技术有限公司 | The system that heat interchanger heat exchange measures accuracy of measurement is improved under micro-temperature difference condition |
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