CN103105269A - Measuring method of air leakage rate of primary air of air pre-heater - Google Patents

Abstract

A measuring method of an air leakage rate of primary air of an air pre-heater comprises the steps of measuring primary air pressure, secondary air pressure, gas lateral pressure and an integral air leakage rate of the air pre-heater under n working conditions, obtaining a relational expression of the air leakage rate and pressure difference according to the measured values, obtaining air leakage rate of the primary air under the condition of air pre-heater entrance smoke by substituting the primary air pressure, the secondary air pressure, the gas lateral pressure and the integral air leakage rate under each working condition to the relational expression of the air leakage rate and the pressure difference, measuring air pre-heater entrance oxygen quantity, fuel coal quantity, primary air amount and analyzing elements of as received basis moisture, as received basis carbon, as received basis total sulfur, as received basis hydrogen, as received basis oxygen and as received basis nitrogen of coal used by the air pre-heater, forming theoretical air quantity and theoretical wet smoke quantity according to the element analysis, and calculating the air leakage rate of the primary air according to the air leakage rate of the primary air under the condition of air pre-heater entrance smoke, the air pre-heater entrance oxygen quantity, the fuel coal quantity, the primary air amount, the theoretical air quantity and the theoretical wet smoke quantity.

Description

Air preheater primary air leakage measuring method

Technical field

The invention relates to the air preheater technology, particularly about the air leak rate of air curtain measuring technique of air preheater, is about air preheater primary air leakage measuring method concretely.

Background technology

Fig. 1 is typical rotary regenerative air preheater, is comprised of columnar rotor and fixing cylindrical housing, cigarette air channel and gearing.All does not rotate in cylindrical housing and cigarette air channel, and inner cylindrical rotor rotates, in rotor regularly close-packed arrays heat transfer element (heating surface)-heat accumulation plate, heat accumulation plate is comprised of corrugated sheet and location-plate, is spaced to be placed in the lattice of storehouse.For two minutes storehouse air preheaters, the top of cylindrical housing and bottom were separated into flue gas Circulation Area, circulation of air district and seal area (zone of transition) three parts up and down accordingly; For three minutes storehouse air preheaters, the top of cylindrical housing and bottom are separated into flue gas Circulation Area, Secondary Air circulation of air district, seal area (zone of transition), wind circulation of air district, and seal area (zone of transition) five parts up and down accordingly, the flue gas Circulation Area is connected with flue, and the circulation of air district is connected with the air channel.Rotor drives slow circumvolve by motor by gearing, and (0.75～2.5rpm), heating surface alternately passes through flue gas and air duct.When heating surface forwarded the flue gas Circulation Area to, flue gas flow through heating surface from top to bottom, and heat is passed to the heating surface metal by flue gas, and was amassed by the metal poultry, and its temperature raises.When then heating surface forwarded the circulation of air district to, the heat that the heating surface metal just will be accumulated passed to the air that flows through from bottom to top, and temperature reduces.Circulation is gone down like this, in every one week of rotation of rotor, just completes a heat exchanging process.

In order to prevent leaking out, general rotary regenerative air preheater is equipped with the packoff of three directions, as shown in Figure 2, even but like this, still can not fully separate flue gas and air, when air side pressure during greater than fume side pressure, the air fume side of bleeding from the space that rotating part and fixed part divide.

Primary air leakage refers to that wind direction fume side of air preheater and Secondary Air side leakage air quantity account for the summation of primary air flow.Air leak rate of air curtain can be calculated by following formula:

Prior art is mainly directly to calculate primary air leakage by wind entrance air quantity of direct measurement and the method for outlet air quantity.Gaging hole position when directly measuring and condition be as shown in Figure 3: during measurement, with thermopair and dynamic pressure measurement element such as pitot tube, backing tube of demarcating etc., carry out the measurement of dynamic pressure, then calculate density and the speed of a wind of a wind feeder connection and exit, calculate the primary air flow at this place, calculate air leak rate of air curtain by following formula (1).

But following shortcoming is arranged during the measurement of above-mentioned primary air leakage:

1) exit one a time air temperature is up to more than 300 ℃, and pressure is greater than 10kPa, and easily security incident occurs the leakage due to a wind when measuring a wind outlet air quantity.

2) flue of a wind gateway is all irregular, lacks straight length, and the fluid-velocity survey error is large.

Summary of the invention

The invention provides a kind of air preheater primary air leakage measuring method, so that the accuracy of measuring primary air leakage to be provided, avoid danger and the error directly measured.

To achieve these goals, the invention provides a kind of air preheater primary air leakage measuring method, the method comprises: measure the primary air pressure of air preheater under n operating mode, Secondary Air pressure, fume side pressure and whole air leak rate of air curtain; With the primary air pressure of each operating mode in a described n operating mode, Secondary Air pressure, system of equations below fume side pressure and whole air leak rate of air curtain substitution:

Resultant pressure relational expression g (x) in parallel=k _n-1x ^n-1+ ... + k ₂x ²+ k ₁X+b obtains the relational expression of air leak rate of air curtain and pressure differential: $g\sqrt{\mathrm{\ΔP}}=k_{n-1}{\left(\sqrt{\mathrm{\ΔP}}\right)}^{n-1}+...+k_2{\left(\sqrt{\mathrm{\ΔP}}\right)}^2+k_1\left(\sqrt{\mathrm{\ΔP}}\right)+b;$ With the primary air pressure of each operating mode in a described n operating mode, Secondary Air pressure, the relational expression of fume side pressure and the above-mentioned air leak rate of air curtain of whole air leak rate of air curtain substitution and pressure differential obtains based on the primary air leakage under air preheater inlet flue gas condition; Measure air preheater entrance oxygen amount, Coal-fired capacity, primary air flow and carry out air preheater and use moisture as received coal, as received basis carbon, the full sulphur of as received basis, as received basis hydrogen, the as received basis oxygen of coal, the ultimate analysis data of as received basis nitrogen, and according to ultimate analysis generative theory air capacity and the theoretical wet flue gas amount of described as received basis carbon, the full sulphur of as received basis, as received basis hydrogen, as received basis oxygen, as received basis nitrogen; According to described based on the primary air leakage under air preheater inlet flue gas condition, air preheater entrance oxygen amount, Coal-fired capacity, primary air flow, theoretical air requirement and theoretical wet flue gas amount are calculated primary air leakage; Wherein, α _{Operating mode 1}Be the whole air leak rate of air curtain of operating mode 1, α ₀For carrying air leak rate of air curtain, Be the pressure reduction of 1 wind side direction fume side of operating mode, Be the pressure reduction of operating mode 1 Secondary Air side direction fume side, k _n-1... k ₂, k ₁Reaching b is coefficient, and Δ P is pressure reduction.

Further, measuring the whole air leak rate of air curtain of air preheater under n operating mode comprises: the air preheater entrance oxygen amount O that measures each operating mode in n operating mode _2EnAnd air preheater outlet oxygen amount O _2LvDescribed air preheater entrance oxygen amount O according to each operating mode _2EnAnd air preheater outlet oxygen amount O _2LvCalculate the whole air leak rate of air curtain α of this operating mode _L, whole air leak rate of air curtain ${\mathrm{\α}}_L=90\frac{O_{2\mathrm{Lv}}-O_{2\mathrm{EN}}}{21-O_{2\mathrm{En}}}.$

Further, when described n is 2, g (x)=k ₁X+b, the relational expression of air leak rate of air curtain and pressure differential is:

When described n is 3, g (x)=k ₂x ²+ k ₁X+b, the relational expression of air leak rate of air curtain and pressure differential is: $g\sqrt{\mathrm{\ΔP}}=k_2{\left(\sqrt{\mathrm{\ΔP}}\right)}^2+k_1\left(\sqrt{\mathrm{\ΔP}}\right)+b.$

The beneficial effect of the embodiment of the present invention is, the relation of finding the solution air leak rate of air curtain and pressure reduction by measuring air leak rate of air curtain under multiple condition is measured the air leak rate of air curtain of a wind, can avoid in prior art the danger of bringing and the high level error of the air quantity of directly measurement one time wind gateway.

Description of drawings

In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, the below will do to introduce simply to the accompanying drawing of required use in embodiment or description of the Prior Art, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain according to these accompanying drawings other accompanying drawing.In the accompanying drawings:

Fig. 1 is typical rotary regenerative air preheater structural representation;

Fig. 2 is the three-dimensional sealing schematic diagram of air preheater;

Fig. 3 is gaging hole position and the condition of work schematic diagram of primary air leakage when directly measuring;

Fig. 4 is embodiment of the present invention air preheater primary air leakage measuring method process flow diagram.

Embodiment

For the purpose, technical scheme and the advantage that make the embodiment of the present invention is clearer, below in conjunction with accompanying drawing, the embodiment of the present invention is described in further details.At this, illustrative examples of the present invention and explanation thereof are used for explanation the present invention, but not as a limitation of the invention.

The present invention is mainly according to the relation of air preheater air leakage rate and wind, Secondary Air operating pressure, by measuring the air preheater air leakage rate under the different pressures operating condition, measures the air leak rate of air curtain of a wind.

For any seal pad of air preheater, relation below existing:

$\frac{{\mathrm{\α}}_{L1}}{{\mathrm{\α}}_{L2}}=\sqrt{\frac{\mathrm{\Δ}{P}_1}{\mathrm{\Δ}{P}_2}}---\left(2\right)$

Wherein, α _L1Be the whole air leak rate of air curtain of a wind, α _L2Be the whole air leak rate of air curtain of Secondary Air, Δ P ₁, Δ P ₂Be respectively wind, Secondary Air pressure reduction.

Can derive according to following formula:

${\mathrm{\α}}_L=g\left(\sqrt{\mathrm{\ΔP}}\right)---\left(3\right)$

Wherein, α _LBe whole air leak rate of air curtain, Δ P is pressure reduction.

Concerning air preheater, there are three and leak out, namely wind direction Secondary Air leaks out, the secondary wind direction fume side is leaked out, a wind direction fume side is leaked out, and has like this three air leak rate of air curtain, that is: α _{L1 → 2}, α _{L2 → g}And α _{L1 → g}Under a certain operating mode, the pass that can measure its air leak rate of air curtain by the oxygen amount before and after air preheater is:

${\mathrm{\α}}_L={\mathrm{\α}}_{L1\→g}+{\mathrm{\α}}_{L2\→g}+a_0=g\left(\sqrt{\mathrm{\Δ}{P}_{1\→g}}\right)+g\left(\sqrt{\mathrm{\Δ}{P}_{2\→g}}\right)+a_0---\left(4\right)$

In formula (4), α ₀For carrying air leak rate of air curtain, main relevant with the air preheater rotating speed.Most of air preheater rotating speed is consistent, carries air leak rate of air curtain and can think 1%.In most of situation, the primary and secondary air flow area is identical, so can think and carried to leak out and be 0.5% by what wind passage, a secondary air channel were taken out of.α in addition _LBe based on the whole air leak rate of air curtain of air preheater inlet flue gas flow, need conversion to the benchmark of primary air flow, i.e. the benchmark of primary air flow, this need to be to the primary air leakage α based on the smoke inlet flow _{L1 → g}+ α _{L1 → 2}Take advantage of a coefficient, that is:

Wherein

Wherein, 1.31 be the density of flue gas under standard state, Coal-fired capacity, primary air measuring can be by the data acquisitions in dcs (Distributed Control System DCS), and theoretical wet flue gas amount, theoretical air requirement are calculated by coal data.The below will introduce in detail.

As shown in Figure 4, the invention provides a kind of air preheater primary air leakage measuring method, the method comprises:

Step S401: measure the primary air pressure of air preheater under n operating mode, Secondary Air pressure, fume side pressure and whole air leak rate of air curtain, the below illustrates take n as 2 primary air pressure, Secondary Air pressure, fume side pressure and the whole air leak rate of air curtain of measuring under two operating modes.

For example record primary air pressure 12kPa in operating mode 1, Secondary Air pressure 3kPa, fume side pressure-2kPa records whole air leak rate of air curtain α ₁=7%, record primary air pressure 12kPa in operating mode 2, Secondary Air pressure 4kPa, fume side pressure-2kPa records whole air leak rate of air curtain α ₂=7.2%.

Whole air leak rate of air curtain α under above-mentioned operating mode 1 and operating mode 2 ₁And α ₂Can be by measuring air preheater entrance oxygen amount O _2EnAnd air preheater outlet oxygen amount O _2LvObtain, with the air preheater entrance oxygen amount O that records _2EnAnd air preheater outlet oxygen amount O _2LvThe computing formula of the whole air leak rate of air curtain α of substitution L:

Can obtain whole air leak rate of air curtain α _L

Step S402: with the primary air pressure of each operating mode in a described n operating mode, Secondary Air pressure, system of equations below fume side pressure and whole air leak rate of air curtain substitution (order of air leak rate of air curtain and blast is even):

Resultant pressure relational expression g (x) in parallel=k _n-1x ^n-1+ ... + k ₂x ²+ k ₁X+b obtains the relation of air leak rate of air curtain and pressure differential: $g\sqrt{\mathrm{\ΔP}}=k_{n-1}{\left(\sqrt{\mathrm{\ΔP}}\right)}^{n-1}+...+k_2{\left(\sqrt{\mathrm{\ΔP}}\right)}^2+k_1\left(\sqrt{\mathrm{\ΔP}}\right)+b.$

Wherein, α _{Operating mode 1}Be the whole air leak rate of air curtain of operating mode 1, α ₀For carrying air leak rate of air curtain, Be the pressure reduction of 1 wind side direction fume side of operating mode, Be the pressure reduction of operating mode 1 Secondary Air side direction fume side, k _n-1... k ₂, k ₁Reaching b is coefficient, and Δ P is pressure reduction.

For the situation of said n=2, with the above-mentioned operating mode 1 that records and the primary air pressure under operating mode 2 conditions, Secondary Air pressure in fume side pressure and whole air leak rate of air curtain substitution system of equations (7), can obtain:

Operating mode 1:

Operating mode 2:

N is 2 o'clock, pressure dependence formula g (x)=k _n-1x ^n-1+ ... + k ₂x ²+ k ₁X+b can be reduced to: g (x)=k ₁X+b, the relational expression of air leak rate of air curtain and pressure differential $g\sqrt{\mathrm{\ΔP}}=k_{n-1}{\left(\sqrt{\mathrm{\ΔP}}\right)}^{n-1}+...+k_2{\left(\sqrt{\mathrm{\ΔP}}\right)}^2+k_1\left(\sqrt{\mathrm{\ΔP}}\right)+b$ Can be reduced to: $g\sqrt{\mathrm{\ΔP}}=k_1\left(\sqrt{\mathrm{\ΔP}}\right)+b.$

Suppose g (x)=kx+b, (8), (9) that are obtained by two operating modes can obtain:

3.74k+2.45k+2b＝6.19k+2b＝7.2-1＝6.2(10)

3.74k+2.24k+2b＝5.98k+2b＝7-1＝6(11)

Can be tried to achieve by formula (10), (11):

k＝0.95，b＝0.3

Air leak rate of air curtain α _LWith the pass of pressure be:

$g\left(\sqrt{\mathrm{\ΔP}}\right)=0.95\sqrt{\mathrm{\ΔP}}+0.3.$

Step S403: with the primary air pressure of each operating mode in a described n operating mode, Secondary Air pressure, the relational expression of fume side pressure and the above-mentioned air leak rate of air curtain of whole air leak rate of air curtain substitution and pressure differential obtains based on the primary air leakage under air preheater inlet flue gas condition.

Under the condition of operating mode 1, based on the primary air leakage under air preheater inlet flue gas condition:

${\mathrm{\α}}_{L1\→g}+{\mathrm{\α}}_{L1\→2}=(0.95\sqrt{12-(-2)}+0.3)+(0.95\sqrt{12-3}+0.3)+0.5{\mathrm{\α}}_0=0.95*(3.74+3)+$

$0.6+0.5=7.5.$

Under the condition of operating mode 2, based on the primary air leakage under air preheater inlet flue gas condition:

${\mathrm{\α}}_{L1\→g}+{\mathrm{\α}}_{L1\→2}=(0.95\sqrt{12-(-2)}+0.3)+(0.95\sqrt{12-4}+0.3)+0.5{\mathrm{\α}}_0=0.95*(3.74+2.83)$

$+0.6+0.5=7.3.$

Step S404: measure air preheater entrance oxygen amount, Coal-fired capacity, primary air flow and measurement air preheater entrance oxygen amount, Coal-fired capacity, primary air flow and carry out air preheater and use moisture as received coal, as received basis carbon, the full sulphur of as received basis, as received basis hydrogen, the as received basis oxygen of coal, the ultimate analysis data of as received basis nitrogen, and according to ultimate analysis generative theory air capacity and the theoretical wet flue gas amount of described as received basis carbon, the full sulphur of as received basis, as received basis hydrogen, as received basis oxygen, as received basis nitrogen.

Suppose that getting coal sample chemical examination used at that time coal and measure the parameter of gained and be:

The as received basis total moisture	M ar	％	16.20
				The as received basis ash content	A ar	％	9.13
The as received basis volatile matter	V ar	％	27.57
				As received basis fixed carbon	FC ar	％	47.10
As received basis carbon	C ar	％	61.52
				As received basis hydrogen	H ar	％	3.67
As received basis nitrogen	N ar	％	0.80
				The full sulphur of as received basis	S t，ar	％	0.31
As received basis oxygen	O ar	％	8.37
				The as received basis net calorific value	Q net，ar	kJ/kg	22740.00

According to the above-mentioned ultimate analysis data that record, can get theoretical air requirement:

V ₀＝0.0889(C _ar+0.0375S _ar)+0.265H _ar-0.0333O _ar＝6.17Nm ³/kg。

According to the above-mentioned ultimate analysis data that record, can get theoretical wet flue gas amount and be:

V _FG0＝0.0889(C _ar+0.0375S _ar)+0.21H _ar-0.0263O _ar+0.008N _ar+0.0124(9H _ar-M _ar)＝6.67Nm ³/kg。

The air preheater entrance oxygen amount of measuring is O _2En=4%, DCS showed that Coal-fired capacity was at that time: B=120t/h, DCS show that primary air flow is: G _PrA=204t/h.

Step S405: according to described based on the primary air leakage under air preheater inlet flue gas condition, air preheater entrance oxygen amount, Coal-fired capacity, primary air flow, theoretical air requirement and theoretical wet flue gas amount are calculated primary air leakage.

According to the air preheater entrance oxygen amount that step S404 measures, Coal-fired capacity, primary air flow, theoretical air requirement and theoretical wet flue gas amount can calculate:

Last according to based on the primary air leakage under air preheater inlet flue gas condition, can calculate that the primary air leakage based on primary air flow is under operating mode 1 condition:

α _{Wind of L}=ξ (α _{L1 → g}+ α _{L1 → 2})=6.23*7.5%=46.7%.

In like manner also can calculate under operating mode 2 conditions based on the primary air leakage of primary air flow, repeat no more here.

N is 2 o'clock, pressure dependence formula g (x)=k _n-1x ^n-1+ ... + k ₂x ²+ k ₁X+b can be reduced to: g (x)=k ₁X+b, the relational expression of air leak rate of air curtain and pressure differential $g\sqrt{\mathrm{\ΔP}}=k_{n-1}{\left(\sqrt{\mathrm{\ΔP}}\right)}^{n-1}+...+k_2{\left(\sqrt{\mathrm{\ΔP}}\right)}^2+k_1\left(\sqrt{\mathrm{\ΔP}}\right)+b$ Can be reduced to: $g\sqrt{\mathrm{\ΔP}}=k_1\left(\sqrt{\mathrm{\ΔP}}\right)+b.$

N is 3 o'clock, pressure dependence formula g (x)=k _n-1x ^n-1+ ... + k ₂x ²+ k ₁X+b can be reduced to: g (x)=k ₂x ²+ k ₁X+b, the relational expression of air leak rate of air curtain and pressure differential $g\sqrt{\mathrm{\ΔP}}=k_{n-1}{\left(\sqrt{\mathrm{\ΔP}}\right)}^{n-1}+...+k_2{\left(\sqrt{\mathrm{\ΔP}}\right)}^2+k_1\left(\sqrt{\mathrm{\ΔP}}\right)+b$ Can be reduced to:

Need 3 operating points of test, with the primary air pressure of measuring under 3 working conditions, Secondary Air pressure, fume side pressure and whole air leak rate of air curtain be substitution system of equations (7) respectively, and combination

Obtain k ₁, k ₂And the b value, then obtain air leak rate of air curtain α _LRelational expression with pressure, calculate under each working condition based on the primary air leakage under air preheater inlet flue gas condition, last basis is based on the primary air leakage under air preheater inlet flue gas condition, air preheater entrance oxygen amount, Coal-fired capacity, primary air flow, theoretical air requirement and theoretical wet flue gas amount are calculated primary air leakage.

In like manner, as n greater than 3 the time, also can by measure under n operating mode primary air pressure, Secondary Air pressure, fume side pressure and whole air leak rate of air curtain, the method when according to said n being obtains primary air leakage, repeats no more.

The present invention only situation take n as 2 describes the present invention in detail, is not for limiting the written or printed documents scope of invention, and those skilled in the art can be easily is 2 the situation primary air leakage when obtaining n and being any natural number according to n.

The beneficial effect of the embodiment of the present invention is, the relation of finding the solution air leak rate of air curtain and pressure reduction by measuring air leak rate of air curtain under multiple condition is measured the air leak rate of air curtain of a wind, can avoid in prior art the danger of bringing and the high level error of the air quantity of directly measurement one time wind gateway.

Above-described specific embodiment; purpose of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the above is only specific embodiments of the invention; the protection domain that is not intended to limit the present invention; within the spirit and principles in the present invention all, any modification of making, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims (5)

1. an air preheater primary air leakage measuring method, is characterized in that, described method comprises:

Measure the primary air pressure of air preheater under n operating mode, Secondary Air pressure, fume side pressure and whole air leak rate of air curtain;

With the primary air pressure of each operating mode in a described n operating mode, Secondary Air pressure, system of equations below fume side pressure and whole air leak rate of air curtain substitution:

Resultant pressure relational expression g (x) in parallel=k _n-1x ^n-1+ ... + k ₂x ²+ k ₁X+b obtains the relation of air leak rate of air curtain and pressure differential: $g\sqrt{\mathrm{\ΔP}}=k_{n-1}{\left(\sqrt{\mathrm{\ΔP}}\right)}^{n-1}+...+k_2{\left(\sqrt{\mathrm{\ΔP}}\right)}^2+k_1\left(\sqrt{\mathrm{\ΔP}}\right)+b;$

With the primary air pressure of each operating mode in a described n operating mode, Secondary Air pressure, the relational expression of fume side pressure and the above-mentioned air leak rate of air curtain of whole air leak rate of air curtain substitution and pressure differential obtains based on the primary air leakage under air preheater inlet flue gas condition;

Measure air preheater entrance oxygen amount, Coal-fired capacity, primary air flow and carry out air preheater and use moisture as received coal, as received basis carbon, the full sulphur of as received basis, as received basis hydrogen, the as received basis oxygen of coal, the ultimate analysis of as received basis nitrogen, and according to ultimate analysis data generative theory air capacity and the theoretical wet flue gas amount of described as received basis carbon, the full sulphur of as received basis, as received basis hydrogen, as received basis oxygen, as received basis nitrogen;

According to described based on the primary air leakage under air preheater inlet flue gas condition, air preheater entrance oxygen amount, Coal-fired capacity, primary air flow, theoretical air requirement and theoretical wet flue gas amount are calculated primary air leakage;

Wherein, α _{Operating mode 1}Be the whole air leak rate of air curtain of operating mode 1, α ₀For carrying air leak rate of air curtain,

Be the pressure reduction of 1 wind side direction fume side of operating mode,

Be the pressure reduction of operating mode 1 Secondary Air side direction fume side, k _n-1... k ₂, k ₁Reaching b is coefficient, and Δ P is pressure reduction.

2. air preheater primary air leakage measuring method as claimed in claim 1, is characterized in that, when described n is 2, and g (x)=k ₁X+b.

3. air preheater primary air leakage measuring method as claimed in claim 1, is characterized in that, the relational expression of air leak rate of air curtain and pressure differential is:

4. air preheater primary air leakage measuring method as claimed in claim 1, is characterized in that, when described n is 3, and g (x)=k ₂x ²+ k ₁X+b.

5. air preheater primary air leakage measuring method as claimed in claim 4, is characterized in that, the relational expression of air leak rate of air curtain and pressure differential is: $g\sqrt{\mathrm{\ΔP}}=k_2{\left(\sqrt{\mathrm{\ΔP}}\right)}^2+k_1\left(\sqrt{\mathrm{\ΔP}}\right)+b.$

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