Variable Area Nozzle Gas Turbine for Block Loading
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Solution Overview
Problem
Gas turbines, particularly free-power turbine engines, exhibit poor transient behavior and part-load efficiency, making them unsuitable for off-grid power generation that requires high reliability and power quality, especially under block-loading conditions.
Innovation Solution
A multi-spool gas turbine engine design incorporating a free power turbine with a variable area nozzle, a high-speed alternator, active rectifier, inverter, and ultra-capacitors, along with a fast-acting fuel valve and actuator, to achieve rapid control over gas flow and temperature, reducing turbo-lag and maintaining ISO-qualified power quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a free-power turbine engine is used, then part-load efficiency is improved, but transient behavior deteriorates
Solution Approach 1:
The patent applies dynamics by making the nozzle area variable rather than fixed. The variable area nozzle can dynamically adjust its opening area in response to load changes, allowing the free-power turbine to maintain optimal performance across different operating conditions. This dynamic adjustment resolves the contradiction by enabling both good part-load efficiency (through optimized nozzle area) and good transient behavior (through rapid area adjustment capability).
Solution Approach 2:
The patent changes the parameter of nozzle area from fixed to variable. By controlling the nozzle area as a可调 parameter, the system can optimize gas flow and power output for both steady-state part-load operation and transient block-loading conditions. This parameter change allows the engine to adapt to different operating requirements, resolving the contradiction between efficiency and transient response.
2Reliability
If a single shaft engine is used, then transient behavior under block-loading is improved, but part-load efficiency deteriorates
Solution Approach 1:
The patent segments the gas turbine system into independent components: a fixed nozzle for the upstream turbines and a variable area nozzle for the free-power turbine. This segmentation allows each section to be optimized independently - the upstream section provides stable transient response while the free-power turbine section with variable nozzle maximizes part-load efficiency. The segmentation resolves the contradiction by decoupling the functional requirements of different operating conditions.
3Speed
If a variable area nozzle is added to the free power turbine, then transient response is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical nozzle control systems with alternative actuation methods. The variable area nozzle can be controlled through pneumatic actuators, electronic control systems, or other non-mechanical means, reducing mechanical complexity while maintaining rapid response capability. This substitution resolves the contradiction by achieving fast transient response without proportionally increasing device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The engine achieves exceptional transient response and high efficiency at part-load conditions, minimizing emissions and ensuring reliable power delivery with agile control over volatile load shifts, enabling independent operation of modern data centers and other off-grid applications.
Implementation Method 1
The free power turbine is, in some embodiments, fitted with a variable area nozzle to enable rapid response control of the gas flow and temperature at fractional power
Implementation Method 2
An array of ultra-capacitors may be connected to a DC circuit between the active rectifier and the inverter to provide a transient power boost during block loading
Implementation Method 3
Solar photovoltaic arrays or other renewable energy sources may also be connected to such a DC circuit
Implementation Method 4
A gas turbine engine in some embodiments comprises one or more turbo-compressor spools wherein each spool comprises a compressor, a turbine, and a first rotatable shaft
Implementation Method 5
The free power turbine may be connected to a high speed alternator which, in turn, may be connected to an active rectifier
Data Source
AI summary
An apparatus and method are disclosed that enable a multi-spool gas turbine engine to produce ISO-qualified power quality during block loading, while also achieving high efficiency over a wide power range. Such an engine would enable new markets, including modern data centers, to operate independently from the utility grid, while achieving high efficiency, reliability, and power quality. The engine includes a variable area nozzle upstream of the free power turbine. On experiencing the torque spike, the variable area nozzle is opened rapidly to provide rapid an increase in air flow aspirated by the engine. When combined with a proportionally increased fuel supply, the power and torque of the free power turbine increases with a time constant close to that of the fuel valve and variable area nozzle movement. Coupling a variable speed alternator to the free power turbine, and coupling the rectified alternator output to an inverter serves to isolate the speed change of the alternator from the frequency delivered to the power grid.