A kind of nozzle for minisize gas-turbine combustor
Technical field
The present invention relates to the gas turbine technology field, is a kind of small scale liquid fuel atomization nozzle of the 100kW of being exclusively used in level miniature gas turbine combustion chamber.
Background technology
Miniature gas turbine is one of major impetus of distributed power generation, distributed energy supply, and its power generally adopts the backheat circulation generally below hundreds of kilowatts, generating efficiency can reach 30% or higher, have compact conformation, volume is little, efficient height and reliability advantages of higher.The combustion chamber is one of critical piece of miniature gas turbine.
Fuel atomizer is one of vitals of combustion chamber, and the quality of its performance is directly connected to the performance and the life-span of whole combustion chamber.For guaranteeing the startup and the off design performance of normal operation in combustion chamber and unit, usually require fuel nozzle can in a wider load scope, guarantee promptly to require the fuel oil drop that a good atomized particle size and suitable atomization angle are arranged by good atomization quality.Gas-turbine combustion chamber generally adopted rotarytype injector to realize fuel-oil atmozation in the past, and the mist of oil liquid-drop diameter that is produced is between 50 to 400 μ m.In the pressure atomization technology, utilize oil pump to give atomizer with after the fuel oil pressurization, in centrifugal force and the capillary interaction of fuel oil, oil film is torn into little oil droplet, from nozzle, spray, form the mist of oil of conical distribution, thereby finish whole atomization process.Because the restriction of rotarytype injector performance might bring following problem if directly use on miniature gas turbine combustion chamber:
1. because the atomization quality of the centrifugal spraying nozzle of single oil circuit is bigger with import oil pressure (fuel flow) variation, can't satisfy the atomization of miniature gas turbine unit under startup and declared working condition and variable working condition simultaneously.
2. for to reach good atomization, the needed import oil pressure of rotarytype injector is higher, and this will bring hidden danger to the safety and the stability of unit, has also increased the manufacturing and the operating cost of whole unit pipeline simultaneously.
3. because the centrifugal spraying spray nozzle front end is in the high-temperature region of combustion chamber, do not have special cooling technology, cause nozzle to burn out easily.Simultaneously, the possible coking of fuel oil, thereby plug nozzle.
4. because centrifugal spraying spray nozzle front end oil mist concentration is higher, the oxygen content relative deficiency causes oil inflame insufficient, is easy to generate phenomenons such as smoking of the exhaust.
In the heavy duty gas turbine combustion chamber, adopted pneumatic nozzle to solve this problem in the past, but for miniature gas turbine, because physical dimension reduces greatly, fuel flow reduces, jet size reduces greatly, therefore, is necessary the atomizer of combustion chamber is done further improvement, make miniature gas turbine combustion chamber under various operating conditions, can both obtain rational atomized particle size and distribute, make whole combustion chamber can satisfy the requirement of high-efficient low polluting combustion technology.
Summary of the invention
The purpose of this invention is to provide a small scale nozzle that is applicable to the miniature gas turbine combustion chamber of 100kW level, no matter this nozzle is that operation can both obtain good atomizing effect under unit starting or declared working condition.
For achieving the above object, technical scheme of the present invention is achieved in that
A kind of nozzle for minisize gas-turbine combustor is provided, and is the small size liquid fuel nozzle that is used for 100kW level miniature gas turbine combustion chamber, and it is with liquid fuel atomization; It comprises that fuel path (1), annular gas channel (2) and burner root wind spray into passage (3) three parts, fuel path (1) is a stainless steel tube, front end and built-in centrifugal atomization apparatus (6) interference fit, the inwall interference fit of the interior endless tube (9) of outer wall and annular gas channel (2); The outer endless tube outer wall of annular gas channel (2) is nozzle outside wall surface (4), outside wall surface (4) near jet expansion gradually projection extend into round table-like burner root (5), evenly be provided with most air on this burner root (5) and spray into passage (3), this air duct (3) is used to provide the air that replenishes atomizing and cooling;
Annular gas channel (2) is the atomizing air passage, wherein is provided with axial swirler (7), and the outlet of annular gas channel (2) is annular reducing (8), and annular reducing (8) is looped around the Zhou Yuan of nozzle spout (11);
Fuel path (1), annular gas channel (2) and round table-like burner root (5) are axially symmetric structure and shared same axis, being centered close on this axis of nozzle spout (11);
Nozzle outside wall surface (4) diameter is not more than 15mm, and round table-like burner root (5) outer diameter is not more than 25mm.
Described nozzle, its described built-in centrifugal atomization apparatus (6), structure are the centrifugal spraying nozzle of a routine, the optkmal characteristics parameter by selecting this rotarytype injector and spin chamber's structure and size reach best atomizing effect.The optkmal characteristics parameter area of this nozzle is 1.8~2.5.
Described nozzle, its described axial swirler (7), its periphery circular surfaces are provided with most equally distributed air ducts, and air duct is rectangular coil groove (10), and this rectangular coil groove (10) unfolded surface line angle degree is 55 °~65 °.
Described nozzle, its described annular reducing (8) is an annular convergent mouth, and this reducing is calculated according to aerodynamics, and its discharge area reaches the desired critical area of local velocity of sound just.
Described nozzle, its described round table-like burner root (5) is provided with most air and sprays into passage (3), it is one group of 8~12 along the circumferential direction equally distributed circular hole that this majority air sprays into passage (3), is positioned at the periphery circle of annular convergent spout (8); This circular hole is pressed the certain orientation rotation, angle between circular hole axis and the nozzle-axis is projected as 42 °~48 ° on front view, be projected as 20 °~25 ° on vertical view, its eddy flow direction is opposite with the eddy flow direction of atomizing air by the axial swirler (7) arranged in the annular gas channel (2).
Described nozzle, the mechanical stitch molding mode is adopted in its nozzle arrangements assembling, to guarantee the air-tightness and the concentricity of nozzle, guarantee that simultaneously nozzle spout (11) has certain circularity and guarantees that nozzle-axis is vertical with nozzle spout (11) exit face, and satisfy the fineness requirement.
Described nozzle, its described majority equally distributed rectangular coil groove shape air duct is three.
The invention has the advantages that: do not increasing the nozzle manufacturing cost, adopting under the prerequisite of conventional processing method,, in the space of small scale so, realizing the high-efficient atomizing of fuel oil by optimal design.Can utilize the nozzle of a small scale to satisfy miniature gas turbine combustion chamber requirement to the fuel-oil atmozation quality under different load conditions, thereby make the structure of combustion chamber more compact.Its reason is in example of the present invention, and the high speed rotary air is to the shearing force of oil film if the perturbation action of broken oil film is advocated, but not the surface tension of oil film itself, therefore along with the variation of fuel flow, the atomizing effect of nozzle of the present invention is constant substantially.
Further advantage of the present invention is to obtain with respect to the better atomization quality of rotarytype injector.Its reason is in example of the present invention, and by introducing small air pump, the nozzle atomization air further pressurizes, and the convergent spout that utilizes annular atomizing air passage then accelerates to atomizing air and reaches or near local velocity of sound.Increase the increase of relative velocity between atomizing air and the fuel oil oil film (mist), strengthened the mutual shear action between flow of atomization air and fuel oil oil film or the droplet, thereby improved the atomization quality of fuel oil.And, in the miniature gas turbine combustion chamber that example of the present invention was suitable for, because fuel oil and atomizing air consumption all are significantly less than conventional heavy duty gas turbine unit, therefore, the introducing of atomizing air can't bring very high cost input, only needs a small air pump to get final product.
The further advantage of the present invention is to reduce greatly that nozzle burns out and because of the probability of happening of the fault of the normal operation of serious threat units such as fuel oil high-temperature-coked plug nozzle, prolonged the overhaul time interval, has reduced the maintenance and the operating cost of unit.Its reason is because fuel droplet has two-way low-temperature and high-speed air stream outward, when promoting fuel-oil atmozation, has also strengthened the heat-sinking capability of fuel nozzle, greatly reduces the temperature of nozzle head and nozzle exit.And because the backflow of air-flow at this place eliminated in the increase of air mass flow, the mist of oil that produces is transported in the combustion zone in time, and the air that needs of postinjector root burning, thereby reduce the probability that high-temperature-coked takes place fuel oil near jet expansion.
Further advantage of the present invention can make the fuel oil can more complete burn cleanly in the combustion chamber, has improved the whole efficiency of combustion chamber, and has reduced the discharging of air pollutants such as smoldering to a certain extent.This is because of higher in jet expansion position fuel oil concentration, is a relative anoxic environment herein.Burner root cooling air and atomizing air enter the combustion chamber by nozzle, have strengthened the premix of fuel oil mist of oil and air combustion chamber the on the one hand, and the peak temperature of reduction flame combustion chamber suppressed the generation of NOx in the combustion chamber; On the other hand because the replenishing of additional air, increased the oxygen concentration of this position, thereby it is more complete that oil inflame is got, and improved the efficiency of combustion of combustion chamber, and effectively reduce that exhaust combustion chamber is smoldered and the generation concentration of CO, improved the environmental-protecting performance of unit greatly.
Description of drawings
The axial cutaway view of a kind of nozzle for minisize gas-turbine combustor of Fig. 1 the present invention;
Fig. 2 atomizing air passage of the present invention axial swirler front view;
Fig. 3 nozzle head fragmentary cross-sectional view of the present invention;
Fig. 4 is equipped with the combustion chamber connection diagram of a kind of nozzle for minisize gas-turbine combustor of the present invention;
Fig. 5 uses the atomization characteristics curve that a kind of nozzle for minisize gas-turbine combustor of the present invention obtains.
The specific embodiment
Fig. 1 to Fig. 4 is specific embodiments of the invention.
With reference to shown in Figure 1, a kind of nozzle for minisize gas-turbine combustor A, be the small size nozzle that is used for 100kW level miniature gas turbine combustion chamber, by fuel path 1, the annular gas channel 2 of atomizing air is provided and replenishes atomizing and the burner root wind of cooling air sprays into passage 3 three parts and forms.Nozzle A outside wall surface 4 diameters are not more than 15mm, and the outer diameter of round table-like burner root 5 is not more than 25mm.Do not increasing nozzle A manufacturing cost, adopting under the prerequisite of conventional processing method,, in the space of small scale so, realizing the high-efficient atomizing of fuel oil by optimal design.Wherein, oil circuit 1 is provided with built-in centrifugal atomization apparatus 6, provides the annular gas channel 2 of atomizing air to be provided with axial swirler 7, before the atomizing air ejection, is provided with annular reducing 8.The petroleum pipeline of this nozzle A is a stainless steel tube, front end and built-in centrifugal atomization apparatus 6 interference fit, the inwall interference fit of the interior endless tube 9 of outer wall and annular gas channel 2.The built-in centrifugal atomization apparatus 6 of this nozzle A, structure are the centrifugal spraying nozzle of a routine, and the optkmal characteristics parameter by selecting this rotarytype injector and spin chamber's structure and size reach best atomizing effect.The scope of these structural parameters is 1.8~2.5.
Shown in seeing figures.1.and.2, the atomizing air passage 2 of this nozzle A is a circular passage, and the outer endless tube outer wall of this circular passage is a nozzle outside wall surface 4, the petroleum pipeline outer wall interference fit of interior endless tube 9 inwalls and oil circuit 1.Atomizing air enters annular gas channel 2 backs earlier through axial swirler 7, again by annular reducing 8 ejections.The atomizing air passage of this axial swirler 7 is three equally distributed rectangular coil grooves 10, these rectangular coil groove 10 unfolded surface line angle degree are 55 °~65 °, in annular gas channel 2, can not need precision machined swirl vane like this, the eddy flow effect that also can obtain.Before atomizing air was sent from the outlet of annular gas channel 2, by an annular reducing 8, this was an annular convergent mouth, and this annular reducing 8 is calculated according to aerodynamics, and its discharge area reaches the desired critical area of local velocity of sound just.
With reference to Fig. 1 and shown in Figure 3, it is one group of 8~12 along the circumferential direction equally distributed circular hole that the root wind that is provided with on the round table-like burner root 5 sprays into passage 3, be positioned at the periphery circle of annular convergent spout 8, this circular hole is pressed the certain orientation rotation, angle between the axis of circular hole and the nozzle A axis is projected as 42 °~48 ° on front view, be projected as 20 °~25 ° on vertical view, its eddy flow direction is opposite with atomizing air eddy flow direction.The existence of this root wind, when promoting fuel-oil atmozation, also strengthened the heat-sinking capability of fuel nozzle, greatly reduce the temperature in nozzle A head and nozzle A exit, can reduce greatly that nozzle A burns out and because of the probability of happening of the fault of the normal operation of serious threat units such as fuel oil high-temperature-coked plug nozzle A, prolong the overhaul time interval, reduced the maintenance and the operating cost of unit.
With reference to shown in Figure 1, the mechanical stitch molding mode is adopted in the assembling of this nozzle A structure, to guarantee air-tightness and the concentricity of nozzle A, guarantee that simultaneously nozzle spout 11 has certain circularity and guarantees that nozzle-axis is vertical with nozzle spout 11 exit faces, and satisfy certain fineness requirement.
With reference to shown in Figure 4, this figure is the combustion chamber connection diagram that nozzle of the present invention is installed, the gas of the atomizing air of nozzle A and burner root cooling air is all from the compressor 12 of gas turbine unit, the cooling air that root wind sprays in the passage 3 is directly supplied with by compressor 12 outlet sources of the gas, and the atomizing air in the annular gas channel 2 is supplied with by additional small air pump 13 pressurization backs.Fuel path 1 is communicated with oil pump 14, obtains fuel oil.More than connect and carry out routinely.
With reference to shown in Figure 5, this figure uses one group of spray characteristics curve that nozzle A of the present invention obtains.Fuel oil enters nozzle A petroleum pipeline through gear oil pump 14, and in the applied combustion chamber of the present invention, nozzle A atomizing effect is good, the SMD of fuel-oil atmozation is about 28 μ m, and the load regulation range broad, can reach 1: 6 adjustable range, fuel-oil atmozation cone angle excursion is 45 °~65 °.
The root wind of nozzle of the present invention sprays into the existence of cooling air in the passage 3, when promoting fuel-oil atmozation, also strengthened the heat-sinking capability of fuel nozzle, greatly reduce the temperature of nozzle head and nozzle exit, can reduce greatly that nozzle burns out and because of the probability of happening of the fault of the normal operation of serious threat units such as fuel oil high-temperature-coked plug nozzle, prolong the overhaul time interval, reduced the maintenance and the operating cost of unit.
Nozzle of the present invention, in structural design, its spin chamber, fuel gallery head is reserved one section appropriate length, weld with spout after adopting roll forming subsequently, to guarantee the air-tightness and the concentricity of nozzle, to guarantee that simultaneously the nozzle spout has certain circularity and guarantees that its axis is vertical with the jet expansion face, and satisfy certain fineness requirement.
The centrifugal atomizing process of small scale nozzle of the present invention is achieved in that fuel oil enters and manages the fuel gallery in the nozzle after oil pump pressurization, radially entering annular chamber near the head place through four vertical holes, fuel oil is via six spin chambers of constituting of the conduit of deflection radially subsequently, and the speed that obtains certain axial velocity and circumferencial direction is after the spout outflow.The fuel oil that nozzle bore flows out forms the open circles taper oil film of rotation because of strong eddy flow, and under the surface tension effects of centrifugal force and fuel oil self oil film is torn into little oil droplet, thereby finishes the preliminary atomization process of nozzle of the present invention.
The pneumatic nebulization process of small scale nozzle of the present invention is achieved in that air enters the circular passage of nozzle by the air pump pressurization, at the axial swirler that constitutes by three rectangular coil groove passages near head place process, after obtaining suitable swirl strength, enter that annular convergent jet pipe accelerates to or spray near behind the local velocity of sound.High speed rotary air and fuel oil oil film meet, and strong shear action takes place, and reach better atomizing effect, thereby finish whole fuel-oil atmozation process.
More than by the specific embodiment the present invention is described in detail, in conjunction with the accompanying drawing of being given, this structure is done slightly to change and also be can be used for other ground combustion machine, aeroengine combustor buring chamber, and the usefulness of other liquid injection.Nozzle of the present invention also is applicable to and sprays heavy oil and various chemical industry lyosol.These distortion and modification, and the specific embodiment that adopts different fuel combustions all should drop within the scope that claim of the present invention protects.