JPH03274318A - Burner - Google Patents

Abstract

PURPOSE:To lower a wall temperature, and to improve thermal efficiency, antioxidation, thermal impact resistance by superposing a second wall on a first wall made of a porous heat resistant material having a connection hole of a thickness direction in a burner for a rocket engine, etc., providing a fuel supply passage, and forming a wall. CONSTITUTION:The wall of a cylindrical burner is formed in a double structure wall in which a first wall 1 is superposed in contact with the entire inner surface of a second wall 2 made of Hastelloy X. The wall 1 is formed of porous SiC fiber reinforced SiC. Both ends of the walls 1, 2 are coupled by a coupling plate made of Hastelloy X and bolts. Many holes are formed in parallel on the outer surfaces in contact with the walls 1, 2 along longitudinal and circumferential directions to form a fuel supply passage 3, and connected to a fuel cylinder. With this structure, a wall temperature is lowered, and its thermal efficiency, antioxidation and thermal impact resistance can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a combustor that uses liquid as a main fuel and is used in gas turbine engines, rocket engines, and the like.

[Conventional technology]

In various gas turbine engines and rocket engines,
In the combustor, which is the main part of the combustor, liquid fuel is injected in gaseous form and mixed with air or an oxidizing agent such as oxygen to burn it. The part in contact with Hastelloy
It is made of heat-resistant alloy such as Loy X).

However, there are limits to the heat and humidity resistance of heat-resistant metal materials such as Hastelloy The metal materials that make up the combustor wall were protected by methods such as blowing out.

However, when the combustor wall is cooled, the wall humidity decreases,
Since the humidity of the gasified liquid fuel, air, etc. decreases, there is a problem in that the thermal efficiency of the combustor and engine decreases.

In recent years, SiN, which has excellent strength under high temperatures, and ceramics, which cost ¥810+, have been used as structural materials for engines.
The use of carbon, composite materials of these with fibers or whiskers, or materials coated with these on metal surfaces is being considered, but these heat-resistant materials tend to crack or break due to thermal stress caused by thermal cycles. There were drawbacks that could easily occur.

[Problem to be solved by the invention]

In view of such conventional circumstances, an object of the present invention is to provide a combustor that can increase thermal efficiency while keeping the temperature of the wall portion lower than before, and has excellent oxidation resistance and thermal shock resistance. do.

[Means to solve the problem]

In order to achieve the above object, in the combustor of the present invention,
At least a part of the wall has a double wall structure of a first wall and a second wall, the first wall is made of a porous heat-resistant material having at least communicating holes in the thickness direction, and the first wall It is characterized by having a fuel supply passage communicating with a communicating hole in the first wall at or between one or both of the first wall and the second wall.

The porous heat-resistant material that forms the first wall and the bottom of the tank may be heat-resistant alloys such as Hastelloy Or conventionally known heat-resistant materials such as composite materials with whiskers, which are perforated or porous by known methods to connect various forms such as oven bores, honeycomb shapes, three-dimensional network structures, or woven fabrics. It is porous and has pores. Therefore, specific examples of the first wall include, for example, a porous heat-resistant alloy having honeycomb-shaped continuous holes as shown in FIG. 1, an oven bore or a woven fabric as shown in FIGS. There are porous ceramics or ceramic composite materials having continuous pores.

In addition, as a material for the second wall, it does not break under the pressure of combustion,
Any material may be used as long as it is not porous and can be constructed into a wall structure that does not allow fluid such as liquid fuel to leak. For example, it may be a heat-resistant alloy conventionally used as a combustor or engine member.

In order to form a double wall structure of the first wall and the second wall using the above materials, it is preferable to mechanically connect the first wall and the second wall because the first wall is porous. For example, the ends of the first wall and the second wall can be connected with a connecting plate made of a heat-resistant alloy, and the ends can be connected using bolts, bottles, or the like.

In the combustor of the present invention, liquid fuel, or a liquid or gas-liquid mixed phase fluid containing liquid fuel is used as the fuel. The fuel fluid flows through the first wall 1 and the second wall 2 as shown in FIGS. 1 to 3.
The fuel is supplied under pressure to the combustion side, passes through the communication hole in the first wall 1, and is injected from the combustion side surface 4 on the opposite side to the second wall 2, and is mixed with an oxidizing agent such as air or oxygen that is supplied separately. Burn.

Note that the fuel fluid is supplied to the first wall 1 without containing an oxidizing agent such as air or oxygen so that combustion does not occur within the first wall 1.

The shape of the fuel supply path 3 that supplies the fuel fluid to the second wall 2 side of the first wall 1 may be determined depending on the form of the communicating holes in the first wall 1, etc. For example, if the first wall 1 is made of a porous heat-resistant alloy that has a honeycomb shape with communicating holes throughout the thickness, as shown in Figure 1, the entire space between the first wall 1 and the second wall 2 is Unless a gap is provided to form the fuel supply path 3, fuel cannot be uniformly injected from the entire combustion side surface 4 of the first wall 1.

However, if the first wall 1 is made of porous ceramics having three-dimensionally communicating pores such as an oven bore or a woven fabric, the first wall 1 and the second wall 1 are wall 2
In addition to forming a gap throughout the gap, as shown in Figure 2, the second wall 2
A plurality of horizontal holes are formed inside the second wall 2 in the longitudinal direction, and vertical holes or grooves are partially formed inside the second wall 2 from the horizontal holes to the porous first wall 1 side. It is also possible to configure the supply passage 3, or to directly provide a plurality of through-hole-shaped fuel supply passages 3 in the porous first wall 1 in the longitudinal direction as shown in FIG.

[Function] In the combustor of the present invention, the fuel fluid passes through the communication holes in the first wall 1 in a liquid state and flows from the second wall 2 side toward the combustion side surface 4 on the opposite side. As the combustion side surface 4 is heated by radiation, a heat flux toward the inside of the first wall 1 is generated, so that heat transfer from the first wall 1 to the fuel fluid occurs while the fuel fluid flows through the communicating holes. occurs and the fuel fluid vaporizes.

When this fuel fluid undergoes a phase transformation from a liquid phase to a gas phase, the first wall 1
Compared to conventional gas-only or liquid-only cooling means, the combustor of the present invention itself has a large cooling capacity because it removes a large amount of heat inside the combustor.

Furthermore, since the direction of heat transfer within the second wall 1 and the direction of movement of the fuel fluid that takes away that heat are opposite, the heat flow rate toward the second wall 2 becomes extremely small, and the fuel fluid is heated. and is ejected to the combustion side. As a result, the heat loss from the combustion gas to the combustor is reduced, the sintering temperature is increased, and the thermal efficiency is significantly increased.

Further, the fuel fluid passing through the second wall 1 is vaporized while flowing through the second wall 1, and is ejected from the combustion side surface 4 of the second wall 1, and is mixed with an oxidizer separately supplied to the combustion side. Since they are mixed and combusted, the oxygen partial pressure in the boundary layer of the sintered surface 4 becomes low, making it difficult for the third wall 1 to be oxidized. Also, the combustor
Since the wall 1 itself is porous, the apparent thermal conductivity of the first wall 1 is low, and its thermal shock resistance under thermal cycles is superior to that of ordinary dense materials.

The average pore diameter of the continuous pores in the porous heat-resistant material of the second wall is preferably in the range of 0.1 to 20 mm. This is because if the average pore diameter of the communicating pores is less than 0.1stllK, the viscous resistance of the fuel fluid flowing through the pores becomes large, and if it exceeds 201111, it becomes difficult to obtain a uniform flow of the fuel fluid within the pores.

In addition, the porous heat-resistant material of the second wall has a porosity of 10 to 95%.
degree is preferred. The reason for this is that if it is less than 10%, cooling by the fuel fluid will be insufficient, and if it exceeds 95%, the mechanical strength of the first wall will be insufficient.

Furthermore, the thickness of the second wall is preferably about 2 to 100 fi. The reason for this is that if it is less than 2fi, the cooling by the fuel fluid will be insufficient, and if it exceeds 100gIs, there will be little change in the cooling characteristics and only an increase in weight will occur.

(Example) The inner wall (
A porous SiO fiber-reinforced Si material having a cylindrical shape with an average thickness of 10 tll and an inner diameter of 50 m was used as the 1st wall), and both ends of the 1st wall and the 2nd wall were connected by connecting plates and bolts made of Hastelloy X. mechanically bonded using In addition, on the outer surface of the first wall in contact with the second wall, there are a number of holes arranged in parallel at intervals of 10 degrees along the length direction and the circumferential direction, with a diameter of 2 m and a depth of 1.
0fi perforations were provided, and these many perforations were used as fuel supply channels, and the inlets thereof were connected to liquid fuel cylinders. Further, the porous SiC fiber-reinforced SiO constituting the second wall had an average pore diameter of 0.7 and a porosity of 54%. In addition, the production of this porous SiO fiber reinforced SiO is as follows:
CVI (
Chemical Vapor Infi7tratio
n) to form stc v trix. Raw materials for CVI include OH, 5i(J.

The reaction was carried out using H under the reaction conditions of 1400 C" and 5 to 10 torr.

From one end of the cylindrical combustor to porous SiC fiber-reinforced Si
While supplying oxygen into the combustion chamber surrounded by the cylindrical first wall of O, liquid hydrogen is injected under pressure from the liquid fuel cylinder into the fuel supply path, and inside the cylindrical first wall of porous SiO fiber reinforced SiC. The combustion gas was ejected from its surface into the combustion chamber through the tube, and the combustion gas was discharged from the other end. Note that the first and second walls of the cylindrical combustor were not cooled. During steady combustion, the outer wall humidity of the second wall made of Hastelloy X was 108 C'', and the combustion gas temperature was 1310 C''. Also, after the completion of combustion,
When the walls were inspected, no damage or decrease in thickness was observed.

As a comparative example, a cylindrical combustor similar to the above was used, but
An inner wall (second wall) made of a porous heat-resistant material was not provided, and only a cylindrical wall (second wall) made of Hastelloy X was provided. However, so that the combustion chamber had an inner diameter of 50 mm, which is the same as in the above example, a cylindrical wall made of Hastelloy The outside of this cylindrical wall was water-cooled by a water jacket, and oxygen and liquid hydrogen were injected from one end of the cylindrical combustor into the combustion chamber inside the cylindrical wall, and combustion was performed at the same fuel consumption rate as in the above example. The outer wall humidity of the cylinder wall during steady combustion was 92C1, and the combustion gas humidity was 1060C''.

In addition, when the cylinder wall was observed after combustion, it was found that the inner Si
Peeling was observed in the C coating film.

〔Effect of the invention〕

According to the present invention, the humidity in the wall can be suppressed lower than before, so there is no need for ordinary cooling means or a smaller cooling capacity than before, and it has high thermal efficiency and has good oxidation resistance and thermal shock resistance. It is possible to realize an excellent combustor.

The combustor of the present invention is particularly effective as a combustor or afterburner for gas turbine engines or ramjet engines that use jet fuel, or as a combustor for rocket engines or scramjet engines that use liquid rocket fuel such as liquid hydrogen or hydrazine. It is.

[Brief explanation of drawings]

FIGS. 1, 2, and 3 are schematic sectional views showing specific examples of the combustor according to the present invention. 1. Second wall 2. Second wall 3. Fuel supply path 4. Combustion side surface continuation correction amount (spontaneous)

Claims (2)

[Claims] (1) At least a part of the wall has a double wall structure of a first wall and a second wall, and the first wall is made of a porous heat-resistant material having at least communicating holes in the thickness direction, A combustor comprising a fuel supply passage communicating with a communicating hole in the first wall at or between one or both of the first wall and the second wall. (2) The combustor according to claim (1), wherein the average pore diameter of the communicating holes in the porous heat-resistant material constituting the first wall is 0.1 to 20 mm.