CN109783904A - A kind of width parameter area carbon dioxide physical property method for solving - Google Patents

A kind of width parameter area carbon dioxide physical property method for solving Download PDF

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CN109783904A
CN109783904A CN201811626329.3A CN201811626329A CN109783904A CN 109783904 A CN109783904 A CN 109783904A CN 201811626329 A CN201811626329 A CN 201811626329A CN 109783904 A CN109783904 A CN 109783904A
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enthalpy
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carbon dioxide
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CN109783904B (en
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吴攀
单建强
高春天
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Xian Jiaotong University
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Abstract

The invention discloses a kind of wide parameter area carbon dioxide physical property method for solving, are iterated solution using actual gas state equation in the region of carbon dioxide critical point;Physical property is carried out using fit correlation formula in the region far from carbon dioxide critical point and carries out direct solution;Interpolation solution is carried out using fit correlation formula and actual gas state equation in borderline region, saturated solution enthalpy, saturated air enthalpy, temperature, specific volume, thermal conductivity and dynamic viscosity physical parameter is calculated.The present invention had not only guaranteed the computational accuracy of carbon dioxide, but also promoted the solving speed of reactor program of numerical calculation.

Description

A kind of width parameter area carbon dioxide physical property method for solving
Technical field
The invention belongs to nuclear reactor safety analytical calculation technical fields, and in particular to a kind of width parameter area carbon dioxide Physical property method for solving.
Background technique
Supercritical carbon dioxide Brayton cycle has many advantages, such as that the thermal efficiency is high, system simplification is compact, is to have very much prospect Forth generation nuclear reactor energy conversion system.When supercritical carbon dioxide Brayton cycle steady-state operation, at suction port of compressor Supercritical carbon dioxide be in Near The Critical Point, carbon dioxide will undergo violent and rapid physical property to change, carbon dioxide Specific volume, specific heat, the key physical parameter such as thermal conductivity can be distorted.In addition, in transient state or accident, supercritical carbon dioxide The operating status point of Brayton cycle will undergo large-scale physical property to change, therefore, accurate carbon dioxide Calculation of Physical Properties method, For realizing bistable design, transient control strategy and the crash analysis of supercritical carbon dioxide Brayton cycle reactor, With very important use value.
The calculation method of thermodynamic fluid physical property mainly has diagram method, state Equation Method and fit correlation formula method three at present Class.Diagram method is the thermal transport cofficients for calculating fluid manufactured figure and table, and this method advantage is to be easily understood but lack Point is that computational efficiency is very low, is not suitable for large-scale thermodynamic analysis program.State Equation Method is the root of thermodynamic fluid Calculation of Physical Properties This method, this method be established based on stringent theory and experimental study, therefore such methods have the advantages that it is with high accuracy, but It is the disadvantage is that model is complicated, calculating the time, long and programming is complicated.Fit correlation formula method is that simplifying for thermodynamic fluid physical property calculates Method, this method are satisfied the relationship of certain precision by being fitted to existing thermal transport cofficients data. Since the relational expression of use is generally the simple mathematicals relational expression such as multinomial, fraction, therefore this method has and calculates simple, calculation amount It is small, computational accuracy is higher, be suitable for computer programming solve the advantages of, largely used in Thermodynamic Calculation Program.
The current main adoption status equation method of carbon dioxide thermodynamic analysis program carries out Calculation of Physical Properties, and this method can be counted Calculation obtains the higher carbon dioxide physical property of precision.But state Equation Method needs a large amount of iteration to obtain physical property as a result, when calculating Between it is long.Calculation of Physical Properties is extremely important in Thermodynamic Calculation Program, and especially in transient state Thermodynamic Calculation Program, Calculation of Physical Properties is occupied Program calculates 20% or so of time.If Calculation of Physical Properties speed is slow, will lead to the calculating speed of transient state Thermodynamic Calculation Program at It reduces again.Physical property is calculated with fit correlation formula can effectively improve computational efficiency.But carbon dioxide is in the object of Near The Critical Point Sex distortion causes the computational accuracy of fit correlation formula insufficient.
The physical property feature of carbon dioxide leads to the existing transient state that can be used for supercritical carbon dioxide reactor Brayton cycle It is unsatisfactory for requiring in computational accuracy or calculating speed with accident numerical analysis programs.It is wide urgently to develop a kind of quick and precisely solution The method of parameter area carbon dioxide physical property promotes the computational accuracy and calculating speed of transient state Thermodynamic Calculation Program.
Summary of the invention
In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is that providing a kind of wide parameter model Carbon dioxide physical property method for solving is enclosed, had not only guaranteed the computational accuracy of carbon dioxide, but also promote asking for reactor program of numerical calculation Solve speed.
The invention adopts the following technical scheme:
A kind of width parameter area carbon dioxide physical property method for solving uses actual gas in the region of carbon dioxide critical point State equation is iterated solution;Physical property solution is carried out using fit correlation formula in the region far from carbon dioxide critical point;? Borderline region carries out interpolation solution using fit correlation formula and actual gas state equation, and saturated solution enthalpy, saturation is calculated Gas enthalpy, temperature, specific volume, thermal conductivity and dynamic viscosity physical parameter.
Specifically, it is as follows to solve saturation liquid phase enthalpy using fitting of a polynomial relational expression relevant to pressure:
Wherein, hl1It (p) is the saturation liquid phase enthalpy of low-pressure area, hl2It (p) is the saturation liquid phase enthalpy of higher-pressure region, hl3(p) it is The saturation liquid phase enthalpy in interpolation area, p are pressure, and MPa, a, b, i are constant coefficient.
Specifically, it is as follows to solve saturation gas phase enthalpy using fitting of a polynomial relational expression relevant to pressure:
Wherein, hg1It (p) is saturation gas phase the enthalpy g, h of low-pressure areag2It (p) is the saturation gas phase enthalpy of higher-pressure region, hg3(p) For the saturation gas phase enthalpy in interpolation area, p is pressure, and MPa, a, b, i are constant coefficient.
Specifically, by the zoning of temperature be divided into cold-zone, overheat one area and overheat 2nd area, pressure be 0.1~ 20MPa, specific enthalpy are 200~1600kJkg-1
Further, the range for crossing cold-zone is enthalpy of saturated liquid line and critical specific enthalpy line lower boundary (312.25kJkg-1) Under, region of the pressure from 0.1MPa to 20MPa;The range for overheating an area is saturated air specific enthalpy line and critical specific enthalpy line coboundary (352.25kJ·kg-1) more than, 600kJkg-1Specific enthalpy line is hereinafter, region of the pressure from 0.1MPa to 20MPa;Overheat 2nd area Range be 600kJkg-1It is more than specific enthalpy line, 1600kJkg-1Specific enthalpy line is hereinafter, area of the pressure from 0.1MPa to 20MPa Domain.
Further, the temperature T of cold-zone is crossed1(p, h) calculates as follows:
Wherein, aijFor constant coefficient, p is pressure, and MPa, h are enthalpy, kJ/kg, p≤pcritical, h < hl(p) or p > pcritical, h≤hset10, hset10=hcritical- 20.0=312.25kJ/kg;
Overheat the temperature T in an area2(p, h) calculates as follows:
Wherein, bijFor constant coefficient, p≤pcritical, hg(p) < h≤hset20Or p > pcritical, hset11< h≤hset20, hset11=hcritical+ 20.0=352.25kJ/kg, hset20For constant ,=580kJ/kg;
Overheat the temperature T in 2nd area3(p, h) calculates as follows:
Wherein, cijFor constant coefficient, h > hset21, hset21For constant ,=620kJ/kg;
One area of interpolation was the transitional region in one area of cold-zone and overheat, temperature T4(p, h) calculates as follows:
Wherein, h is enthalpy, p > pcritical, hset10< h≤hset11
2nd area of interpolation is the transitional region for overheating an area and overheating 2nd area, temperature T5(p, h) calculates as follows:
Specifically, the zoning of specific volume was divided into cold-zone, 2nd area of state equation area, one area of overheat and overheat, pressure It is 200~1600kJkg for 0.1~20MPa, specific enthalpy-1
Further, the range for crossing cold-zone is enthalpy of saturated liquid line and 260kJkg-1Under specific enthalpy line, pressure from The region of 0.1MPa to 20MPa;State equation area uses actual gas Solving Equation of State, and range includes two parts, and first Dividing is enthalpy of saturated liquid line or less and 296kJkg-1More than specific enthalpy line, more than saturated air line and 380kJkg-1Specific enthalpy line with Under, region of the pressure from 7MPa to 7.38MPa, second part is 296kJkg-1More than specific enthalpy line and 380kJkg-1Specific enthalpy Line hereinafter, pressure from 7.38MPa to 20MPa;The range for overheating an area is saturated air line or more and 580kJkg-1Specific enthalpy line with Under, region of the pressure from 0.1MPa to 7MPa;Enthalpy is in 410kJkg-1More than specific enthalpy line and 580kJkg-1Specific enthalpy line with Under, region of the pressure from 7MPa to 20MPa;The range for overheating 2nd area is 600kJkg-1It is more than specific enthalpy line, 1600kJkg-1 Specific enthalpy line is hereinafter, region of the pressure from 0.1MPa to 20MPa.
Further, the specific volume v of cold-zone is crossed1(p, h) calculates as follows:
Wherein, aijFor constant coefficient, p≤7MPa, h < hl(p) or p > 7MPa, h≤hset30, hset30For constant ,= 260kJ/kg;
Hereby function does not calculate using Hall for state equation area:
φ (δ, τ)=φo(δ,τ)+φr(δ,τ)
Wherein, φ is the Hall not hereby energy of real gas, φoFor the Hall not hereby perfect gas part of energy, φrFor The Hall not hereby remainder of energy, δ=ρ/ρc, τ=T/Tc, ρc=467.6kg/m3, Tc=31.1 DEG C, p >=pcritical, hset00≤h≤hset01Or 7MPa≤p≤pcritical, hset00≤h≤hl(p) or 7MPa≤p≤pcritical, hg(p)≤h≤ hset01, hset00For constant ,=296kJ/kg, hset01For constant ,=380kJ/kg, pcriticalFor the critical pressure of carbon dioxide, =7.31MPa;
Overheat the specific volume v in an area3(p, h) calculates as follows:
Wherein, bijFor constant coefficient, p≤7MPa, hg(p) < h≤hset20Or p > 7MPa, hset31< h≤hset20, hset31For Constant ,=410kJ/kg;
Overheat the specific volume v in 2nd area4(p, h) calculates as follows:
Wherein, cijFor constant coefficient, h > hset21
One area of interpolation was the transition region of cold-zone and state equation area, specific volume v5(p, h) calculates as follows:
Wherein, hset30=260kJ/kg, hset00=296kJ/kg, p > 7MPa, hset30< h≤hset00
2nd area of interpolation is the transition region in one area of state equation area and overheat, specific volume v6(p, h) calculates as follows:
Wherein, hset31=410kJ/kg, hset01=380kJ/kg, p > 7MPa, hset01< h≤hset31
3rd area of interpolation is the transition region for overheating an area and overheating 2nd area, specific volume v7(p, h) calculates as follows:
Wherein, hset20=580kJ/kg, hset21=620kJ/kg, hset20< h≤hset21
Specifically, the computer capacity of thermal conductivity, in 216~1100K of temperature, pressure to 200MPa calculates as follows:
λ (ρ, T)=λ0(T)+Δλ(ρ,T)+Δλc(ρ,T)
Wherein, λ0(T) thermal conductivity in zero density low density gas is indicated, Δ λ (ρ, T) represents thin gas at identical temperature Volume density increases bring thermal conductivity and increases, Δ λc(ρ, T) represents the increase in critical point peak region thermal conductivity;
The computer capacity of dynamic viscosity is in 200~1500K of temperature, density to 1400kg/m3, it is specific as follows:
η (ρ, T)=η0(T)+Δη(ρ,T)+Δηc(ρ,T)
Wherein, η0(T) viscosity in zero density low density gas is indicated, Δ η (ρ, T) represents low density gas at identical temperature Density increases bring viscosity and increases, Δ ηc(ρ, T) represents the increase in critical point peak region viscosity.
Compared with prior art, the present invention at least has the advantages that
The one wide parameter area carbon dioxide physical property method for solving of the present invention, polynomial fitting is mutually tied with state equation It closes, can rapidly and accurately calculate the physical property such as saturated solution enthalpy, saturated air enthalpy, temperature, specific volume, thermal conductivity and dynamic viscosity ginseng Number.
Further, enthalpy of saturated liquid is calculated, in 0.6~7.377MPa, takes 6777 pressure by step-length of 1kPa Point carries out enthalpy of saturated liquid calculating, and it is 0.08% that method of the invention, which calculates maximum relative error, and calculating speed is business software 118 times of NIST PREPROP.
Further, saturated air specific enthalpy is calculated, in 0.6~7.377MPa, takes 6777 pressure by step-length of 1kPa Point carries out enthalpy of saturated liquid calculating, and it is 0.009% that method of the invention, which calculates maximum relative error, and calculating speed is business software 230 times of NIST PREPROP.
Further, for temperature computation, in 0.1~20MPa of pressure limit, step-length 0.1MPa, than enthalpy spectrum 200- 1600kJ·kg-1, step-length 2kJkg-1, take 131914 state points to be calculated, it is opposite accidentally that method of the invention calculates maximum Difference is 0.1%, and calculating speed is 15 times of business software NIST PREPROP.
Further, specific volume is calculated, in 0.1~20MPa of pressure limit, step-length 0.1MPa, than enthalpy spectrum 200- 1600kJ·kg-1, step-length 2kJkg-1, take 131914 state points to be calculated, it is opposite accidentally that method of the invention calculates maximum For difference within 1%, calculating speed is 28 times of business software NIST PREPROP.
Further, for the calculating of thermal conductivity, for maximum relative error within 5%, calculating speed is business software NIST PREPROP is suitable.
Further, for the calculating of dynamic viscosity, for maximum relative error within 5%, calculating speed is business software NIST PREPROP is suitable.
In conclusion the present invention is based on the carbon dioxide objects reported in the polynomial fitting of independent development and open source literature Property calculation relational expression and actual gas state equation, develop a carbon dioxide physical property method for solving, are used for and carbon dioxide The physical property of relevant reactor numerical analysis programs solves.Physical property solution proposes polynomial fitting and state equation combines Physical property method for solving, in the parameters such as enthalpy of saturated liquid, saturated air specific enthalpy and temperature, using the fit correlation formula of independent research Direct solution is carried out, in the parameters such as thermal conductivity and dynamic viscosity, the calculation formula delivered using open source literature is directly asked Solution, improves the calculating speed of physical property packet.In specific volume parameter, in Near The Critical Point, carbon dioxide state equation is mainly used It is iterated solution, ensure that the precision that specific volume calculates, when far from critical point, is carried out using the fit correlation formula of independent research Direct solution.
Below by drawings and examples, technical scheme of the present invention will be described in further detail.
Detailed description of the invention
Fig. 1 is temperature computation schematic diagram;
Fig. 2 is that specific volume calculates schematic diagram;
Fig. 3 is enthalpy of saturated liquid schematic diagram of calculation result, wherein (a) is that enthalpy of saturated liquid low-pressure area relational expression is opposite accidentally Difference (b) is enthalpy of saturated liquid higher-pressure region relational expression relative error;
Fig. 4 is that enthalpy of saturated liquid fit correlation formula and business software NIST REFPROP calculating speed compare;
Fig. 5 is saturated air specific enthalpy schematic diagram, wherein (a) is saturated air specific enthalpy low-pressure area relational expression relative error, (b) is Saturated air specific enthalpy higher-pressure region relational expression relative error;
Fig. 6 is that saturated air specific enthalpy fit correlation formula and business software NIST REFPROP calculating speed compare;
Fig. 7 is temperature computation result schematic diagram, wherein (a) was cold-zone temperature dependence relative error, was (b) overheat One area's temperature dependence relative error is (c) two area's temperature dependence relative errors of overheat;
Fig. 8 is that temperature foh relational expression and business software NIST REFPROP calculating speed compare;
Fig. 9 is specific volume schematic diagram of calculation result, wherein (a) was cold-zone specific volume relational expression relative error, was (b) overheat Two area's temperature dependence relative errors;
Figure 10 is that specific volume fit correlation formula and business software NIST REFPROP calculating speed compare.
Specific embodiment
The present invention provides a kind of wide parameter area carbon dioxide physical property method for solving, in the region of carbon dioxide critical point Physical property solution is carried out using fit correlation formula;In the region far from critical point, solved using actual gas state equation;? Borderline region carries out interpolation solution using fit correlation formula and actual gas state equation;Solution saturated solution enthalpy can be solved, satisfied Gentle enthalpy, temperature, specific volume, thermal conductivity and dynamic viscosity physical parameter.
The pressure and enthalpy provided according to user, substitutes into the saturated solution and saturated air enthalpy calculation formula of carbon dioxide, can Saturated solution and saturated air enthalpy is calculated.Pressure and enthalpy substitute into the temperature computation formula of carbon dioxide, available two The temperature of carbonoxide;Specific volume calculation formula is substituted into, the specific volume (or density) of carbon dioxide can be obtained.By the temperature of carbon dioxide and Density substitutes into the calculation formula of thermal conductivity and dynamic viscosity, then the thermal conductivity and dynamic viscosity of carbon dioxide can be calculated. Pass through physical property method for solving provided herein, in the case where known pressure and enthalpy, the saturated solution of available carbon dioxide The parameters such as enthalpy, saturated air enthalpy, temperature, specific volume, thermal conductivity and dynamic viscosity, these parameters can be used for the calculating of reactor numerical value Program.
A kind of wide parameter area carbon dioxide physical property method for solving of the present invention, comprising the following steps:
S1, saturation liquid phase enthalpy and saturation gas phase enthalpy are solved using fitting of a polynomial relational expression relevant to pressure;
The input parameter of saturated solution enthalpy is pressure
Wherein, hl1It (p) is the saturation liquid phase enthalpy of low-pressure area, kJ/kg, hl2It (p) is the saturation liquid phase enthalpy of higher-pressure region, KJ/kg, hl3It (p) is the saturation liquid phase enthalpy in interpolation area, kJ/kg, p are pressure, and MPa, a, b, i are constant coefficient, and occurrence is shown in Table 1.
1 enthalpy of saturated liquid fit correlation formula coefficient of table
The input parameter of saturated air enthalpy is pressure
Wherein, hg1It (p) is the saturation gas phase enthalpy of low-pressure area, kJ/kg, hg2It (p) is the saturation gas phase enthalpy of higher-pressure region, KJ/kg, hg3It (p) is the saturation gas phase enthalpy in interpolation area, kJ/kg, p are pressure, and MPa, a, b, i are constant coefficient, and occurrence is shown in Table 2.
2 saturated air specific enthalpy fit correlation formula coefficient of table
S2, temperature computation region was divided into 2nd area of cold-zone, one area of overheat and overheat, pressure is 0.1~20MPa, specific enthalpy For 200~1600kJkg-1, it is as shown in Figure 1 that actual temp calculates subregion.
The range for crossing cold-zone is enthalpy of saturated liquid line and critical specific enthalpy line lower boundary (h=hset10=312.25kJ/kg) it Under, region calculation formula of the pressure from 0.1MPa to 20MPa is as follows:
Wherein, T1(p, h) was the temperature of cold-zone, DEG C, p is pressure, and MPa, h are enthalpy, kJ/kg, aijIt is constant, specifically Value is shown in Table 3;;
Table 3 crosses cold-zone temperature foh relational expression coefficient aij
The range for overheating an area is saturated air specific enthalpy line and critical specific enthalpy line coboundary (h=hset11=352.25kJ/kg) Above, 600kJkg-1Specific enthalpy line is hereinafter, region of the pressure from 0.1MPa to 20MPa;
Wherein, T2(p, h) is the temperature for overheating an area, DEG C, p≤pcritical, hg(p) < h≤hset20Or p > pcritical, hset11< h≤hset20, hset20For constant ,=580kJ/kg, bijFor constant coefficient, occurrence is shown in Table 4;
Table 4 overheats an area temperature foh relational expression coefficient bij
The range for overheating 2nd area is 620kJkg-1It is more than specific enthalpy line, 1600kJkg-1Specific enthalpy line hereinafter, pressure from The region of 0.1MPa to 20MPa, calculation formula are as follows:
Wherein, T3(p, h) is the temperature for overheating 2nd area, DEG C, h > hset21, hset21For constant ,=620kJ/kg, cijIt is normal Coefficient, occurrence are shown in Table 5;
Table 5 overheats two area temperature foh relational expression coefficient cij
The calculation formula in one area of interpolation is as follows:
Wherein, T4(p, h) is the temperature in one area of interpolation, DEG C, p > pcritical, hset10< h≤hset11, hset10For constant, =312.25kJ/kg, hset11For constant ,=352.25kJ/kg;
The calculation formula in 2nd area of interpolation is as follows:
Wherein, T5(p, h) is the temperature in 2nd area of interpolation, DEG C, hset20< h≤hset21, hset20For constant ,=580kJ/kg, hset21For constant ,=620kJ/kg.
S3, specific volume zoning was divided into cold-zone, state equation area, one area of overheat and 2nd area of overheat and was inserted accordingly It is worth area;
Specific volume computer capacity is 0.1~20MPa of pressure, 200~1600kJkg of specific enthalpy-1, as shown in Figure 3.
The range for crossing cold-zone is enthalpy of saturated liquid line and 260kJkg-1Under specific enthalpy line, pressure is from 0.1MPa to 20MPa Region;
State equation area is iteratively solved using actual gas state equation, and range includes two parts, and first part is Below enthalpy of saturated liquid line and 296kJkg-1More than specific enthalpy line, more than saturated air line and 380kJkg-1Specific enthalpy line is hereinafter, pressure Region of the power from 7MPa to 7.38MPa, the second part are 296kJkg-1More than specific enthalpy line and 380kJkg-1Specific enthalpy line with Under, pressure is from 7.38MPa to 20MPa;
The range for overheating an area is saturated air line or more and 580kJkg-1Specific enthalpy line hereinafter, pressure from 0.1MPa to 7MPa Region;Enthalpy is in 410kJkg-1More than specific enthalpy line and 580kJkg-1Specific enthalpy line hereinafter, pressure from 7MPa to 20MPa Region.
The range for overheating 2nd area is 600kJkg-1It is more than specific enthalpy line, 1600kJkg-1Specific enthalpy line hereinafter, pressure from The region of 0.1MPa to 20MPa.
The calculation formula for crossing cold-zone is as follows:
Wherein, v1(p, h) was the specific volume of cold-zone, m3/ kg, p≤7MPa, h < hl(p) or p > 7MPa, h≤hset30, hset30For constant ,=260kJ/kg;aijSpecific value be shown in Table 6.
Table 6 crosses cold-zone specific volume fit correlation formula coefficient aij
Using Hall, hereby energy equation is not solved in state equation area:
φ (δ, τ)=φo(δ,τ)+φr(δ,τ)
Wherein, φ is the Hall not hereby energy of real gas, φoFor the Hall not hereby perfect gas part of energy, φrFor The Hall not hereby remainder of energy, δ=ρ/ρc, τ=T/Tc, ρc=467.6kg/m3, Tc=31.1 DEG C, p >=pcritical, hset00≤h≤hset01Or 7MPa≤p≤pcritical, hset00≤h≤hl(p) or 7MPa≤p≤pcritical, hg(p)≤h≤ hset01, hset00For constant ,=296kJ/kg, hset01For constant ,=380kJ/kg, pcriticalFor the critical pressure of carbon dioxide, =7.31MPa.
An area is overheated to be calculated using following relational expression:
Wherein, v3(p, h) is the specific volume for overheating an area, p≤7MPa, hg(p) < h≤hset20Or p > 7MPa, hset31< h ≤hset20, hset31For constant ,=410kJ/kg;bijSpecific value be shown in Table 7.
Table 7 overheats an area specific volume fit correlation formula coefficient bij
The calculation relational expression for overheating 2nd area is as follows:
Wherein, v4(p, h) is the specific volume for overheating 2nd area, m3/ kg, h > hset21;cijSpecific value be shown in Table 8.
Table 8 overheats two area specific volume fit correlation formula coefficient aij
Interpolation area:
Wherein, v5(p, h) is the specific volume in one area of interpolation, m3/ kg, hset30=260kJ/kg, hset00=296kJ/kg, p > 7MPa, hset10< h≤hset00
Wherein, v6(p, h) is the specific volume in 2nd area of interpolation, m3/ kg, hset31=410kJ/kg is hset01=380kJ/kg, p > 7MPa, hset01< h≤hset31
Wherein, v7(p, h) is the specific volume in 3rd area of interpolation, m3/ kg, hset20For constant ,=580kJ/kg, hset21For constant, =620kJ/kg, hset20< h≤hset21
S4, thermal conductivity is calculated, computer capacity is in 216~1100K of temperature, pressure to 200MPa;
λ (ρ, T)=λ0(T)+Δλ(ρ,T)+Δλc(ρ,T)
Wherein, λ0(T) thermal conductivity in zero density low density gas is indicated, Δ λ (ρ, T) represents thin gas at identical temperature Volume density increases bring thermal conductivity and increases, Δ λc(ρ, T) represents the increase in critical point peak region thermal conductivity.
S5, dynamic viscosity is calculated.
Computer capacity is in 200~1500K of temperature, density to 1400kg/m3
η (ρ, T)=η0(T)+Δη(ρ,T)+Δηc(ρ,T)
Wherein, η0(T) viscosity in zero density low density gas is indicated, Δ η (ρ, T) represents low density gas at identical temperature Density increases bring viscosity and increases, Δ ηc(ρ, T) represents the increase in critical point peak region viscosity.
In order to make the object, technical scheme and advantages of the embodiment of the invention clearer, below in conjunction with the embodiment of the present invention In attached drawing, technical scheme in the embodiment of the invention is clearly and completely described, it is clear that described embodiment is A part of the embodiment of the present invention, instead of all the embodiments.The present invention being described and shown in usually here in attached drawing is real The component for applying example can be arranged and be designed by a variety of different configurations.Therefore, below to the present invention provided in the accompanying drawings The detailed description of embodiment be not intended to limit the range of claimed invention, but be merely representative of of the invention selected Embodiment.Based on the embodiments of the present invention, those of ordinary skill in the art are obtained without creative efforts The every other embodiment obtained, shall fall within the protection scope of the present invention.
Enthalpy of saturated liquid is calculated, in 0.6~7.377MPa, takes 6777 pressure spots to be saturated by step-length of 1kPa Liquor ratio enthalpy calculates, and it is 0.08% that method of the invention, which calculates maximum relative error, as shown in Figure 3;Calculating speed is business software 118 times of NIST PREPROP, as shown in Figure 4.
Saturated air specific enthalpy is calculated, in 0.6~7.377MPa, takes 6777 pressure spots to be saturated by step-length of 1kPa Liquor ratio enthalpy calculates, and it is 0.009% that method of the invention, which calculates maximum relative error, as shown in Figure 5;Calculating speed is business software 230 times of NIST PREPROP, as shown in Figure 6.
For temperature computation, in 0.1~20MPa of pressure limit, step-length 0.1MPa, than enthalpy spectrum 200-1600kJkg-1、 Step-length 2kJkg-1, take 131914 state points to be calculated, it is 0.25% that method of the invention, which calculates maximum relative error, such as Shown in Fig. 7;Calculating speed is 15 times of business software NIST PREPROP, as shown in Figure 8.
Specific volume is calculated, in 0.1~20MPa of pressure limit, step-length 0.1MPa, than enthalpy spectrum 200-1600kJkg-1、 Step-length 2kJkg-1, take 131914 state points to be calculated, method of the invention calculates maximum relative error within 1%, As shown in figure 9, calculating speed is 28 times of business software NIST PREPROP, as shown in Figure 10.
Calculating for thermal conductivity, for maximum relative error within 5%, calculating speed is business software NIST PREPROP Quite.
Calculating for dynamic viscosity, for maximum relative error within 5%, calculating speed is business software NIST PREPROP is suitable.
The above content is merely illustrative of the invention's technical idea, and this does not limit the scope of protection of the present invention, all to press According to technical idea proposed by the present invention, any changes made on the basis of the technical scheme each falls within claims of the present invention Protection scope within.

Claims (10)

1. a kind of width parameter area carbon dioxide physical property method for solving, which is characterized in that adopted in the region of carbon dioxide critical point Solution is iterated with actual gas state equation;Object is carried out using fit correlation formula in the region far from carbon dioxide critical point Property solve;Interpolation solution is carried out using fit correlation formula and actual gas state equation in borderline region, saturated solution is calculated Enthalpy, saturated air enthalpy, temperature, specific volume, thermal conductivity and dynamic viscosity physical parameter.
2. width parameter area carbon dioxide physical property method for solving according to claim 1, which is characterized in that use and pressure It is as follows that relevant fitting of a polynomial relational expression solves saturation liquid phase enthalpy:
Wherein, hl1It (p) is the saturation liquid phase enthalpy of low-pressure area, hl2It (p) is the saturation liquid phase enthalpy of higher-pressure region, hl3It (p) is interpolation The saturation liquid phase enthalpy in area, p are pressure, and MPa, a, b, i are constant coefficient.
3. width parameter area carbon dioxide physical property method for solving according to claim 1, which is characterized in that use and pressure It is as follows that relevant fitting of a polynomial relational expression solves saturation gas phase enthalpy:
Wherein, hg1It (p) is saturation gas phase the enthalpy g, h of low-pressure areag2It (p) is the saturation gas phase enthalpy of higher-pressure region, hg3It (p) is slotting It is worth the saturation gas phase enthalpy in area, p is pressure, and MPa, a, b, i are constant coefficient.
4. width parameter area carbon dioxide physical property method for solving according to claim 1, which is characterized in that by the meter of temperature It calculates region and was divided into 2nd area of cold-zone, one area of overheat and overheat, pressure is 0.1~20MPa, specific enthalpy is 200~1600kJkg-1
5. width parameter area carbon dioxide physical property method for solving according to claim 4, which is characterized in that cross the model of cold-zone Enclose is enthalpy of saturated liquid line and critical specific enthalpy line lower boundary (312.25kJkg-1) under, area of the pressure from 0.1MPa to 20MPa Domain;
The range for overheating an area is saturated air specific enthalpy line and critical specific enthalpy line coboundary (352.25kJkg-1) more than, 600kJ kg-1Specific enthalpy line is hereinafter, region of the pressure from 0.1MPa to 20MPa;
The range for overheating 2nd area is 600kJkg-1It is more than specific enthalpy line, 1600kJkg-1Specific enthalpy line hereinafter, pressure from 0.1MPa to The region of 20MPa.
6. width parameter area carbon dioxide physical property method for solving according to claim 5, which is characterized in that cross the temperature of cold-zone Spend T1(p, h) calculates as follows:
Wherein, aijFor constant coefficient, p is pressure, and MPa, h are enthalpy, kJ/kg, p≤pcritical, h < hl(p) or p > pcritical, h ≤hset10, hset10=hcritical- 20.0=312.25kJ/kg;
Overheat the temperature T in an area2(p, h) calculates as follows:
Wherein, bijFor constant coefficient, p≤pcritical, hg(p) < h≤hset20Or p > pcritical, hset11< h≤hset20, hset11 =hcritical+ 20.0=352.25kJ/kg, hset20For constant, hset20=580kJ/kg;
Overheat the temperature T in 2nd area3(p, h) calculates as follows:
Wherein, cijFor constant coefficient, h > hset21, hset21For constant, hset21=620kJ/kg;
One area of interpolation was the transitional region in one area of cold-zone and overheat, temperature T4(p, h) calculates as follows:
Wherein, h is enthalpy, p > pcritical, hset10< h≤hset11
2nd area of interpolation is the transitional region for overheating an area and overheating 2nd area, temperature T5(p, h) calculates as follows:
7. width parameter area carbon dioxide physical property method for solving according to claim 1, which is characterized in that by the meter of specific volume Calculate region and be divided into cold-zone, 2nd area of state equation area, one area of overheat and overheat, pressure is 0.1~20MPa, specific enthalpy be 200~ 1600kJ·kg-1
8. width parameter area carbon dioxide physical property method for solving according to claim 7, which is characterized in that cross the model of cold-zone Enclose is enthalpy of saturated liquid line and 260kJkg-1Under specific enthalpy line, region of the pressure from 0.1MPa to 20MPa;
State equation area uses actual gas Solving Equation of State, and range includes two parts, and first part is enthalpy of saturated liquid line Below and 296kJkg-1More than specific enthalpy line, more than saturated air line and 380kJkg-1Specific enthalpy line hereinafter, pressure from 7MPa to The region of 7.38MPa, second part are 296kJkg-1More than specific enthalpy line and 380kJkg-1Specific enthalpy line hereinafter, pressure from 7.38MPa arriving 20MPa;
The range for overheating an area is saturated air line or more and 580kJkg-1Specific enthalpy line is hereinafter, area of the pressure from 0.1MPa to 7MPa Domain;Enthalpy is in 410kJkg-1More than specific enthalpy line and 580kJkg-1Specific enthalpy line is hereinafter, region of the pressure from 7MPa to 20MPa;
The range for overheating 2nd area is 600kJkg-1It is more than specific enthalpy line, 1600kJkg-1Specific enthalpy line hereinafter, pressure from 0.1MPa to The region of 20MPa.
9. width parameter area carbon dioxide physical property method for solving according to claim 8, which is characterized in that cross the ratio of cold-zone Hold v1(p, h) calculates as follows:
Wherein, aijFor constant coefficient, p≤7MPa, h < hl(p) or p > 7MPa, h≤hset30, hset30For constant ,=260kJ/kg;
Hereby function does not calculate using Hall for state equation area:
φ (δ, τ)=φo(δ,τ)+φr(δ,τ)
Wherein, φ is the Hall not hereby energy of real gas, φoFor the Hall not hereby perfect gas part of energy, φrFor Hall The not hereby remainder of energy, δ=ρ/ρc, τ=T/Tc, ρc=467.6kg/m3, Tc=31.1 DEG C, p >=pcritical, hset00≤h ≤hset01Or 7MPa≤p≤pcritical, hset00≤h≤hl(p) or 7MPa≤p≤pcritical, hg(p)≤h≤hset01, hset00 For constant ,=296kJ/kg, hset01For constant ,=380kJ/kg, pcriticalFor the critical pressure of carbon dioxide ,= 7.31MPa;
Overheat the specific volume v in an area3(p, h) calculates as follows:
Wherein, bijFor constant coefficient, p≤7MPa, hg(p) < h≤hset20Or p > 7MPa, hset31< h≤hset20, hset31It is normal Number ,=410kJ/kg;
Overheat the specific volume v in 2nd area4(p, h) calculates as follows:
Wherein, cijFor constant coefficient, h > hset21
One area of interpolation was the transition region of cold-zone and state equation area, specific volume v5(p, h) calculates as follows:
Wherein, hset30=260kJ/kg, hset00=296kJ/kg, p > 7MPa, hset30< h≤hset00
2nd area of interpolation is the transition region in one area of state equation area and overheat, specific volume v6(p, h) calculates as follows:
Wherein, hset31=410kJ/kg, hset01=380kJ/kg, p > 7MPa, hset01< h≤hset31
3rd area of interpolation is the transition region for overheating an area and overheating 2nd area, specific volume v7(p, h) calculates as follows:
Wherein, hset20=580kJ/kg, hset21=620kJ/kg, hset20< h≤hset21
10. width parameter area carbon dioxide physical property method for solving according to claim 1, which is characterized in that thermal conductivity Computer capacity calculates as follows in 216~1100K of temperature, pressure to 200MPa:
λ (ρ, T)=λ0(T)+Δλ(ρ,T)+Δλc(ρ,T)
Wherein, λ0(T) thermal conductivity in zero density low density gas is indicated, it is close that Δ λ (ρ, T) represents low density gas at identical temperature Degree increases bring thermal conductivity and increases, Δ λc(ρ, T) represents the increase in critical point peak region thermal conductivity;
The computer capacity of dynamic viscosity is in 200~1500K of temperature, density to 1400kg/m3, it is specific as follows:
η (ρ, T)=η0(T)+Δη(ρ,T)+Δηc(ρ,T)
Wherein, η0(T) viscosity in zero density low density gas is indicated, Δ η (ρ, T) represents low density gas density at identical temperature It increases bring viscosity to increase, Δ ηc(ρ, T) represents the increase in critical point peak region viscosity.
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