Prime-mover dynamo plants – Turbogenerators
Reexamination Certificate
2001-08-24
2003-04-08
Ponomarenko, Nicholas (Department: 2834)
Prime-mover dynamo plants
Turbogenerators
C322S037000, C060S660000
Reexamination Certificate
active
06545373
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to turbo-generators, and more particularly to control mechanisms and methods to provide balanced loading for a turbo-generator's turbine.
BACKGROUND OF THE INVENTION
The use of electronics and electronic equipment in modern aircraft, and in particular modern jet fighter aircraft, continues to increase. Flight control computers, communications equipment, radar equipment, electronic defense systems, electronic targeting systems, etc. all require electric power to operate. Indeed, some of these systems require an exceedingly large amount of electric power to perform their function. Unfortunately, along with high power consumption comes high heat generation and dissipation.
While dealing with high heat generation is troublesome in any system, airborne applications present additional, unique challenges to this problem. Specifically, the complexity of control and sophistication of the electronics on modern aircraft are particularly susceptible to high operating temperatures, and therefore it becomes crucial to provide cooling so that these sophisticated electronics may continue to operate reliably. Further, since each additional pound of weight translates directly to increased fuel burn and therefore decreased range, the electronic subsystems are designed to be as compact and lightweight as possible. Such compact, lightweight design results in increased power densities among the electronic components. Unfortunately, devices with this increased power density typically have a much reduced surface area from which the heat may be removed. As the processing speed of these components increases, the increased switching rate multiplies the switching losses inherent in the devices such that the temperature rise becomes significant over the same period of time as compared to a slower processing component. Unfortunately, despite the fact that all of these factors combined to require a much larger capacity cooling system, the relationship between increased weight and reduced range for an aircraft counters the desirability of adding larger cooling systems.
In an attempt to meet the increased cooling requirements driven by the sophistication, size, and power density of the modern electronic equipment, some systems have reverted to the use of ram air cooling of the electronic components. Unfortunately, the introduction of ram air into the aircraft increases the drag on the aircraft, and therefore reduces the effective range of that aircraft proportionally. While self-contained liquid cooling systems may be used to adequately remove the heat generated by the electronic components, the weight and complexity of such systems provides a disincentive for their use. However, to enable the sophisticated electronics to continue to operate, such systems are typically employed, despite the impact on range and fuel consumption. Even in these systems, however, some type of cooling air is often needed to remove the heat from the liquid coolant.
While the initial design of a modern aircraft may take into account the necessary cooling systems to remove the heat generated by the sophisticated modern electronic subsystems included therein, a unique problem is presented by such modern electronics for older, existing air frames. That is, because an airframe has a useful service life of many years or decades, the subsequent development of highly sophisticated electronic subsystems often presents an opportunity to retrofit the existing airframe to provide enhanced functionality and sophistication. Unfortunately, the originally designed cooling system on the older aircraft may not have the capacity to dissipate the heat generated by the newer electronic subsystems. In such cases the retrofit activity must also include a retrofit of the existing cooling system and/or electric power generating system, which often significantly adds to the cost and detracts from the desirability of conducting such retrofit. As with the original design trades, consideration of ram air, liquid, or some other cooling system must take place. Because it is not desirable to allow such retrofits to significantly reduce the range of the existing airframe, such a cooling system must not significantly add to the drag of the aircraft nor add unnecessary weight and complexity to the aircraft. Such design considerations generally preclude the usage of ram air.
One cooling system that is capable of providing the additional cooling required by the usage of modern sophisticated electronics and electronic subsystems uses an expansion turbine driven by a source of gas, such as, e.g., bleed air from the main engine of the aircraft. Such a cooling system operates by directing bleed air from the engine through an expansion turbine to significantly cool the bleed air. This cooled air output from the expansion turbine is then passed across heat exchangers that remove the heat from the electronic components and subsystems to allow them to operate properly. Unfortunately, for the expansion turbine to provide the necessary cooling of the bleed inlet air, the turbine must be loaded. One method known to provide such turbine loading is to couple an electric power generator to the expansion turbine shaft and couple the electric power output to the utilization equipment to supply power thereto. Unfortunately, the required loading on the turbine is primarily driven by the requirement for cooling, not by the electrical needs of utilization equipment.
However, typical turbine driven generator control systems do not operate in a fashion that controls the increase or decrease of generator output to supply a required amount of loading on the turbine to allow the turbine to provide the required amount of cooling. In fact, typical generator controls systems would tend to unload the turbine to maintain output electrical regulation by reducing the excitation of the generator as the turbine sped up to meet an increased thermal demand. This, however, is completely opposite to the achievement of enhanced cooling capacity through the expansion turbine. That is, as an increased flow is demanded by the cooling system, the speed of the turbine will increase. This increase in generator input speed will be compensated by the generator control system by reducing generator excitation in an attempt to maintain the same output power to the connected utilization equipment. Furthermore, operation of the utilization equipment may well result in the expansion turbine being unable to meet its cooling requirement on a steady state basis. That is, if the utilization equipment powered from the turbine driven generator is reduced based on the utilization equipment operating profiles, this will in turn reduce the loading of the expansion turbine, which will result in a proportional reduction in the ability of the expansion turbine to cool the engine bleed air. This will, in turn, reduce the ability of the expansion turbine to provide the required cooling for which it was designed.
In view of these significant problems, expansion turbine driven generators, also known as turbo-generators, are not typically used to provide cooling despite the apparent advantages of its size, weight over other systems.
There exists, therefore, a need in the art for a system that coordinates the turbine loading provided by an electrical generator with the cooling requirements for which it is installed.
BRIEF SUMMARY OF THE INVENTION
In view of the above, it is an object of the present invention to provide a new and improved ballast loading system and method. More specifically, it is an object of the present invention to provide a new and improved ballast loading system and method for a turbo-generator that provides relatively consistent, balanced loading on the turbine. When such a system as presented by the present invention is utilized in an application that requires the turbo-generator to supply cooling through the turbine and electric power from the generator, consistent turbine loading to meet the cooling requirements is provided by the generator ball
Andres Mike
Brady Daniel E.
Temple Terry
Leydig , Voit & Mayer, Ltd.
Ponomarenko Nicholas
Smiths Aerospace, Inc.
LandOfFree
System and method for providing ballast loading for a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with System and method for providing ballast loading for a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and System and method for providing ballast loading for a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3043345