Abstract:
A system for cooling a structure or mechanism through transpiration processes. Generally a porous structural material may be used to form a hot wall surface of a high temperature or high heat flux environment component, typically used in combustion type devices. Coolant pressurized on the “cold” or cooler side of the wall is bled, “sweated”, or otherwise transpired to the “hot” wall surface in an effort to control the hot wall surface temperature by shielding the surface with a coolant layer at the surface and by removing heat via coolant flow past the surface. This may be done to manage the hot wall temperature for structural purposes, more effectively manage high heat fluxes, or to hide thermal signatures. The porous material can be selectively made such that the coolant material flows substantially in one direction only through the porous material to transfer thermal energy only away from the structure rather than towards the structure.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates generally to cooling systems for transpiration cooling, and particularly to systems and methods of forming selectively porous laminate materials for transpiration cooling.  
       BACKGROUND OF THE INVENTION  
       [0002]     Many materials are known to be porous, generally being inherently porous. The naturally porous materials can be provided as filters or as transpiration coolers for various applications. Nevertheless, many natural materials include a porosity that is also substantially “natural”. Simply, the natural porosity of many materials is highly variable. Although porosity for various materials may be within a generally known range, the porosity can be unevenly distributed throughout the material. Moreover, the natural porosity of a selected material may be within a large range rather than within a narrow porosity range. Furthermore, a material having a selected porosity may not include other selected or desirable characteristics, such as strength.  
         [0003]     Nevertheless, it is desirable to provide materials that include a selected porosity, and more specifically a porosity that is substantially consistent throughout the material such that natural variations do not occur within the material. Therefore, the porosity will include a selected porosity and pore size. The entire material should have a known physical characteristic and capable of being applied in a substantially consistent manner.  
         [0004]     Moreover, most often porous materials include a substantially multi-directional porosity. That is, the porosity is distributed such that flowable materials may move through the pores in both directions, from a first side to a second side and from the second side to the first side of the material. If the porous material is provided as a filter or membrane, a pressure differential across the membrane must be relied upon to move the material in a selected direction. Generally, this requires including additional manufacturing steps or structural elements in the final structure or device.  
         [0005]     Therefore, it is also desirable to provide a material that is substantially directionally porous. Simply, a material that includes a porosity that allows material to flow in only one direction relative to the porous material. With a pressure differential supplied across the membrane, the pores of the membrane would allow a flow of material in only one direction. The flow may be dependent upon the material in which the pores are made or the material being flowed across the membrane; nevertheless, the membrane may be substantially uni-directional in its porosity for selected flowable materials.  
         [0006]     It is also desired to provide many materials including selected porosities. That is, materials of various types including a selected porosity that include both a selected pore density, selected pore size, and selected directional porosity. Therefore, rather than providing only a single material including a selected porosity with a general technique, the materials could be varied and used in many different applications including different strengths and weight requirements that may be provided by various materials.  
         [0007]     Also, it is known to cool various components, such as components of a rocket engine including turbine parts, combustion chambers, and nozzles. Cooling these systems in particularly harsh environments can be difficult due to the high heat flux, strength, and heat resistance needed of the various cooling components. Therefore, providing a cooling system in such an environment is often difficult, heavy, complex, or expensive. In addition, the cooling systems are generally large and bulky due to the requirements for heat transfer and strength in the environment. Therefore, it is also desirable to provide a cooling system that can easily cool a component in a harsh environment without great size or complexity.  
       SUMMARY OF THE INVENTION  
       [0008]     The invention provides a system for providing pores in a structure according to selected properties. Generally a structure, such as a laminate, may be formed with a selected pore according to a selected porosity or other physical attributes. The porosity may be formed by positioning pins or pore forming members through a laminate preform before the preform is processed to form the laminate structure. After forming the laminate structure the pins can be removed according to various processes which do not harm the physical characteristics of the laminate structure. Therefore, the porosity of the final laminate material is provided according to a selected size, direction, distribution, and porosity rather than being generally random according to a natural process.  
         [0009]     The invention further provides a system for cooling a component through substantially transpiration processes. A laminate material including required physical characteristics, such as strength or toughness, and including selected pores, is provided adjacent or around the apparatus to be cooled. The selected pores allow for transpiration of a coolant which can be flowed between the porous material and the apparatus to be cooled or the source of the heat flux. The coolant, which is transpirated through the porous member or structure, absorbs thermal energy from the apparatus to be cooled or heat source. This removes thermal energy from the apparatus and allows a selected temperature of the apparatus to be maintained during operation of the apparatus. Therefore, only the coolant material and an area for the coolant material to flow is required between the apparatus and the porous membrane. Thus, a small system is provided for cooling the selected apparatus.  
         [0010]     The invention further provides, according to an embodiment a way to cool a structure by transpirating a material through the structure wall. For example, a structural component that is subject to high heat fluxes may include or be formed of a porous material. A coolant may then be provided to flow through the porous material from a coolant source and be evaporated on the hot side of the porous material to cool the porous material, thereby keeping the porous material, which is the structural component, at a selected temperature. This transpiration or “sweat” cooling allows the coolant material to be flowed through the structural component being cooled without requiring additional or bulky components that must be provided to pump or transport a coolant adjacent a structural component to be cooled. Rather, the coolant flows through the structural member to cool it on contact. Also, various cooling conduits, evaporators, and compressors would not be necessary.  
         [0011]     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and various examples are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0013]      FIG. 1  is a cross-sectional view of a laminate including pores according to an embodiment;  
         [0014]      FIG. 2  is an exploded view of the laminate and a pore forming apparatus;  
         [0015]      FIG. 3  is an assembled view of a laminate and a pore forming apparatus;  
         [0016]      FIG. 4A-4C  is a pore forming apparatus according to various embodiments;  
         [0017]      FIG. 5  is a diagram of a transpiration cooling system according to an embodiment of the invention;  
         [0018]      FIG. 6  is a detailed cross-sectional view of a leading edge of an airfoil according to an embodiment of the invention; and  
         [0019]      FIG. 7  is a cross-sectional detailed view of a nozzle including an embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0020]     The following description of various embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0021]     With reference to  FIG. 1 , a laminated structure  10  includes at least two layers, a first layer  12  and a second layer  14  formed generally adjacent one another. In addition, an intermediate layer  16  may be formed or positioned between the first and second layers  12 ,  14 . The intermediate layer  16  may be used for adhering the first and second layers  12 ,  14  to one another during a formation or laminating process. Nevertheless, it will be understood that laminated layers may include a pre-impregnated material which can be used to affix the first and second layers  12 ,  14  together during the formation process. Alternatively, the first and second layers  12 ,  14  may be fixed to one another, during the formation process, without any additional adhesive material. Also, it will be understood that the laminate structure  10  may include any number of appropriate layers. Simply, only illustrating the first layer  12  affixed to the second layer  14  is for clarity and is merely exemplary and not intended to limit the scope of the present disclosure. Therefore, the laminate structure  10  including any appropriate number greater than the two structural layers  12 ,  14  and a single intermediate layer  16  may be used.  
         [0022]     Formed through the laminate  10  are a plurality of bores or pores  20 . The pores  20  can be formed through the laminate  10  in any appropriate or selected manner. Generally, however the pores  20  are formed such that a uniform density or porosity is formed in a selected area such as a first set of pores  22 . Moreover, the pores may be formed such that a non-porous area  24  is also formed. Furthermore, the pores  20  may be formed to include desired physical characteristics such as being uni-directional. For example, a plurality of uni-directional pores  26  allow the flow of a flowable material from a first side  12   a  to a second side  14   a . It will be understood that the uni-directional pores  26  may also be formed such that material flows substantially only from the second side  14   a  to the first side  12   a . In addition, due to the formation of the uni-directional pores  26 , it may be that the uni-directional pores  26  are positioned in any selected area of the laminate  10  D. The pores  20  may also include an angled pore or pores  28 . The angled pores  28  may be formed an any selected angle θ relative to a side  12   a  or  14   a  of the laminated structure  10 . This allows for a cooling or a flow of material from one selected position to another selected position through the laminate structure  10 .  
         [0023]     The first laminate layer  12  and the second laminate layer  14  may generally be formed of any appropriate material, for example non-oxide or oxide ceramic matrix composite materials. Alternatively, both the first layer  12  and the second layer  14  may be formed of a silicon carbide material reinforced with carbon fibers and formed in an appropriate manner. As a further example, oxide layers may include alumina or alumina silicates with or without reinforcement fibers such as alumina, sapphire, or quartz. Therefore, it will be understood any appropriate material may be used.  
         [0024]     Generally, the first and second layers  12 ,  14  are formed to include selected physical characteristics, such as strength or durability. In addition, the first and second layers  12 ,  14  may be formed of a material that includes other physical characteristics such as thermal or electrical conductivity. It will be understood that the layers  12 ,  14  may be substantially non-porous. Moreover, after the laminate  10  is formed, it may include generally no pores except for the manufactured pores  20 . The materials may also be reinforced with various fibers or materials, such as carbon or metal fibers. When the first and second layers  12 ,  14  are laminated together in the laminate structure  10 , the laminate structure  10  includes the selected physical characteristics. The pores  20  formed in the laminate structure  10  are formed without destroying the selected physical characteristics of the laminate structure  10 . Physical characteristics may also include inherent strength or toughness of the laminate structure  10  in addition to characteristics of the various layers. Thus the laminate structure  10  may include both selected physical properties and porosity.  
         [0025]     Forming the pores  20  through the laminate  10  as the laminate  10  is formed substantially ensures that the porosity or the pores  20  formed in laminate  10  are formed in a selected manner and according to selected requirements. Selectively forming the pores  20  also helps ensure a selected and complete porosity. Also, forming the pores  20  during the manufacturing of the laminate  10  ensures that the formation of the pores  20  or the presence of the pores  20  does not substantially destroy the selected physical or chemical characteristics of the laminate  10 . It will be understood a limited amount of degradation may occur but not so much as to significantly affect selected properties of the material overall or the laminate  10 .  
         [0026]     With reference to  FIG. 2 , the pores  20  (illustrated in  FIG. 1 ) may be formed using a pore forming apparatus  30 . The pore forming apparatus  30  generally includes a base  32  and a plurality of pins or pore forming members  34  extending from the base  32 . Generally, the pins  34  include a relatively sharpened top or engaging end  36  that is used to pierce a portion of a laminate preform  40 . The laminate preform  40  includes each of the layers which will form the laminate structure  10 , but which have not been laminated that is the process to make each of the layers  12 ,  14  substantially coherent has not occurred. The pins  34  pierce the laminate preform  40  to form desired pores in the laminate preform  40  which become the pores  20  once the pins  34  are removed. As the pins  34  pierce the laminate preform  40 , they can push aside any reinforcement fibers without substantially breaking or weakening the fibers. The pins  34  allow for the formation of the pores  20  in the laminate structure  10  without substantially weakening any structural properties of the laminate structure  10 . In part, this is done by not destroying any reinforcement fibers that are positioned in the laminate perform  40 .  
         [0027]     With continued reference to  FIG. 2  and additional reference to  FIG. 3 , the laminate preform  40  is pressed onto the pins  34  a selected distance. Generally, the pins  34  include a height to provide a pore depth of a selected depth through the laminate structure  10 . Generally, providing pores through laminate structure  10  is selected such that a flowable material is able to pass from the first side  12   a  to the second side  14   a . The pore forming apparatus  30  can be pressed through the laminate preform  40  or the laminate preform  40  pressed onto the pore forming apparatus  30 . Nevertheless, the pins  34  generally engage and pass through selected layers of the laminate preform  40  to form regions that become the pores  20  in the laminate structure  10 .  
         [0028]     The pins  34  may be formed or placed on the base  32  of the pore forming apparatus  30  in any appropriate shape or pattern. Moreover, the pin forming apparatus  30  may be shaped to any appropriate geometry. In this way as the laminate preform  40  is placed over the pore forming apparatus  30  it conforms to the shape of the pore forming apparatus  30  such that a complimentary shape or a similar shape is formed in the laminate preform  40  as the pores  20  are formed in the laminate preform  40 .  
         [0029]     Because the pins  34  may be positioned on the base  32  in any appropriate design or pattern, selected porosities or designs of porosities can be formed in the laminate  10 . In addition, each of the pins  34  positioned on the base  32  may be of a selected size or geometry. Therefore, a first set of the pins  34  may be a first size, while a second set is a different size. Moreover, the pins  34  may include a selected geometry to create a uni-directional pore, such that the flowable material passes only in one direction, and again only some of the pins placed on the base  32  may include this attribute while others do not.  
         [0030]     With reference to  FIG. 4A  to  4 C, exemplary pore forming geometries are illustrated. With particular reference to  FIG. 4A , the pore forming apparatus  30   a  includes a plurality of the pins  34  formed into a plurality of rows  42   1  to  42   n . An opening  44  is left in the pattern such that pores will not be formed in a selected area of the laminate  10 . The open area  44  may be any appropriate shape or size and may used for forming an opening or hole in the laminate  10 . Particularly, if there is an opening for a rod or tube, no pores would be formed therein.  
         [0031]     With particular reference to  FIG. 4B , the pore forming apparatus  30   b  includes a first set of pins  46  having a first diameter X and a second set of pins  48  having a second diameter Y. The first diameter X may be any diameter different, yet appropriate, than the diameter Y. Therefore, the laminate  10  will have pores formed therein that include pores of various sizes. This may be desirable especially if the laminate  10  is to be used cover to adjacent sections requiring a different size pore in each section. This technique may also be used to vary the transportation of material across the laminate  10 .  
         [0032]     With particular reference to  FIG. 4C , a pore forming apparatus  30   c  includes a first section of pins  50  and a second section of pins  52 . The first section pins  50  may be formed in a particular pattern, such as a triangle for forming pores in the laminate  10  in the selected pattern. Moreover, the pins in the first section  50  include a first density which is different than the density of the pins in the second section  52 . Furthermore, the shape or general pattern of the second set of pins  52  may differ from to the first set of pins  50 . Further, the pins  52  may be set at any angle for the intended creation of pores which traverse the laminate at the angle relative to the laminate surface  12   a  or  14   a  (See  FIG. 1 ). Therefore, several different pore forming apparatus can be produced to provide various different porosities, pore sizes, pore shapes or pore patterns. In this way the laminate  10  may include a porosity of any selected manner.  
         [0033]     The laminate structure  10  can be formed according to any appropriate method. Depending upon the material from which the laminate structure  10  is formed, the method for selectively forming the pores  20  in the laminate structure  10  may vary. Moreover, the layers  12 ,  14  of the laminated structure  10 , which are first placed adjacent one another in the preform  40 , may be substantially non-porous. Thus, substantially all pores formed in the laminated structure  10  would be through the removal of the pore forming members  32  from the laminated structure  10  after the laminate preform  40  had been laminated.  
         [0034]     Various methods include, forming selected pores in a non-oxide material may require specific etching or non-oxide melting methods. For example, forming selected pores in the laminate structure  10  when the laminate structure  10  is formed of a non-oxide material is disclosed in U.S. patent application Ser. No. ______ (Attorney Reference No. 7784-000564) entitled “Method and Apparatus For Processing Non-Oxide Selectively Porous Materials”, to Miklos Paul Petervary and Min Zhou Berbon, and commonly assigned. It will be understood, however, that any appropriate method may be used for forming the laminate structure  10  that includes the selected pores  20  for use according to various embodiments of the invention.  
         [0035]     With reference to  FIG. 5 , a transpiration cooling system  56 , for use in various applications, is illustrated. The transpiration cooling system  56  is intended for use with an apparatus or component  60  which is required to be cooled, although it will be appreciated that the apparatus  60  does not form a part of the system  56 . The apparatus  60  may include any appropriate item such as a turbo pump or turbine for various applications, such as a rocket engine or turbine engine. It will also be understood that the apparatus  60  may include items such as the exterior of a turbine engine, for example an engine for an aircraft, and other appropriate apparatus which may produce or transport heat containing or producing items.  
         [0036]     For example, the apparatus  60  may transport a heated fluid  62 . As the heated fluid  62  is transported through the apparatus  60 , a wall or exterior  64  of the apparatus may become heated due to a heat transfer or thermal energy transfer from the heated material  62  to the wall  64  The apparatus  60 , however, is generally maintained at a selected temperature.  
         [0037]     Positioned around the wall  64  of the apparatus  60  may be the laminate structure  10 . The laminate structure  10  includes the plurality of pores  20  formed therein. The pores  20  are formed in the laminate structure  10  to have a selected physical property relative to the laminate structure  10  or another material. For example, a cooling or radiating material  70  may be provided in an area or cooling space  72  between the laminated structure  10  and the wall  64  of the structure  60 . The cooling material  70  is provided from a cooling supply  73 . The cooling material  70  may flow in the cooling area  72  and through the pores  20 . Generally, the cooling material  70  would move from the first side  12   a , or inside in this instance, to the second side  14   a , or outside, of the laminate structure  10 .  
         [0038]     As the cooling material  70  moves from the first side  12   a  to the second side  14   a , thermal energy is also moved from the cooling area  72  to the second side  14   a  of the laminate structure  10 . As the cooling material  70  moves within the cooling space  72 , it absorbs thermal energy from the wall  64  of the structure  60 . Therefore, as the cooling material  70  moves away from the wall  64  thermal energy is also moved away from the wall  64 . This cools the wall  64  and cools the apparatus  60 . Generally, the passing of the cooling material  70  through the pores  20  of the laminate structure  10  is by the process of transpiration. More specifically, the cooling of or removal of thermal energy from the apparatus  60  is by transpiration cooling of the apparatus  60 . Therefore, providing the laminate structure  10  with pores  20  and flowing the coolant material  70  such that it absorbs thermal energy and moves the thermal energy away from the apparatus  60  allows transpiration cooling. This allows the apparatus  60  to be maintained at a selected temperature.  
         [0039]     Because the material  70  moves away from the structure  60 , the structure  60  is able to maintain the transference of the material  62  through the structure  60 . This allows the structure  60  to be formed of a material which is substantially less heat resistant than if the apparatus  60  were not cooled by the cooling material  70 . Moreover, the structure  60  may be cooled by only providing the laminate structure  10  and the supply  73  of the cooling material  70 .  
         [0040]     The cooling material  70  flows through the cooling area  72  and through the pores  20  according to natural or inherent mechanisms. For example, the pores  20  may be formed in the laminate structure  10  to have a substantially uni-directional property. The pores  20 , particularly the uni-directional pores  26 , allow the coolant material  70  to move in only one direction relative to the laminate structure  10 . That is, the uni-directional pores  26  allow the cooling material  70  to move from the cooling space  72  to the exterior  14   a  of the laminate structure  10  and not from the exterior of the laminate structure  14   a  to the cooling space  72 . Thus, the transfer of thermal energy occurs in substantially only one direction. In addition, the pressure created within the cooling area  72 , due to the heating of the cooling material  70 , also assists in driving the cooling material  70  through the pores  20  of the laminate structure  10 .  
         [0041]     Due to the selected formation of the pores  20  within the laminate structure  10 , selected amounts of cooling may occur around the structure  60 . This allows for varying cooling rather than providing a substantially uniform cooling. Because the pores  20  are selectively formed in the laminate structure  10 , the porosity, size, and direction of the pores  20  can be selected. Therefore, the single laminate structure  10  can include a plurality of regions to allow for varying degrees of cooling and transpiration. For example, a specific area of the apparatus  60  may need to be cooled more rapidly than another area of the apparatus  60 . Therefore, a greater porosity or size of pores can be provided in that area of the laminate structure  10  relative to the apparatus  60 . However, if less cooling is required in a different area a lesser porosity may be provided in favor of greater material density of the laminate structure  10  to allow for greater rigidity.  
         [0042]     Uni-directional pores may also be used to transfer thermal energy from one area to another of the apparatus  60 . In a first area, the laminate structure  10  may provide for a removal of heat from the apparatus  60  by moving the coolant material  70  from the cooling area  72  to the exterior  14   a  of the laminate structure  10  and further uni-directional pores allow for the coolant material  70  to move from the exterior  14   a  to the coolant area  72 . Therefore, thermal energy may be transferred from one area to another thereby allowing cooling of one region and heating of another region of the apparatus  60 . Nevertheless, the plurality of pores  20  in a laminate structure  10  can be formed for any selected properties or structure.  
         [0043]     In addition, because the pores  20  are formed within the laminate structure  10  during a processing step, the laminate structure  10  can include any selected physical property. For example, the laminate structure  10  may include a selected tensile strength such that the laminate structure  10  may be included as a structural component of the apparatus  60 . Therefore, rather than simply providing a cooling mechanism for cooling the structure  60 , the laminate structure  10  may also be provided as a structural component of the apparatus  60 .  
         [0044]     Moreover, because the laminate structure  10  can be selected of various materials, the materials which form the laminate structure  10  can be selected to withstand any environment in which the apparatus  60  is placed. Therefore, if the cooling system  56  is positioned within a rocket engine, which may reach high temperatures, the material of the laminate structure  10  can be selected to withstand such high temperatures. For example, the laminate structure  10  can be formed of an oxide, substantially a ceramic, which includes various laminated oxide layers that may withstand extremely high temperatures. Also, because the laminate structure  10  is formed of a plurality of layers  12 ,  14  that are laminated together, the laminated structure  10  includes inherent strengths. Moreover, the various layers can be chosen to provide even greater strengths or other physical properties. These strengths are maintained or enhanced in part because the pore-forming members  34  are positioned in the laminate preform  40  before the laminate structure  10  is formed. Therefore, the final laminate structure  10  includes selected properties that are uninhibited by the inclusion of the plurality of pores  20 .  
         [0045]     It will be understood that the laminate structure  10  can be used in the cooling system  56  for cooling the selected apparatus  60 . It will be understood that the structure  60  may be any appropriate structure which is required to be cooled and can be cooled with transpiration cooling. Furthermore, it will be understood that the cooling material  70  may be any appropriate cooling material which can be provided in the cooling area  72 . It will also be understood that the laminate structure  10  can be provided in any appropriate shape to create the cooling area  72  around the apparatus  60 . For example, the apparatus  60  may be substantially cylindrical, therefore the laminate material may be provided in a substantially cylindrical shape to surround the apparatus  60 . Furthermore, the apparatus  60  may include irregularities in the wall  64  which can also be mirrored in the shape of the laminate structure  10 .  
         [0046]     With reference to  FIG. 6 , an apparatus to be cooled may include a turbine fan or fin, or particularly a leading edge apparatus  80  of any appropriate system such as a turbine blade or a leading edge of a plane wing for a vehicle which may be heated due to frictional air forces. Therefore, the edge fin  80 , is exemplary of any of these systems which include the leading edge  80  that may become heated due to frictional forces. Generally, an internal or structural component  82  provides an internal support for the edge  80 . An external surface or skin  84  of the fin edge  80  is formed of a porous material. A plurality of the pores  20  are selectively positioned along the fin edge  80 . The pores  20  are formed in the skin  84  of the fin edge  80  using the above-described methods. During the formation process, the skin  84  may be formed into any appropriate shape, such as the leading edge of the fin edge  80 . Moreover, the skin  84  may be formed as a leading edge of a wing for an aircraft and may include the appropriate aerodynamic properties. Nevertheless, the skin  84  may be formed of the ceramic materials, including oxides and non-oxides, that include appropriate or selected strength, environmental compatibility, and heat resistant properties.  
         [0047]     During use, especially when the skin  84  is heated due to frictional or other forces, the skin  84  may be cooled through transpiration. If the blade  80  is a blade of a turbine fan as it spins aerodynamic frictional forces increase the temperature of the leading edge  80  or the surface  84   a  of the skin  84 . If the blade  80  is exemplary leading edge of a wing of an aircraft, it will increase in temperature during flight, such as re-entry of a spacecraft. Nevertheless, the skin  84  is spaced a distance from the internal structure  82  thus forming a coolant pathway  86 . In the coolant pathway  86  is flowed a coolant  88 . The coolant  88  flows through the pores  20  in the direction of arrow B. That is, the coolant  88  flows from the coolant pathway  86  to an exterior  84   a  of the skin  84 . As the coolant  88  reaches the exterior of skin  84   a , heat is removed from the skin  84  through various means.  
         [0048]     The coolant  88 , as it flows through the pores  20 , can remove thermal energy from the skin  84  according to various methods. For example, as the coolant  88  flows through the exterior of  84   a , of the skin  84 , the coolant  88  may change phase, such as vaporizing thus turning from a liquid to a gas. This phase change cools the skin  84  and using some of the thermal energy on the exterior  84   a  of the skin  84  thereby cooling the skin  84 . In addition, sheer forces of the hot gases flowing around the exterior  84   a  of the skin  84  removes a volume of the coolant  88  as it flows through the pores  20 . Moreover, the coolant  88  is substantially constantly flowing through the pores  20  producing a film or coating on the exterior  84   a  of the skin  84 . The film of the coolant  88  also helps ensure that the skin  84  maintains a selected temperature  
         [0049]     Therefore, the skin  84  including the pores  20 , formed as described allows for transpiration cooling of the blade  80 . The coolant  88  removes thermal energy from the skin  84  according to any appropriate or physically possible method. Nevertheless, this transpiration of the coolant  88  through the pores  20  allows the coolant  88  to cool the skin  84 . Thus, the skin  84  can be kept at a selected temperature that does not compromise various properties of the skin  84 , such as strength or toughness. Moreover, the pores  20  formed in the skin  84  provide a substantially efficient method of cooling the skin  84  without providing substantially complex circuitry and cooling systems.  
         [0050]     With reference to  FIG. 7 , an apparatus  100  includes the pores  20  formed in a wall  102  as a structural component of a apparatus or device  100  subject to high heat fluxes. Generally, the heat fluxes may be formed by the flowing of hot gases or a flame, such as in a combustion chamber or in a nozzle of a rocket engine or the like. For example, hot gases may flow in the direction of arrow C within the wall  102  that includes a plurality of the pores  20  formed therein. Formed on an exterior of the walls  102  is an external or cooling plenum wall  104 . Space between the plenum wall  104  and the wall  102  of the apparatus is a cooling space or conduit  106 .  
         [0051]     Through the cooling conduit  106  flows a coolant  108  that is able to flow through the pores  20  into the heated area or a flow chamber  110 . The gases flowing in the direction of arrow C flow through the flow chamber  110  and substantially heat the walls  102 . Nevertheless, the coolant  108  flows through the pores  20  in the direction of arrow D to substantially cool the wall  102  to a selected temperature. As the coolant  108  flows through the pores  20 , it can change phases or cause a film to form on the interior of the wall  102 . As discussed above, a change in phase of the coolant  108  removes thermal energy from the wall  102  and allows it to be maintained at the selected temperature. In addition, the sheer forces on the film, which forms on the interior of the wall  102 , helps cool the wall  102  as the hot gases flow past the direction of arrow C. Any cooling method using the coolant  108  may be used to cool the wall  102 . Nevertheless, the wall  102  can be cooled by flowing the coolant  108  through the pores  20 . The only structure that is provided is the cooling plenum wall  104  to hold the coolant  108  relative to the hot wall  102 .  
         [0052]     Although the porous material has been illustrated to be a high heat flux hot wall of the turbine fan  80  or a rocket thruster nozzle  102 , it will be understood that the porous material may be used in any appropriate application. The porous material allows the coolant to flow from a supply area or conduit through the porous material to the hot wall side of the porous material. There the coolant may change phase or form a cooling film relative to the hot wall. This allows the hot wall to be maintained at a selected temperature while it surrounds an area of substantially high heat flux. For example, using the oxide and non-oxide ceramics, as discussed above, the porous materials may be used to cool areas and manage applications or designs having a heat flux beyond the capability of an actively cooled metal solution. Therefore, the porous ceramic matrix laminates can be used to contain substantially higher temperature higher heat flux reactions than presently available.  
         [0053]     Moreover, forming the porous laminated structures with the pin method, as described above, allows of the laminate structures to substantially maintain the physical properties of the laminate structure. Therefore, the selected porous properties can be formed in the laminate materials without sacrificing the physical characteristics of the laminate material, such as strength or toughness.  
         [0054]     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.