CN105728229A - Rapid mist spray water drop average diameter estimation method based on nozzle power parameters - Google Patents

Rapid mist spray water drop average diameter estimation method based on nozzle power parameters Download PDF

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Publication number
CN105728229A
CN105728229A CN201610114874.9A CN201610114874A CN105728229A CN 105728229 A CN105728229 A CN 105728229A CN 201610114874 A CN201610114874 A CN 201610114874A CN 105728229 A CN105728229 A CN 105728229A
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China
Prior art keywords
nozzle
average diameter
mist spray
spray water
mvd
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Pending
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CN201610114874.9A
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Chinese (zh)
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唐虎
成竹
吴敬涛
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AVIC Aircraft Strength Research Institute
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AVIC Aircraft Strength Research Institute
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Priority to CN201610114874.9A priority Critical patent/CN105728229A/en
Publication of CN105728229A publication Critical patent/CN105728229A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B12/00—Arrangements for controlling delivery; Arrangements for controlling the spray area
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
    • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
    • B05B9/00—Spraying apparatus for discharge of liquids or other fluent material, without essentially mixing with gas or vapour
    • B05B9/03—Spraying apparatus for discharge of liquids or other fluent material, without essentially mixing with gas or vapour characterised by means for supplying liquid or other fluent material

Abstract

The invention discloses a rapid mist spray water drop average diameter estimation method based on nozzle power parameters, and belongs to the field of ground freezing experiments. The method comprises the steps that firstly, the water pressure value Pw and the air pressure value Pa at the position of a nozzle and the maximum air pressure value Pmax determined according to an experiment are obtained, wherein mist spray can be formed at the position of the nozzle at the maximum air pressure value Pmax; and then, the average diameter MVD of mist spray water drops is estimated according to the formula shown in the specification, wherein K, m and n are constants, and the value of K, the value of m and the value of n are obtained in the manner that the formula (1) is subjected to linear treatment and then subjected to least square fit with the MVD obtained through experiment measurement. Compared with the prior art, according to the rapid mist spray water drop average diameter estimation method based on the nozzle power parameters, the mist spray water drop average diameter with the smaller error is obtained through fewer input parameters, the debugging period is shortened, and meanwhile the rapid mist spray water drop average diameter estimation method is more economical and saves more energy.

Description

A kind of spraying water droplet average diameter Method of fast estimating based on nozzle kinetic parameter
Technical field
The invention belongs to icing experiment field, ground, be mainly used in the simulation of ground icing Experimental Establishment cloud and mist and choose with icing experiment parameter.It is specifically related to a kind of spraying water droplet average diameter Method of fast estimating based on nozzle kinetic parameter.
Background technology
Water droplet average diameter (MeanVolumeDiameter, MVD) is one of important parameter characterizing icing cloud, affects charging properties.Icing Experimental Establishment in ground makes water fogging frequently with the air-assisted nozzle of internal-mixing and sprays the method simulation icing cloud and mist to low-temperature airflow after becoming little water droplet.At present more about all kinds spraying droplet average diameter Forecasting Methodology, but the method being applied to the estimation of internal-mixing air-assisted nozzle spray water droplet average diameter is less.Water jet and the high velocity air of the air-assisted nozzle of internal-mixing mix strongly at mixing chamber so that the nowed forming high complexity of gas water mixture, the forming process of water droplet is not also fully understood.Such as based on the nanospray experiment data of the air-assisted nozzle of multiple internal-mixings, it is derived the air-assisted nozzle spray MVD estimation equation of internal-mixing:
M V D = 20 μ L 0.5 m · L 0.1 ( 1 + m · A m · L ) 0.5 b 0.1 σ 0.2 ρ A - 0.3 U R - 1.0
μ in above formulaLFor the viscosity of liquid,WithBeing the mass flow of liquid and air, b is the height of air ring, and σ is the surface tension of liquid, ρAIt is atmospheric density, URIt it is the relative velocity of jet and air.This estimation equation does not account for collision and the polymerization behavior of drop, and therefore the suitability for water spray is poor.Consider the polymerization behavior of water droplet, define new correction formula:
M V D = 20 μ L 0.5 m · L 0.1 ( 1 + m · A m · L ) 0.5 b 0.1 σ 0.2 ρ A - 0.3 U R - 1.0 [ 1 + 2.5 ( m · A m · L ) 0.6 m · L 0.1 ]
The air-assisted nozzle spray MVD estimation of follow-up internal-mixing is the Sauter mean diameter (SauterMeanDiameter paying close attention to and being applied to engine fuel spraying field more, SMD), and be concerned with MVD in the research that freezes, so SMD evaluation method is not discussed by place.
But, the calculating of above-mentioned two formulas also needs to other nozzle structural parameters, such as nozzle physical dimension, spray liquids physical property and flow parameter etc., above-mentioned two formulas are chosen respectively two groups of nozzle kinetic parameter (NozzleDynamicParameters, NDPs) value of calculation and experiment value are compared and find that error is bigger by operating mode, all more than 10%, it is unsuitable for engineer applied.In actual nozzle use procedure, pressure and the flow of nozzle can be adjusted according to the actual requirements, to reach the MVD and Liquid water content (LiquidWaterContent of requirement, LWC) combination condition, but nozzle flow adjustment difficulty is bigger, giving timing at pressure, the maximum stream flow of nozzle may determine that.Above-mentioned estimation equation and correction form thereof are all set up MVD relational expression with the form of mass flow, and the input parameter that these relational expressions require is more, and the calculating process of parameter is loaded down with trivial details, be difficult to obtain, and this makes troubles to practical engineering application.When nozzle uses, it is mostly directly to regulate NDPs, namely directly invokes the hydraulic pressure value Pw and atmospheric pressure value Pa at nozzle place, therefore, if MVD can directly be estimated according to NDPs, can be more convenient.
Summary of the invention
In order to solve the problems referred to above, reach the purpose of estimation MVD by directly invoking NDPs, the invention provides a kind of new spraying water droplet average diameter Method of fast estimating and the estimation equation of correspondence.
The present invention focuses primarily on the spraying water droplet distribution of sizes near nozzle outlet area, sets up a kind of water droplet average diameter (MVD) estimation equation based on nozzle kinetic parameter (NDPs), helps the debugging of ground icing Experimental Establishment cloud parameter.
The water jet that the air-assisted nozzle fluid cap of internal-mixing produces mixes in nozzle interior with the high velocity air of introducing, and water jet is broken for little water droplet under the Aerodynamic force action of high velocity air and forms spraying, and water is gentle to influence each other.The restrictive condition of this types of nozzles is hydraulic pressure Pw=0 and air pressure Pa=Pmax, namely all can not form spraying when hydraulic pressure Pw=0 and air pressure Pa=Pmax, therefore hydraulic pressure Pw level off to 0 or air pressure Pa level off to maximum Pmax time MVD level off to 0.Assume the form of pressure to set up MVD relational expression, as follows
M V D = KP w m ( P m a x - P a ) n - - - ( 1 )
(1) in formula, Pmax is the air pressure maximum conditions that can set up, different nozzle arrangements, its occurrence is by testing acquisition, and K, m and n are constant, and it is carried out least square fitting acquisition by the MVD obtained with experiment measuring after formula (1) linearized process.
Therefore, the present invention is based on the spraying water droplet average diameter Method of fast estimating of nozzle kinetic parameter, it is only necessary to obtain NDPs, quickly spraying drop diameter can be estimated, specifically comprise the following steps that
S1, the acquisition hydraulic pressure value Pw at nozzle place, atmospheric pressure value Pa and described nozzle place can form air pressure maximum Pmax during spraying；
S2, pass through formulaEstimate the average diameter MVD of described spraying water droplet.
The present invention, based on the spraying water droplet average diameter Method of fast estimating of nozzle kinetic parameter, has the advantages that
Input parameter is few, it is simple to calculate process；
Calculating error is little, engineer applied is worth height；
Can require to choose suitable nozzle kinetic parameter according to water droplet average diameter, while accomplishing to shorten debugging cycle, more economical and energy saving.
Accompanying drawing explanation
Fig. 1 is the present invention comparison schematic diagram based on actual measurement MVD and the MVD calculated by formula of a preferred embodiment of the spraying water droplet average diameter Method of fast estimating of nozzle kinetic parameter.
Detailed description of the invention
For making purpose of the invention process, technical scheme and advantage clearly, below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is further described in more detail.In the accompanying drawings, same or similar label represents same or similar element or has the element of same or like function from start to finish.Described embodiment is a part of embodiment of the present invention, rather than whole embodiments.The embodiment described below with reference to accompanying drawing is illustrative of, it is intended to is used for explaining the present invention, and is not considered as limiting the invention.Based on the embodiment in the present invention, the every other embodiment that those of ordinary skill in the art obtain under not making creative work premise, broadly fall into the scope of protection of the invention.Below in conjunction with accompanying drawing, embodiments of the invention are described in detail.
In describing the invention; it will be appreciated that; term " orientation or the position relationship of the instruction such as " center ", " longitudinal direction ", " transverse direction ", "front", "rear", "left", "right", " vertically ", " level ", " top ", " end " " interior ", " outward " be based on orientation shown in the drawings or position relationship; be for only for ease of the description present invention and simplifying and describe; rather than instruction or imply indication device or element must have specific orientation, with specific azimuth configuration and operation, therefore it is not intended that limiting the scope of the invention.
The present invention focuses primarily on the spraying water droplet distribution of sizes near nozzle outlet area, sets up a kind of water droplet average diameter (MVD) estimation equation based on nozzle kinetic parameter (NDPs), helps the debugging of ground icing Experimental Establishment cloud parameter.
The water jet that the air-assisted nozzle fluid cap of internal-mixing produces mixes in nozzle interior with the high velocity air of introducing, and water jet is broken for little water droplet under the Aerodynamic force action of high velocity air and forms spraying, and water is gentle to influence each other.The restrictive condition of this types of nozzles is hydraulic pressure Pw=0 and air pressure Pa=Pmax, namely all can not form spraying when hydraulic pressure Pw=0 and air pressure Pa=Pmax, therefore hydraulic pressure Pw level off to 0 or air pressure Pa level off to maximum Pmax time MVD level off to 0.Assume the form of pressure to set up MVD relational expression, as follows
M V D = KP w m ( P m a x - P a ) n - - - ( 1 )
In formula, Pmax is the air pressure maximum conditions that can set up, and is about 6.0 × 105N/m2(nozzle arrangements provided with next section in the present embodiment carries out experiment and obtains, it will be understood that different nozzle arrangements, through the Pmax value meeting slightly deviation that experiment obtains).K, m and n are constant, depend on that nozzle arrangements designs, concrete, first formula (1) are carried out linearization process, and the MVD then obtained with experiment measuring carries out least square fitting, it is determined that the constant K in formula (1), m and n value.In the present embodiment, give a concrete nozzle, structural parameters following (actual experiment process, without considering structural parameters, gives the purpose of these structural parameters, is only in the follow-up reference that the formula (1) with design parameter value carries out directly use).
The air-assisted nozzle of internal-mixing includes liquid cap, air cap and retainer ring three part, is stainless steel, and its physical dimension is: liquid pores internal diameter dL,in=0.5 × 10-3m；Liquid pores outside diameter dL,out=1.27 × 10-3m；Nozzle air cap outlet diameter dA=1.52 × 10-3m；Atomizing space compression ring height b=(dA-dL,out)/2=0.125 × 10-3m；Air enters the sectional area A of mixing chamberm=0.548 × 10-6m2。
Water and dry air physical property (under normal atmosphere, 20 DEG C of conditions of ambient temperature) are as follows: water density ρw=998.2kg/m3；Water viscosity μw=1.0087 × 10-3kg/(ms)；Water surface tension σ=72.75 × 10-3N/m；Atmospheric density ρa=1.205kg/m3。
Simultaneously for requiring over experiment to determine parameter K, m and n, necessarily giving the range of application with hydraulic pressure, air pressure, in the present embodiment, this pressure limit is: hydraulic pressure 0.7 × 105N/m2< Pw < 4.0 × 105N/m2, air pressure 0.7 × 105N/m2< Pa < 4.5 × 105N/m2, the pressure reduction-0.8 × 10 of hydraulic pressure and air pressure5N/m2<δP<1.2×105N/m2, it should be noted that pressure reduction δ P have to be larger than its minima otherwise will not form water jet.
By above-mentioned qualifications, record MVDexp and calculated MVDcal according to experiment and carry out least square fitting, parameter K (the unit m obtained3/ N) be 1.002 × 10-10, parameter m it is 0.18, parameter n is 0.82.With reference to Fig. 1, wherein transverse axis value is MVDexp, the longitudinal axis is MVDcal, number ratios is consistent, 1:1 as shown by dashed lines, circle in the interval that thus transverse axis and the longitudinal axis are formed represents once tests, such as, a circle in the most lower left corner in this figure, represent in this experiment, the actual water droplet average diameter obtained of measuring is 20um, and calculating, by formula (1), the water droplet average diameter obtained is 18um, therefore, it is positioned at the top of dotted line, it is further to note that, article two, what solid line represented is with dotted line for benchmark, the value of fluctuation 10% up and down, can clearly be found out by this figure, the error of the MVD calculated by formula (1) is substantially within 10%, specific experiment result is as shown in table 1.
Table 1 calculates the comparison of MVDcal and experiment MVDexp
Pw(105N/m2) Pa(105N/m2) MVDexp/μm MVDcal/μm Error/%
0.7 0.7 47.1 36.89 -21.7
0.7 1.0 37.4 35.17 -6.0
1.5 1.4 42 37.67 -10.3
1.5 1.8 34.4 34.96 1.6
1.5 2.1 29.7 32.90 10.8
2.0 1.7 40.7 37.54 -7.8
2.0 2.0 35.6 35.38 -0.6
2.0 2.2 34.4 33.92 -1.4
2.0 2.8 28.5 29.46 3.4
3.0 2.2 44.6 36.49 -18.2
3.0 2.8 35.8 31.69 -11.5
3.0 3.0 31.8 30.06 -5.5
3.0 3.4 30.3 26.73 -11.8
4.0 2.8 35.9 33.38 -7.0
4.0 3.4 27.4 28.15 2.7
4.0 4.0 22.4 22.70 1.4
4.0 4.5 19.8 17.93 -9.4
As can be seen from Table 1, adopting the maximum error that formula (1) calculates MVD is 21.7%, and mean error is 7.7%.Mean error is lower than 10% magnitude, and major part experimental data is all in ± 10% error burst, sees Fig. 1.Therefore formula (1) can provide the MVD estimated value higher than the estimation equation accuracy of prior art, and can calculate MVD, convenient engineer applied rapidly according to NDPs.
Compared with prior art have the advantage that or good effect
Spraying water droplet average diameter evaluation method based on nozzle kinetic parameter has the advantage that
Input parameter is few, it is simple to calculate process；
Calculating error is little, engineer applied is worth height；
Can require to choose suitable nozzle kinetic parameter according to water droplet average diameter, while accomplishing to shorten debugging cycle, more economical and energy saving.
Last it is noted that above example is only in order to illustrate technical scheme, it is not intended to limit.Although the present invention being described in detail with reference to previous embodiment, it will be understood by those within the art that: the technical scheme described in foregoing embodiments still can be modified by it, or wherein portion of techniques feature is carried out equivalent replacement；And these amendments or replacement, do not make the essence of appropriate technical solution depart from the spirit and scope of various embodiments of the present invention technical scheme.

Claims (2)

1. the spraying water droplet average diameter Method of fast estimating based on nozzle kinetic parameter, it is characterised in that including:
S1, the acquisition hydraulic pressure value Pw at nozzle place, atmospheric pressure value Pa and described nozzle place can form air pressure maximum Pmax during spraying；
S2, pass through formulaEstimating the average diameter MVD of described spraying water droplet, wherein, K, m and n are constant, and it is by formulaThe MVD obtained with experiment measuring after linearized process carries out least square fitting acquisition.
2. the spraying water droplet average diameter Method of fast estimating based on nozzle kinetic parameter as claimed in claim 1, it is characterised in that: to different nozzle arrangements, enough air pressure maximum Pmax formed when spraying at described nozzle place are by testing acquisition.
CN201610114874.9A 2016-03-01 2016-03-01 Rapid mist spray water drop average diameter estimation method based on nozzle power parameters Pending CN105728229A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112844895A (en) * 2021-01-03 2021-05-28 清华大学 Device for controlling liquid jet flow crushing
CN113252281A (en) * 2021-06-02 2021-08-13 中国空气动力研究与发展中心低速空气动力研究所 Method for reconstructing size distribution of icing cloud droplets

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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CN102494622A (en) * 2011-12-09 2012-06-13 北京航空航天大学 Water drop diameter measuring method
CN104117447A (en) * 2013-04-24 2014-10-29 武汉航空仪表有限责任公司 Spraying parameter control method for icing test

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101814115A (en) * 2010-03-19 2010-08-25 中国计量学院 Method for forecasting axial evolution trend of average atomizing particle size of bubble-like atomizing nozzle
CN102494622A (en) * 2011-12-09 2012-06-13 北京航空航天大学 Water drop diameter measuring method
CN104117447A (en) * 2013-04-24 2014-10-29 武汉航空仪表有限责任公司 Spraying parameter control method for icing test

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Title
唐虎，常士楠，成竹，等: "内混式空气助力喷嘴喷雾水滴尺寸分布建模", 《航空学报》 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112844895A (en) * 2021-01-03 2021-05-28 清华大学 Device for controlling liquid jet flow crushing
CN113252281A (en) * 2021-06-02 2021-08-13 中国空气动力研究与发展中心低速空气动力研究所 Method for reconstructing size distribution of icing cloud droplets

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