FR2556412A1 - METHOD AND APPARATUS FOR DEGRADING AN ANTI-MIST FUEL - Google Patents

Abstract

THE INVENTION RELATES TO A PROCESS AND AN APPARATUS FOR DEGRADING AN ANTI-MIST FUEL (THAT IS TO SAY WHICH CONTAINS AN ADDITIVE WHICH PREVENTS THE FORMATION OF MIST BY THE FUEL WHEN AN ACCIDENT CAUSES A FUEL LEAK) IN ORDER TO GIVE IT ALL THE PROPERTIES OF NON-ANTI-MIST FUEL. ACCORDING TO THE INVENTION, THE FUEL IS FLOWED UNDER PRESSURE THROUGH AT LEAST ONE ORIFICE 45 WHICH CAUSES A PRESSURE DROP AND ACCELERATION OF THE FUEL WHICH CAUSES THE RUPTURE OF THE ADDITIVE MOLECULES AND RETURNS TO THE BRISPRIANT FUEL. ADVANTAGEALLY, THE APPLIANCE CONTAINS A SERIES OF ORIFICES AND MEANS75 ARE PROVIDED TO ALLOW SOME OF THE ORIFICES TO BE SELECTIVELY CLOSED IN ORDER TO ADJUST THE FLOW OF FUEL FLOWING THROUGH THE APPLIANCE.

Description

The present invention relates to a method and to

  an apparatus for degrading an anti-misting fuel.

  It is well known that aviation fuel of the kerosene type, such as Jet-A, is less flammable than fuel of the gasoline type with regard to ignition.

  fuel vapor. However, when landing

  wise accidental wind shear forces at high speed can cause the formation of either fuel (kerosene or petrol) of a highly flammable mist. An ignition source, such as

  spark or hot engine part, can easily ignite

  sea this fog. To solve this problem, we developed a type of fuel called anti-fogging kerosene (AMK). AMK fuel is produced by adding a small amount of a specific additive (typically less than

  0.3% by weight) with kerosene fuel (Jet-A).

  One such additive is the FM-9 fuel modifier obtainable from Imperial Chemical

  Industries, Great Britain. This additive modifies the combustion

  target so that it forms globules rather than a fine mist under the action of wind shear or

  of another atomizing influence. Apart from its characteristics

  anti-misting properties, AMK fuel resembles

Jet-A fuel.

  However, since the AMK fuel does not deteriorate

  does not put on easily and does not easily form a fog

  lard, it presents a problem when igniting the combustion chamber of the jet engine. In addition, the

  AMK fuel has non-New flow characteristics

  that have harmful effects on performance

  engine flow meter and heat exchanger. When-

  As AMK fuel flows at high speed through the micrometric mesh fuel filter of the engine, it tends to form a gel on the filter, which leads to clogging of the filter. To avoid these problems, it is necessary to degrade the AMK fuel, that is to say to give the fuel the behavior of Jet-A fuel, in the engine fuel circuit. Degradation is a process that involves transforming the molecular structure of the additive into a new form

  which has practically no influence on the characteristics

  fog-forming ticks or other behavior of the

Jet-A fuel.

  The present invention relates to a method and an app-

  same to carry out the degradation process.

  The present invention thus aims: - to produce a new improved device for degrading an anti-fogging fuel;

  - to make a new and improved device for

  grade an anti-fogging fuel for jet aircraft;

  - to make a new and improved device for

  grade an anti-fogging fuel that uses tech-

  construction mistletoes allow it to fulfill the function

  desired throttle tion of the fuel system

  reaction tor, in addition to the degradation function.

  In one embodiment of the present invention,

  an anti-misting fuel to which we have previously added

  tee an additive in order to reduce the formation of fog and, therefore, pocket its ignition is accelerated through an opening so as to degrade the fuel so that its fog-forming characteristics

  more like those of a fuel that does not

not hold such an additive.

  The rest of the description refers to the figures an-

  which represent respectively: Fig. 1: a first embodiment of the apparatus of the present invention; Fig. 2: a type of crosslinked structure being treated by the apparatus of the present invention; Fig. 3: a second type of reticulated structure contained in a conduit: FIG. 4: a second embodiment of the apparatus of the present invention: FIG. 5: a sectional view of the embodiment of Fig.4; Fig. 6 and 7: the acceleration of a particle around two types of angles; Fig. 8: a third embodiment of the apparatus of the present invention; Fig. 9: a fourth embodiment of the apparatus of the present invention: FIG. 10: a sectional view of the embodiment of FIG. 9 ,, in the assembled state; Fig. 11: a cylindrical coordinate system; Fig. 12: the positioning of the openings of the present invention with reference to the coordinate system of FIG. 11; Fig. 13: a valve opening of the prior art; Fig. 14: the opening-stroke curve of the type obtained with fuel valves; Fig. 15: a simplified embodiment of the apparatus of FIG. 10;

  Fig. 16: two types of fluid jets which strike an over-

  face. Fig. 1 shows a high pressure fuel pump 3 similar to that used on a gas turbine engine of a commercial aircraft. The type of pump is of no importance for the invention provided that it produces

  an increase in fuel pressure. A channel-

  tion 6 of fuel located downstream of the pump 3 contains

  an apparatus according to an embodiment of the present in-

  vention. We drew theFig. 1 in an exaggerated and highly schematic form to facilitate the explanation. The direction of flow of the fuel is represented by an arrow 12. A partition obstructs the flow of the fuel but has a perforation 18 through which the fuel can flow. A pressure drop in the fuel, which is

  produced by the perforation 18 of the partition 15, has been shown

  sensed by the symbol at P. The fuel which is accelerated

  is the one located in the upstream region 21 and this

  bustible is of the anti-misting type.

  Anti-fogging fuel, when it is made up

  by jet-A kerosene and the fuel modifier

  FM-9 target in a concentration of about 0.3% by weight,

  has the suppression characteristics of the forma-

  tion of a fuel mist. The plaintiff does not

  is not the precise mechanism of the behavior of the modification

  of the FM-9 fuel. The plaintiff, however, is

  aware of indications that the modifier is

  sout in solution in kerosene. Combustion properties-

  non-misting anti-fog target are imparted to kerosene

  with long chain or molecular structure polymers

  similar area contained in the additive FM-9. The precise mechanism by which this occurs is not known to the applicant, but it can be assumed that two mechanisms

at least come into play.

  First, the polymers can be cross-linked with each other, as shown in FIG. 2, so that a net skeleton is formed which traps the fuel in cells 27. Secondly, the polymers can form an entanglement 30 as shown in FIG. 3, the forces opposing the formation of fog being those which result from the close proximity of neighboring molecules of fuel and polymer. Such forces can include electrostatic and ionic forces and van der Walls' interactions. These forces would link

  polymers and fuel into a system with pro-

  properties somewhat similar to those of a

  glass fibers embedded in an epoxy resin material.

  In addition, other types of arrangements may occur.

  additive polymers. For simplicity, we use

  here will be the term "crosslinked" to refer to the layout

  of polymer whatever the mechanism by which the

tible is linked.

  Despite the lack of detailed knowledge about

  nant the particular structure formed by polymers

  additives, we know that polymers communicate with combustion

  tible in the undegraded state a quality which reduces the tension

  dance of the fuel to form a mist.

  As indicated above, the non-degraded fuel (that is to say anti-misting) is rapidly accelerated in the perforation 18. This acceleration imposes elongation stresses on the chains 24 of the polymer, as represented by the elongated chain 33 on Fig. 2. Constraints

  lengthen many of the broken chains

  ments, such as fragment 36. Following the acceleration in the perforation 18, the fuel (now degraded) is expelled into a downstream cavity 39. The fuel decelerates

  in the downstream cavity 39 and moves outward (that is

  i.e. away from the axis 57 of the perforation 18) from the perforation along the paths shown

  by arrows 42. Although it is believed that the constraint of al-

  long resulting from the rapid acceleration of the fluid either

  an important factor that contributes to the molecular fractionation

  of the anti-misting additive, the Applicant has

  further, that the fluid as a whole is subjected to a complex field of movement when it enters the perforation 18. These movements include a movement

  vortex across the full cross-section

  soil of the perforation 18 as well as turbulence of the boundary layer adjacent to the surface of the perforation 18. Therefore, an important aspect of the invention is the

  relationship between shape and area associated with the per-

  hole 18 relative to the surface of the cross-section

  dirty. Furthermore, the rupture of the additive molecules can also be attributed to the shear stress of the fluid which results in an equivalence of the elongation stress, in particular in the region in close

  proximity to the surface associated with the perforation 18.

  There is shown in FIG. 1 a single orifice 18.

  Greater degradation of the fuel additive

  tible occurs for a given cross-sectional area if the area is distributed over several openings of small diameter, such as the openings 45 formed in the partition 15 shown in FIG. 4, as opposed to a single opening 18 of larger diameter in FIG.

  1. Consequently, a second embodiment of the information

  vention involves the use of a series of openings by con-

  traste using a single opening. In other words, in order to obtain a given pressure drop and flow rate, the necessary cross-sectional area can be obtained by means of a single orifice, as shown in FIG. 1, or by means of a series of orifices as shown in the

Fig. 4.

  A widely accepted formula for describing the relationship between flow (Q), pressure drop (AP) and flow section (A) is: Q (m3 / s) = A Cd VI

  formula in which the loss coefficient Cd is essential

  the same for similar geometry holes.

  For a circular hole, section A is given by the formula:

A = - D2

  where D is the diameter of the hole. The area (S) of a hole is: S = 7 Dt in which D is the thickness or length of the surface

  of the hole in the flow direction. We have indicated the

  area S in Fig. 4 and the dimension t in FIG. 5.

  If N represents a number of holes of the same diameter, D, we obtain: A = N T D2 or D = g and S = NTrDt = tV4 TAN For the same flow rate and the same pressure drop AP, the

  total section A and the thickness t are the same, therefore

  quent, the total area S is proportional to Air, the square root of the number of holes. For example, four holes

  circular having the same cross-sectional area to-

  tale that a single hole have an area (S) equal to double

  that of the single hole. As previously indicated, the de-

  dimming of the anti-fogging fuel is improved by a

  increase in surface area (S) across

  which the fluid is accelerated. Therefore, a mode of reaction

  The invention consists in using a series of holes or orifices to obtain the same total flow for a given available pressure drop. The use of a larger number of holes also has the effect of obtaining greater uniformity in the acceleration of the fluid since the diameter of each hole is smaller and that, consequently, the fluid has less opportunity to pass

  through the less disturbed center of the hole.

  In a third embodiment of the invention, a fuel line 6 contains a partition 15 in which are formed openings 45 constituted by cylindrical holes, each of the cylinders being aligned so that its own axis 57, FIG. 5, or approximately parallel to the axis 59 of the fuel line. The

  partition is normal, that is to say perpendicular, to the di-

  rection of fuel flow. The cylinder openings

  driques 45 intersect, therefore, the surfaces 15A of the partition at right angles, forming the angles 62 of

Fig. 6.

  This intersection at a right angle creates an opening with sharp edges, these edges being designated by the reference 65.

  will now examine an effect of these sharp edges. When-

  that a particle 68 of fuel, FIG. 6, enters the opening 45 it is thrown violently around the edge and is subjected to strong acceleration and strong turbulence. This is in contrast to the situation that would occur with an opening with a rounded edge, such as that shown in FIG. 7. As shown in this

  figure, the fuel particle 68A which moves next

  before path 66A is subject to acceleration and

  less turbulence. Therefore, it is preferred-

  map that the flow path defined by the surface of the partition 15 and the opening 45 has a change

  abrupt around a sharp edge, such as the change of di-

  section at 90 shown in FIG. 6.

  In a fourth embodiment of the present invention, the total area of the cross sections of the orifices 45 through which the fuel can flow is

  controlled by a register plate 75, Fig. 8, which

  smooth in the direction of the arrows 77 and 79 relative to the partition 15 so as to cover and selectively uncover the openings 45 so as to thereby change the section

  of total transverse surface of the orifices 45 which is or

  green at fuel flow. In this way, it is possible to vary the flow rate, as well as the pressure drop, through the partition, thereby varying the acceleration of the fuel which, in turn, varies the importance

  constraints applied to networks of poly- chains

  crosslinked mother 24, Fig. 2, thereby varying the de-

  extent of degradation suffered by the anti-fogging fuel.

  An exploded view is shown in FIG. 9 and a

  sectional view in FIG. 10 of a fifth embodiment

  tion of the present invention. Anti-mist fuel

  health (represented by arrows 87) enters a cavi-

  upstream tee 88, is accelerated through holes 72 and decelerated

  re in a cavity before 94 and from there it is routed to

  than to the motor (not shown) by a conduit 95. The cavity

  downstream 94 serves as manifold for the fuel.

  The downstream cavity 94 is delimited by an envelope which

  fits around the holes 92, Fig. 9, and the edges of which are sealingly engaged in grooves 94B. Only half of the envelope has been shown in FIG. 9 of

  which it is designated by the reference 94A.

  The lower edge 84 of a piston 86, FIG. 9, 10 and 15, defines the limit of the cavity 88.The position of the piston 86 along the axis 90 and, therefore, that of the cavity 88

  determine the number of holes that are open to the flow-

  fuel. Piston 86 is analogous to plate

of Fig. 8.

  An important aspect of the fifth embodiment is the configuration of the holes 92 with respect to their

  dimensions and their position. Fig. 11 represents a system

  teme of classical cylindrical coordinates. The position of a point in the system is given by three coordinates r, 0 and z. The positions of the holes are given in Table 1 in accordance with this cylindrical coordinate system. The cylinder 98 of FIG. 12 corresponds to the cylinder 98A of FIG. 11. The cylinder 98C of FIG. 9 corresponds to the cylinder 98 of FIG. 12.

TABLE 1

  (the coordinate r for all the holes is 33.02 mm) Hole Diameter Coordinate z Coordinate 0 n of the hole (mm) (degrees, minutes) (mm)

1 0.5588 - 0

2 0.5588 0.4572 180

3 0.5588 0.9144 90

4 0.5588 1.3716 270

5 0.5588 1.8288 0

6 0.5588 2.2860 180

7 0.5588 2.7432 90

8 0.5588 2.9972 270

9 0.5588 3.2512 0

10 1.1430 3.9116 180

it 1.1430 4.2926 36

12 1.1430 4.5466 252

13 1.1430 4.8006 108

14 1.1430 5.0546 324

15, 16 1.1430 5.4356 90, 270

17, 18 1.1430 5.8166 45, 225

19-21 1.1430 6.1214 0, 120, 240

  22-25 1.1430 6.4262 22o30 ', 112 30',

202030 ', 292.30'

  26-29 1.1430 6.9596 67 30 ', 157o30',

247030 ', 337030'

  -34 1.1430 7.3406 36, 108, 180, 252,

324

2,556,412

  1 1 Hole Diameter z coordinate 0 coordinate n of the hole (mm) (degrees, minutes) (mm)

  -39 1.1430 7.7216 0, 72, 144, 216, 288

  40-45 1.1430 8.1026 30, 90, 150, 210

270, 330

  46-51 1.1430 8.4836 45, 105, 165, 225,

2850, 345

  52-59 1.1430 8.8646 22030 ', 67030', 112030 ',

157030 ', 202030',

247030 ', 292030', 337030 '

  -67 1.1430 9.2456 11 1.5 ', 56015', 101015 ',

146o15 ', 191015',

236015 ', 281015', 326015 '

  68-75 1.1430 9.6266 33045 ', 78045', 123045 ',

168o45 ', 213o45'

258 45 ', 303045', 348 45 '

  76-83 1.1430 10.0076 45, 90, 135, 180,

225, 270, 3150, 0

  84-91 1.1430 10.3886 22030 ', 67030', 112030 ',

157030 ', 202030',

247 30 ', 292030', 337030 '

  92-99 1.1430 10.7696 11015 ', 56 15', 10115 ',

146 15 ', 191015',

236015 ', 281015', 326015 '

  -107 1.1430 11.1506 33045 ', 78045', 123045 ',

168o45 ', 213 45',

238045 ', 303045', 348045 '

  There is shown in FIG. 12 two of the holes, namely

  hole 1 and hole 6 to better illustrate their position-

  with reference to Table 1. The three coordinates (r, 0 and z) for each hole have been indicated in Fig.

  12 and it seems unnecessary to describe them further.

  The reader will note that only two hole diameters were used, namely 0.5588 mm and 1.1430 mm. This fact facilitates the fabrication of the holes by machining by electronic discharge, since only two dimensions of electrodes are required. (The holes are formed by an electrolytic reaction between the electrodes and the cylinder 98C of FIG. 9. The shape of the hole is determined by the

  shape of the electrode. In the embodiment shown

  tee, the holes are circular so it is appropriate to use cylindrical electrodes). The fact that you only need two electrodes reduces the changes

  electrodes during machining and thus saves time.

  The configuration of holes just described pro-

  gives a total cross-sectional area for the

  fuel (i.e. full opening) works

  tion of the piston position. The position of the piston is

  the distance by which the edge 84 of the piston is spaced from the po-

  sition in which this edge covers the holes having the smallest z coordinate, namely hole 1 in Table 1 and in Fig. 15. This distance is usually called the piston stroke and is shown as the dimension

101 in FIG. 15.

  A construction of the prior art of a valve

  of jet engine fuel uses a semi-piston

  connectable to piston 86 of FIG. 9 but with a single large opening 86A having the tulip shape shown in the

  Fig. 13. This prior art valve has the function

  opening-stroke 107 shown in FIG. 14. The reader will note that the derivative (of opening / of course) of the function is nonlinear and increases when the opening

  is growing. One of the reasons for this non-linearity is the de-

  to provide a fuel flow rate that is extremely sensitive to low fuel flow rates. The slope of the function 107 of FIG. 14 is relatively flat at short strokes, such as for example 2.54 mm. As a result, it does not

  produces that a small change of opening for a change-

  given stroke. This is desirable at low fuel rates which generally correspond to

  low engine speeds. Naturally, it would be desirable to

  table to get a slight slope at all points of the curve but it is obvious that a slight slope would require

  an intolerably long race to provide one or more

  green enough. The valve would be too long.

  Therefore, an increasing slope is expected as the stroke lengthens to allow the valve to be given

  suitable dimensions. The curve 108 of FIG. 14 rep-

  feel the open-stroke function associated with the valve before-

  as described and shown in Figs. 9 and 10. We no-

  tera that the curve 108 obtained by means of a series of holes provides the desired double advantage of a high sensitivity to low flow rates and a short stroke of the valve. When

* the description of the use of a series of openings for

  improve degradation while simultaneously obtaining the desired flow / pressure drop characteristics of a valve

  of jet engine, the use of circular holes has been described

  laires. However, it is not strictly necessary to use

  use circular holes and other shapes could be used, such as slots, squares or

  triangles. An important feature with regard to

  identifies the present invention is obtaining a superficial

  cie (S) increased openings for a total cross-sectional area (A) and a given pressure drop and flow. This avoids excessive pressure drop

  high and the limited range of to-

  imposed by the use of a single opening to obtain

  nir comparable degradation. The invention, on the other hand, provides the required level of degradation while retaining

  the fuel valve capacities of jet engines

tion of the prior art.

  The present invention provides acceleration of the anti-misting fuel through the holes 92 of Figs. 9, and 12 while ensuring an open-stroke function

  similar to that of the prior art valve.

  This feature virtually ensures the advantage of being able to more easily climb up onto existing aircraft with a degrading device so that these aircraft can use an anti-misting fuel. For example,

  in the case of jet engines which use a

  bypass fuel type, the bypass valve can be made in the form shown on the

  Fig. 9, thereby maintaining an essential pressure drop-

  constantly constant through the metering valve of the

  fuel demand. This arrangement would be applicable to engines which use a fuel pump with constant flow. For motors that use a valve

  throttling to maintain essential pressure drop-

  constant through a fuel metering valve

  tible, either for post-combustion or for main flow

  cipal supplied to the engine, the concept shown in FIG. 9

  is also applicable. This arrangement can also be

  used when a fuel pump is used

centrifugal tent on the motor.

  The fifth embodiment has been described in detail.

  referring to the use of particular dimensions. Naturally, when using the device in different motors

  or for different valves, it will be necessary to use

  be different fuel valves with functions

different opening-race.

  The present invention provides a greater advantage.

  new, in addition to the degradation of the combustion

  tible, namely the reduction of valve erosion. The RO-

  sion occurs when high speed fuel strikes surface 150, Fig. 9. Shocks tend to erode the surface 150. However, the erosion is less with the multiplicity of holes 92 in FIG. 9 that when

  uses the single opening 86A in FIG. 13. We can explain

quer this phenomenon as follows.

  In the case where many small jets 160, FIG. 16,

  hit a surface 163, there is a tendency to

  surface erosion 163. For a single jet, the degree of erosion

  sion is a function of the live force of the fluid, which is the

  produces mass of the fluid by its speed. So compared to

  wearing the single jet 166 having the same total live force as the total of the small jets 160, the erosion is less for

  small jets 160 because the mass associated with each pe-

  tit jet is less than that of the large jet and that each pe-

  tit jet has the ability to disperse its live force over a

  larger area of area 163 for the same dis-

  jet stream. The speed of the fluid leaving the hole is the same for the small jet as for the large jet

for the same pressure drop.

  Six embodiments of the present invention have been described.

  vention. However, one should not consider that the main

  cipes of the present invention are limited to these six modes

  for aviation applications. We consider

  dere that the present invention is applicable to any engine

  burning kerosene in which one wishes to increase the safety

fire protection.

  In addition, the holes or openings 45 are shown in FIG. 8 as being uniformly distributed. One of the

  goals of such a uniform distribution is to obtain ac-

  more uniform celerization over the entire cross-section

  versal of conduit 6. However, it is considered that a distribution

  Uniform holes are not strictly necessary.

  For example, it can be considered that the distribution of the holes 92, FIG. 9, is not uniform.

  In addition, the plate 75 has been described as covering certain selected holes 45 in order to prevent flow through them.

  This characteristic can be considered as changing the net opening through which

  fuel can flow out. It is obvious that we can-

  could use other arrangements than that which consists of

  close an opening. It is possible to modify the di-

  mensions or the shape of the openings.

  An important aspect of the present invention is the ac-

  rapid celerization of the anti-fogging fuel at a high speed to cause its degradation and this without using

  moving parts as would be necessary if

  read a pump directly to effect degradation.

  Furthermore, the applicant considers that the acceleration and the associated stresses which result therefrom in the fluid play a dominant role in causing the rupture of the polymers 24,

  Fig. 2, as opposed to the other possible solutions.

  Another important aspect of the present invention is that

  side in the covering and the covering of the holes 92 in FIG. 9. This results in the pressure drop and therefore the flow through each hole remaining approximately constant. You can change the total flow

  by changing the number of holes discovered. This is in con-

  traste with another possible solution, namely, that which would consist in using a fixed number of holes, and in making

  vary the flow by varying the load loss through

  towards these holes. In such a case, results can be obtained

  acceptable degradation states over a wide range of fuel flows but the range of variations in

  pressure required to provide the desired interval of

  bits of fuel becomes of impractical magnitude.

  The plaintiff's solution of using a multiplicity of openings rather than a single opening has the additional advantage of alleviating the problems

  described above. A solution with pressure variation

  The prior art uses a single opening and thus a single stream of fuel. For losses

  large load, the live forces of the currents

  bustible are very high which promotes strong erosion.

  In contrast, the solution of the present invention maintains the live force by relatively low current but varies

  the number of currents used to modify the to-

tal.

  In other words, the plaintiff carried out a

  the unit of degradation which resembles the opening 45 of FIG. 6 and, in order to modify the fuel flow rate, the applicant modifies the useful number of these cells, by

  example, by moving the piston 86 of FIG. 10.

Claims (10)

  1 - Method for distributing an anti-misting fuel to an engine by a conduit (6), characterized in that it consists in accelerating the anti-misting fuel while it is in the conduit in order to degrade the anti-fuel -fogging. 2 - An apparatus for degrading an anti-misting fuel which flows in a conduit (6), characterized in that it comprises: (a) a partition (15) which obstructs the flow of fuel; (b) a series of perforations (45) formed in the partition to accelerate the fuel as it flows in these perforations.   3 - Apparatus according to claim 2, characterized in that the partition (15) is positioned approximately normal to   the fuel flow direction.   4 - Apparatus according to claim 3, characterized in that   the perforations (45) have a circular cross section.   - Apparatus according to claim 4, characterized in that   the perforations (45) are delimited by walls approximately   matively cylindrical which are approximately perpendicular   circles on the surface (15A) of the partition and thus form   circular holes with sharp edges.   6 - Apparatus according to claim 5, characterized in that   the perforations (45) are uniformly distributed.   7 - Apparatus according to claim 6, characterized in that   that it further comprises means for adjusting the dimensions   useful perforations to control both the flow and acceleration of the fuel flowing at through them.   8 - Apparatus for degrading the reticulated structure of a   anti-fogging aviation fuel, characterized in that it comprises: acceleration means (15, 18; 15, 45; 88C, 92) for accelerating the fuel at high speed, the   acceleration means having no moving parts.   9 - Apparatus for degrading an anti-fogging fuel, characterized in that it comprises: (a) a cylinder (98C)   which contains at least one inlet and several ports   output ports (92); (b) a piston (86) for sealing a   selected number of outlet ports to control the   bit of fuel flowing through them; and (c)   pressure generating means (3) for applying pressure   fuel at the inlet port to accelerate fuel through the outlet ports so to degrade the fuel.   - Apparatus according to claim 9, characterized in that   that (a) the maximum diameter of the outlet holes is ap-   approximately 1.143 mm; and (b) the derivative of the change in the total cross-sectional area of the outlet holes from the change in the position of the piston is non-linear and increases when the cross-sectional area transverse increases.   11 - Apparatus for reducing the erosion of the elements of a   fuel pump and to degrade an anti fuel   engine mist, characterized in that it comprises: (a) acceleration means (92) for accelerating the fuel and producing a series of accelerated fuel streams; (b) a manifold (94) for receiving the series of   fuel streams and direct them to a conduit (95).   12 - Apparatus according to claim 11, characterized in that   that the means of acceleration include a series of openings   tures (92) which produce a pressure drop and through   which the fuel is accelerated.   13 - Apparatus according to claim 12, characterized in that   that it further comprises means for closing off or   vertices chosen to prevent fuel from escaping ler through these openings.