Solar Turbines Inc.

Virendra M Sood

Leslie John Faulder

Douglas C Rawlins

Mario Eugene Abreu

Robie L Faulkner

Kenneth H Maden

Dennis D Idleman

James B Sperling

The present method of making a workpiece having a plurality of holes defined therein includes the plurality of holes defining a specific flow at a specific flow condition. The method of making the plurality of holes includes generally the steps of forming a first portion of holes having a first preestablished hole cross-sectional area being defined by a predetermined flow characteristic value of the first preestablished hole cross-sectional area at the specific flow condition; a cavity being formed; positioning a flow establishing device in communication with the cavity; positioning a flow measuring device in operative relationship with the flow establishing device; actuating the flow establishing device and establishing a flow through the first portion of holes; monitoring the flow; comparing the flow with the predetermined flow characteristic value; determining a flow requirement of a second portion of holes based on an accumulative predetermined flow characteristic value of the first and second portions of holes and the measured flow of the first portion of holes; conforming the forming device to a second predetermined hole cross-sectional area and forming the second portion of said plurality of holes having the second predetermined hole cross-sectional area; and repeating the aforementioned steps successively for the remaining portions of the plurality of holes until the required number of holes in the workpiece have been formed.

Method and apparatus for making holes in a workpiece

An apparatus and method for determining and maintaining the temperature of a primary zone of a combustor of a gas turbine engine at a predetermined level is provided. A first sensor senses the inlet air temperature of the combustor, a second sensor senses the inlet temperature of the turbine gases, and a third sensor senses the speed of or measures the load of the engine. Based on the first and second sensed temperatures, the speed or the load, and the preestablished combustor design parameter, the primary zone temperature of the combustor T.sub.pz is calculated. A controller maintains the combustor at a predetermined setpoint temperature by moving an air bleed valve between open and closed position, or a plurality of inlet guide vanes between open and closed positions.

Apparatus and method for determining and controlling combustor primary

Past fuel injection nozzles have attempted to provide a structure to reduce tip temperatures. Such nozzles have failed to attain adequate reduction of tip temperatures without increasing the quantity of cooling air required. The present fuel injector structure has resulted in reduced tip temperatures without increasing the quantity of cooling air required. The structure includes a shell having an inner member positioned therein forming a first chamber therebetween, an end piece forming a second chamber between the inner member and the end piece. An inner body has a plurality of first angled passages formed therein and communicates between the second chamber and a passage. A flow of combustor air through the second chamber contacts an air side of the end piece resulting in a combustor side being cooled. The unique structure of the fuel injector nozzle provides improved tip cooling without increasing the quality of cooling air and improves the efficiency of the gas turbine engine.

Injector having low tip temperature

Past systems have attempted to cool the combustor end or tip of fuel injection nozzles by dumping the spent cooling air directly into combustion zone where it can adversely affect the combustion process in general, and NOx and CO emissions in particular. The present system or structure for cooling a combustor end or tip uses a circulating device which in this application is an annular groove positioned in the tip through which fuel is circulated and absorbs heat directly from the tip and indirectly from the combusting gases being produced in the combustion zone. After cooling the tip the fuel exits into a mixing chamber. The mixture of fuel and combustion air is then introduced into the combustion zone, thus, avoiding the direct injection of fuel into the combustion zone. The fuel enters an inlet opening and exits an outlet opening which are positioned about 180 degrees one from the other.

Injector tip cooling using fuel as the coolant

Past systems have attempted to provide a combustion system to reduce NOx pollution, however, such methods have failed to attain adequate reductions in NOx pollution. The present system or structure for for reducing NOx includes a pilot fuel system and a premixed supply system to reduce the NOx to a workable level. The pilot system uses a device for supplying combustible fuel to the fuel injection nozzle generally along a combustion axis during all or a portion of the operating conditions of the engine. Low NOx is maintained by using a device for supplying combustible fuel into each of a plurality of spaces formed between a plurality of swirler vanes. Low NOx is further maintained by having the cooling fluid used to cool the fuel injection nozzle mixed with the fuel and air from the spaces prior to entering the combustion chamber.

Lean premix combustor system

The lean premix combustion approach for NOx emissions control in gas turbine combustion systems has led to the problems of increased combustion pressure oscillation during engine operation and flame outs during rapid engine load reduction. Combustion pressure oscillation can reduce the durability of the engine and combustion system components to unacceptable levels. Flame outs can make the engine unacceptable from the operational viewpoint. The use of a control device allows the combustion pressure oscillation amplitude to be controlled to levels required for long durability of the combustion system components. It also allows an engine control system to operate the engine at part load condition and during rapid load reduction without flame out. When used at small levels, its effect on the engine NOx emissions is small. Higher levels may sometimes be needed to control the combustion pressure oscillation to acceptable levels. In such a situation, the penalty of increased NOx emissions has to be accepted in order to have an operationally acceptable engine.

Lean premix combustion system having reduced combustion pressure

The present system or structure for cooling a combustion end of a fuel injection nozzle is accomplished by providing a cooling passage for skin cooling of the portion of the nozzle directly exposed to the combustion flames. A twofold path is provided through which cooling air can enter cooling passages and cool an end portion of a second member and a tip. A first flow path is intended to primarily cool the tip and further cool the end portion. A second flow path is intended to ensure primary cooling of the end portion Thus the combustor end of the fuel injection nozzle is maintained at a temperature low enough to prevent failure of the combustor end through oxidation, cracking and buckling. Both the cooling flow paths dump the spent air in a cavity formed between the injector nozzle and a combustor. The spent cooling air becomes a part of the main combustion air and, therefore, does not adversely affect the combustion process in general and NOx and CO emissions in particular. Low NOx is further maintained by using a device for supplying combustible fuel into each of a plurality of spaces formed between a plurality of radial swirler vanes.

Fuel injection nozzle having tip cooling

Past systems have attempted to cool the combustor end or tip of fuel injection nozzles, however, such methods have failed to attain adequate cooling and life. The present system or structure for cooling a tip or combustion end of a fuel injection nozzle is accomplished with a twofold structure. First, a plurality of openings being acutely positioned in the combustor end about a plurality of base circles provide effective air-sweep cooling. Secondly, the convection cooling of a back face and a combustion face provides effective convection cooling. The two structures are combined to provide an effective, efficient cooling of the combustor end or tip. The combustor end of the fuel injection nozzle is maintained at a temperature low enough to prevent failure of the combustor end through oxidation, cracking and buckling and the air-sweep avoids carbon deposits on the combustor face.

Injection nozzle tip cooling

The use of water injection for reduction of NOx emissions in gas turbine engines is well known. Many of the injectors used to supply water to the combustion chamber have used existing dual fuel injectors which are expensive, provide poor mixing, combustion and ineffective water conservation. The present gaseous fuel injector includes a device to cause the swirling of water at an outlet end of the injector, a plurality of tangentially angled passages to cause the swirling of the gaseous fuel and a device for directing a portion of the air into contact with the flow of fuel prior to entering the combustor section. The swirling of the water, gaseous fuel and the air are in the same direction and are all aerodynamically additive resulting in an efficient low cost gaseous fuel injector to reduce NOx emissions.

Gaseous fuel injector

Systems capable of supplying either all gaseous fuel, all liquid fuel, or a mixture of the two, at a preselected ratio have been successfully employed in gas turbine engines. The mixing of such fuels has taken place in the combustion chamber and has caused the nozzle design and system controls to complicate the structure and increase costs. The subject system for burning gaseous fuels having a range of calorific values has overcome these problems by providing a simple inexpensive system. The system uses a starting step where only high calorific value gaseous fuel is injected through a first fuel supply passage of an injector and operates the engine to a preestablished engine operating parameter. After the preestablished engine operating parameter has been reached a low calorific value gaseous fuel is mixed in a mixing chamber outside the combustion chamber and injected through the first fuel supply passage until a level of heating value of the mixed fuel or a second engine operating parameter has been reached. The mixing continues and a second fuel supply passage of the injector is opened to increase the mass/volume flow of fuel into the engine. The ratio of low calorific value gaseous fuel increases and the high calorific value gaseous fuel decreases as the engine operating parameters are monitored until the engine operates on only the low calorific value gaseous fuel.

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Encinitas, CA, United States of America

Virendra M Sood