High power density microturbine generator and method of generating power

Abstract

High power density micro gas turbine generator and power generation method, the generator includes turbocharger, combustion chamber, generator, coupling and heat exchanger; turbocharger includes core engine, pressure shell assembly and volute assembly; core engine includes main shaft, turbine, bearing inner ring related assembly, impeller, support shell assembly, bearing outer ring related assembly and shafting vibration damping assembly; the coupling is connected with the main shaft impeller mounting section and the generator rotor respectively at both ends; the exhaust gas inlet of the heat exchanger is communicated with the exhaust gas outlet A of the volute; the exhaust gas outlet B of the heat exchanger is communicated with the atmosphere.The power generation method is applied to high power density micro gas turbine generator, and the steps are as follows: integrated starting; combustion condition switching; turbine vibration reduction control; gas compression heat recovery; coaxial power output; working condition self-adaptive adjustment.The application has the advantages that the turbocharger is expanded from the function of energy recovery component to the function of active power output assembly.

Description

Technical Field

[0001] This invention relates to the field of turbocharger power generation technology, and in particular to a high power density micro gas turbine generator and power generation method. Background Technology

[0002] With the rapid development of new energy vehicles, low-altitude aircraft, and distributed mobile energy, the demand for high power density, multi-fuel adaptability, and lightweight power generation devices is becoming increasingly urgent. Micro gas turbine generators, as a type of small distributed energy system, have advantages such as high energy utilization, low environmental pollution, fast start-up speed, and wide fuel adaptability (they can use natural gas, hydrogen, diesel, and aviation kerosene, etc.), and are considered an ideal solution for next-generation hybrid vehicle range extenders, mobile emergency power supplies, and special equipment power.

[0003] Currently, most commercially available micro gas turbine generators utilize axial-flow or radial-flow gas turbine technology, with a single unit power typically exceeding 30kW. These generators are also characterized by complex structures and large sizes. The complex aerodynamic structures and precision machining requirements of these traditional devices generally result in high manufacturing costs, and their large size and weight make it difficult to meet the power density requirements of vehicles such as passenger cars and drones, which have stringent space and load constraints. To reduce costs and size, the industry has seen attempts to convert automotive exhaust gas turbochargers into power generation devices.

[0004] Existing technologies mostly utilize engine exhaust to drive turbines for power generation, falling under the category of waste energy recovery and unable to operate independently as a primary power source. Furthermore, the traditional shaft system structure employing floating bearings and thrust bearings has the following inherent defects, making it difficult to adapt to the high-speed and high-stability requirements of active power generation: 1. Difficulty in controlling the shaft's motion trajectory: Floating bearings are essentially hydrodynamic lubricated bearings, and the rotor has a large radial clearance within the bearing bore. Under high-speed operation and varying operating conditions, the rotor shaft is prone to significant drift and sway, leading to increased shaft vibration and making it difficult to meet the requirements of high-speed rotors for operational stability and concentricity.

[0005] 2. Inappropriate critical speed design: Existing shaft systems typically lack effective elastic damping support structures, resulting in high bending stiffness of the shaft system. The critical speed often falls within the turbocharger's operating speed range (i.e., "hard-support" mode). When the rotor speed approaches the critical speed, the system will experience severe resonance, greatly increasing the risk of shaft fatigue fracture and limiting the development of turbochargers to higher speeds.

[0006] 3. Unstable power output at the pressure end: Traditional turbochargers only drive the compressor impeller, and their pressure end lacks reliable axial positioning and power output interface. Due to the weak axial load capacity of floating bearings and the large axial runout of the shaft system, it is impossible to connect loads such as generators to the pressure end for power output. Even if a connection is forced, coupling damage caused by radial runout or uneven air gap in the generator can easily occur, leading to rotor rubbing accidents.

[0007] To address these shortcomings, the industry has attempted optimizations such as improving bearing arrangement or introducing air foil bearings. However, these solutions often suffer from complex structures and excessive costs, and still cannot simultaneously ensure the dynamic stability of the shaft system and the compatibility of the pressure-end power output interface. Furthermore, existing solutions generally lack adaptive designs for multi-fuel combustion fluctuations, making it difficult to guarantee operational stability during fuel switching.

[0008] In summary, existing micro gas turbine generators generally suffer from low volumetric power density and high cost. Furthermore, generators based on modified traditional turbochargers exhibit insurmountable deficiencies in shaft system dynamic stability, critical speed avoidance, and power output interface, and cannot adapt to combustion fluctuations under multi-fuel operating conditions. Therefore, a novel micro gas turbine generator structure is urgently needed, particularly an improvement to its core turbocharger assembly, to address these technical challenges and meet the application requirements of next-generation mobile energy equipment. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high power density micro gas turbine generator and power generation method. It solves the problems of existing micro gas turbine generators, such as complex structure, large size, high cost, shaft instability of traditional modified turbochargers, difficulty in power output at the pressure end, low assembly reliability, poor multi-fuel compatibility of existing improved solutions, and difficulty in using them as independent active power sources.

[0010] The technical solution of this invention is: a high power density micro gas turbine generator, comprising a turbocharger, a combustion chamber, a generator, a coupling, and a heat exchanger; A turbocharger consists of a core, a pressure housing assembly, and a turbine housing assembly. The core unit includes a main shaft, a turbine, bearing inner ring components, an impeller, a support housing assembly, bearing outer ring components, and a shaft vibration damping assembly. The main shaft has a vortex end and a pressure end at its two ends. From the pressure end to the vortex end, the main shaft has an impeller mounting section, an intermediate section, and a turbine connecting section with progressively increasing shaft diameters. An annular stepped surface A is provided between the intermediate section and the turbine connecting section. The turbine is fixed to the end face of the turbine connecting section of the main shaft. The bearing inner ring components are fitted onto the intermediate section of the main shaft. The impeller is mounted on the impeller mounting section of the main shaft. The support housing assembly includes a bearing body; the end face of the bearing body facing the impeller is the pressure end end face, and the end face of the bearing body facing the turbine is the vortex end end face. The bearing outer ring components include a bearing outer ring A, a bearing outer ring B, and a wave spring for providing preload. The shaft vibration damping assembly includes a vortex end elastic ring and a pressure end elastic ring. The vortex end elastic ring is installed between the bearing outer ring A and the bearing body; the pressure end elastic ring is installed between the bearing outer ring B and the bearing body. The pressure housing assembly includes a pressure housing and a blade diffuser; the pressure housing has a cavity X inside for accommodating the impeller, and a first fixed part and a second fixed part arranged opposite to each other on the outside of the pressure housing, as well as an air inlet B and an air outlet B for air to enter and exit; the pressure housing also has a first insertion part arranged concentrically with the first fixed part; the pressure housing is fixedly connected to the pressure end face of the bearing body through the second fixed part; the air inlet B of the pressure housing is in communication with the atmosphere; the blade diffuser is installed inside the cavity X and is arranged around the circumferential outer side of the impeller for diffuser and pressurize the high-speed airflow thrown out by the impeller; The volute assembly includes a volute and a turbine guide; the volute has an internal cavity Y for accommodating the turbine, an external third fixed part, an exhaust outlet A for discharging exhaust gas, and a gas inlet for entering the combustion gas; the volute is fixedly connected to the volute end face of the bearing housing through the third fixed part; the turbine guide is installed in the cavity Y and located upstream of the turbine along the direction of combustion gas flow. The combustion chamber is equipped with a premixing chamber and a combustion chamber that are interconnected. The bottom of the combustion chamber is equipped with a fuel inlet that connects to the premixing chamber. The side wall of the combustion chamber is equipped with an air inlet A that connects to the premixing chamber. The top of the combustion chamber is equipped with a gas outlet that connects to the combustion chamber. An igniter is fixedly installed on the outer side wall of the combustion chamber. The gas outlet of the combustion chamber is connected to the gas inlet of the volute. The generator includes a stator and a rotor; the rotor is rotatably installed in the inner cavity of the stator; a second plug-in part and a fifth fixed part are provided on one end face of the stator; the stator is plugged into the first plug-in part of the pressure shell through the second plug-in part with a clearance fit; the stator is fixedly connected to the first fixed part of the pressure shell through the fifth fixed part. One end of the coupling is connected to the main shaft impeller mounting section, and the other end is connected to the generator rotor, thereby transmitting the torque of the main shaft to the rotor; The heat exchanger has internally separate tube cavities and shell cavities. Externally, the heat exchanger has an air inlet C and an air outlet C connected to the tube cavities, and an exhaust gas inlet B and an exhaust gas outlet B connected to the shell cavity. The air outlet C of the heat exchanger is connected to the air inlet A of the combustion chamber. The air inlet C of the heat exchanger is connected to the air outlet B of the pressure shell. The exhaust gas inlet of the heat exchanger is connected to the exhaust gas outlet A of the volute. The exhaust gas outlet B of the heat exchanger is connected to the atmosphere.

[0011] A further technical solution of the present invention is: the bearing inner ring related components include a pressure end sealing bushing, an angular contact ball bearing B, an inter-bearing bushing and an angular contact ball bearing A arranged sequentially and adjacently from the pressure end to the volute end of the main shaft; the inner rings of the angular contact ball bearing A and the angular contact ball bearing B are respectively fixed relative to the middle section of the main shaft; The impeller is mounted on the impeller mounting section of the main shaft. Its end face near the pressure end is positioned, and its end face near the vortex end abuts against the pressure end sealing sleeve, thereby causing the pressure end sealing sleeve-angular contact ball bearing B-bearing sleeve-angular contact ball bearing A to be tightly pressed against the annular step surface A of the main shaft in sequence. The supporting housing assembly also includes a volute end cap and a pressure end cap; the bearing body has an internal mounting channel that runs through both ends of the bearing body, and the mounting channel has a wave spring abutment surface A and a wave spring abutment surface B. The mounting channel accommodates the bearing inner ring related components and the bearing outer ring related components; the inner hole seal of the volute end cap is rotatably mounted on the spindle turbine connecting section and is fixedly connected to the volute end face of the bearing body; the inner hole seal of the pressure end cap is rotatably mounted on the pressure end sealing bushing and is fixedly connected to the pressure end face of the bearing body. The wave springs in the bearing outer ring assembly include wave spring A and wave spring B; bearing outer ring A is locked integrally with the scroll end cap, and bearing outer ring B is locked integrally with the pressure end cap; bearing outer ring A is fixedly fitted onto the outer ring of angular contact ball bearing A and abuts against the end face of the outer ring of angular contact ball bearing A; bearing outer ring B is fixedly fitted onto the outer ring of angular contact ball bearing B and abuts against the end face of the outer ring of angular contact ball bearing B; both wave spring A and wave spring B are fitted onto the bearing bushing; wave spring A is compressed and positioned between the wave spring abutting surface A and the end face of bearing outer ring A, providing preload force for angular contact ball bearing A; wave spring B is compressed and positioned between the wave spring abutting surface B and the end face of bearing outer ring B, providing preload force for angular contact ball bearing B; The vortex end elastic ring in the shaft vibration damping assembly is installed between the outer circular surface of the bearing outer ring A and the inner wall of the mounting channel, and is positioned circumferentially and axially, and is relatively fixed to the inner wall of the mounting channel; the pressure end elastic ring in the shaft vibration damping assembly is installed between the outer circular surface of the bearing outer ring B and the inner wall of the mounting channel, and is positioned axially and circumferentially, and is relatively fixed to the inner wall of the mounting channel.

[0012] A further technical solution of the present invention is as follows: A spline sleeve is fixedly connected to the end face of the main shaft impeller mounting section by a shaft locking screw. The outer circular surface of the spline sleeve is provided with an impeller positioning surface. The spline sleeve is provided with a stepped bolt hole that passes through both ends of the spline sleeve. The stepped bolt hole includes a first hole section that is relatively far away from the main shaft and a second hole section that is relatively close to the main shaft. The first hole section is provided with an internal spline A for power output. The end face of the main shaft impeller mounting section is provided with an internal thread hole corresponding to the stepped bolt hole. The shaft locking screw passes through the stepped bolt hole and is screwed into the internal thread hole, thereby fixing the spline sleeve axially. Then, the spline sleeve sequentially presses the impeller-pressure end sealing sleeve-angular contact ball bearing B-bearing inter-sleeve-angular contact ball bearing A onto the annular step surface A of the main shaft. At the same time, the bearing outer ring A and the bearing outer ring B respectively maintain the preload of the wave spring A and the wave spring B. The rotor is provided with an internal spline B, and the center line of the internal spline B coincides with the center line of the rotor shaft. The coupling has external splines with drum-shaped teeth at both ends. The coupling is connected to the internal spline A of the spline sleeve and the internal spline B of the rotor through the external splines with drum-shaped teeth at both ends.

[0013] A further technical solution of the present invention is as follows: the structure of the vortex end elastic ring and the pressure end elastic ring is completely identical; both are made of spring steel and are integrally formed circular ring components; both include a circular ring body, with multiple outer arc protrusions evenly distributed in a ring on the outer circular surface of the circular ring body, and multiple inner arc protrusions evenly distributed in a ring on the inner wall of the circular ring body, the length directions of the outer arc protrusions and inner arc protrusions being parallel to the axial direction of the circular ring body; all outer arc protrusions and all inner arc protrusions are staggered; the convex arc surface between the two sides of the length direction of the outer arc protrusion is defined as the outer working surface, and the concave arc surface between the two sides of the length direction of the inner arc protrusion is defined as the inner working surface; all outer working surfaces share an annular surface A, all inner working surfaces share an annular surface B, and annular surface A, annular surface B, the outer circular surface of the circular ring body, and the inner wall of the circular ring body are coaxial; after the circular ring body is assembled, all outer working surfaces simultaneously make close contact with the inner wall of the bearing housing mounting channel, and all inner working surfaces simultaneously form a clearance fit with the outer circular surface of the bearing outer ring A or the outer circular surface of the bearing outer ring B.

[0014] A further technical solution of the present invention is: a pin hole A is provided on the ring body; correspondingly, a pin hole X corresponding to the position of pin hole A is provided on the bearing outer ring A or bearing outer ring B; after the ring body is assembled, the ring body and bearing outer ring A are locked together by passing a locking pin through pin hole A and pin hole X, or the ring body and bearing outer ring B are locked together, thereby restricting the circumferential movement of the ring body. The number of outer arc protrusions and inner arc protrusions are 4-8 each, and the number of outer arc protrusions is the same as the number of inner arc protrusions; the outer working surface of the outer arc protrusion occupies the central angle α, and the inner working surface of the inner arc protrusion occupies the central angle β. The value range of central angle α is 5-15°, and the value range of central angle β is 5-15°. The interval central angle γ between any adjacent central angle α and central angle β is the same. Within the complete circumference angle of the annular body, all central angle α and all central angle β do not overlap, so that central angle α and central angle β are alternately arranged within a complete circumference angle. Both sides of the outer arc protrusion along its length direction are smoothly transitioned to the outer circular surface of the ring body through an arc ramp A, and both sides of the inner arc protrusion along its length direction are smoothly transitioned to the inner wall of the ring body through an arc ramp B; both ends of the outer arc protrusion along its length direction are provided with an outer chamfered surface for a smooth transition between the end face of the ring body and the end face of the ring body, and both ends of the inner arc protrusion along its length direction are provided with an inner chamfered surface for a smooth transition between the end face of the ring body and the end face of the ring body. The thickness S1 of the ring body is defined as the difference between the outer radius of the ring body and the inner radius of the ring body, with a value range of 1-1.5mm; the thickness S2 of the outer arc protrusion is defined as the difference between the radius of the annular surface A and the outer radius of the ring body, with a value range of 0.13-0.2 times S1; the thickness S3 of the inner arc protrusion is defined as the difference between the radius of the inner hole of the ring body and the radius of the annular surface B, with a value range of 0.13-0.2 times S1.

[0015] A further technical solution of the present invention is: the section corresponding to the bushing between the spindle and the bearing is provided with an assembly process section, which includes a reduced diameter section and tapered transition sections at both ends of the reduced diameter section. The two tapered transition sections are used to smoothly connect the reduced diameter section with the standard outer diameter section of the middle section. The initial assembly compression of wave spring B is greater than that of wave spring A, so that both angular contact ball bearing A and angular contact ball bearing B can maintain a controlled positive preload. The inner holes of bearing outer ring A and bearing outer ring B are respectively provided with outer ring positioning surface A and outer ring positioning surface B; bearing outer ring A abuts against the outer ring end face of angular contact ball bearing A through outer ring positioning surface A; bearing outer ring B abuts against the outer ring end face of angular contact ball bearing B through outer ring positioning surface B.

[0016] The technical solution of this invention is: a high power density micro gas turbine power generation method, applied to the above-mentioned high power density micro gas turbine generator, the steps of which are as follows: S1. Start-up and start-up in one: The generator's working state is switched by the controller corresponding to the generator, and the generator's start-up and start-up characteristics are called to make it run in motor mode: The controller inverts DC power into AC power and inputs it into the stator windings to drive the rotor to output torque, which drives the main shaft to rotate through the coupling, dragging the turbocharger to the preset ignition and combustion speed threshold. During this process, the following two things happen simultaneously: Ⅰ. The impeller in the pressure chamber X rotates synchronously with the main shaft, drawing in filtered outside air from the air inlet B and compressing it through the impeller to generate compressed air for initial combustion. The compressed air enters the premixing chamber through the air inlet A; Ⅱ. Ignition fuel is supplied to the igniter and power is supplied. Based on the above synchronization, the igniter generates ignition energy to ignite the gas mixture in the premix chamber, thereby establishing initial combustion; S2. Combustion mode switching: After detecting that the temperature at the gas outlet reaches the preset switching threshold, the initial combustion is determined to be stable; then, power generation fuel is continuously supplied to the fuel inlet, and the supply of ignition fuel is maintained to keep the flame stable; the power generation fuel is mixed with the compressed air in the premixing chamber and burned in the combustion chamber to generate working gas for driving the turbine; the power generation fuel supply is gradually increased, and the turbine is driven by the generated working gas, so that the main shaft speed is gradually increased; after the power generation fuel combustion is stable, the ignition fuel supply is cut off; when the main shaft speed reaches the preset self-sustaining combustion speed threshold, the controller switches the generator to power generation mode; S3. Turbine vibration control: The working gas is discharged from the gas outlet of the combustion chamber, enters the cavity Y of the volute through the gas inlet, and is rectified by the turbine guide to impact the turbine blades, driving the main shaft into a self-sustaining rotation state. The exhaust gas after doing work is discharged from the exhaust gas outlet A of the volute, and then enters the shell cavity of the heat exchanger through the exhaust gas inlet to provide a heat source for subsequent heat recovery. During spindle operation, the back-to-back arrangement of angular contact ball bearings A and B restricts spindle axis drift. Wave springs A and B apply preload to angular contact ball bearings A and B respectively to suppress axial movement of the spindle and eliminate internal clearance of angular contact ball bearings A and B. When the spindle vibrates due to unbalanced centrifugal force or airflow pulsation, the volute end elastic ring and the pressure end elastic ring undergo controllable elastic deformation to absorb vibration energy and reduce shaft bending stiffness. This adjusts the critical speed of the spindle to outside the operating speed range, eliminating the risk of resonance of the spindle in the entire operating speed range. S4. Compressed Air Heat Recovery: When the main shaft rotates, it drives the impeller to rotate synchronously. The filtered air is drawn into the pressure shell cavity X through the air inlet B. After being compressed by the impeller and pressurized by the blade booster, it forms compressed air. The compressed air is discharged from the air outlet B and then enters the tube cavity of the heat exchanger through the air inlet C. It exchanges heat with the exhaust gas from the volute exhaust gas outlet A in the heat exchanger shell cavity. After absorbing heat and heating up, it is discharged through the air outlet C and enters the premixing cavity through the air inlet A of the combustion chamber to participate in fuel blending. S5. Coaxial power output: When the main shaft is in a self-sustaining rotation state, its torque is transmitted to the generator rotor through the coupling; the stator is fitted with the first insertion part of the pressure shell through the second insertion part, which restricts the relative position of the stator and the pressure shell, ensuring that the rotor axis coincides with the main shaft axis, and avoiding the rubbing failure caused by uneven air gap between the generator rotor and stator; the rotor rotates in the stator cavity and cuts the magnetic field lines to generate an induced electromotive force, which is rectified and regulated by the controller before outputting electrical energy; S6. Adaptive Adjustment of Operating Conditions: After the main shaft enters the self-sustaining rotation state, the supply of fuel for power generation is gradually increased, causing the main shaft speed to gradually increase to the rated power generation condition. During this process, the main shaft speed, shaft vibration amplitude, and combustion chamber outlet gas temperature are monitored in real time. When it is determined based on the above monitoring parameters that the preload of the angular contact ball bearings decreases due to thermal expansion or aerodynamic load, the wave spring B with a larger initial compression releases the preload reserve through its own deformation to offset the preload loss and maintain the positive preload state of the angular contact ball bearings A and B. When switching to power generation fuels with different calorific values, the pressure pulsation amplitude in the combustion chamber increases. The vortex end elastic ring and the pressure end elastic ring absorb the pulsation energy through controllable elastic deformation, suppressing the shaft vibration amplitude and ensuring the operational stability under multi-fuel conditions.

[0017] A further technical solution of the present invention is that the method further includes step S7 following step S6; S7. Shutdown Process Control: After receiving a shutdown command, the controller cuts off the fuel supply to the fuel inlet, causing the combustion chamber to shut down and the turbine to lose its driving power. After the temperature at the gas outlet drops to the preset shutdown threshold and the spindle speed drops to the preset coasting threshold, the controller switches the generator back to motor mode and applies a reverse braking current to the stator winding to smoothly drag the spindle speed to zero through energy consumption braking. The process ends after confirming that the spindle has completely stopped.

[0018] Compared with the prior art, the present invention has the following advantages: 1. High shaft running accuracy and stable and reliable power output at the pressure end: Compared with the large clearance characteristics of traditional floating bearings, the back-to-back angular contact ball bearings with wave spring preload effectively limit the radial displacement and axial movement of the main shaft, improving the rotational accuracy and rigidity of the shaft system; the pressure end is equipped with a special spline sleeve and a high-precision coaxial positioning structure (the stator is inserted into the first insertion part of the pressure shell through the second insertion part with clearance fit), eliminating the influence of internal bearing clearance, and can stably bear the additional force of the generator load, avoiding problems such as coupling damage and uneven generator air gap rubbing when the pressure end is connected to the load, realizing the functional expansion of the turbocharger from a residual energy recovery component to a main power output assembly.

[0019] 2. Low resonance risk and smooth operation across the entire speed range: To address the shortcomings of traditional shaft systems where the critical speed easily falls into the operating range under the "hard support" mode, a flexible support structure with an elastic ring is set between the bearing outer ring and the bearing body. The controllable elastic deformation of the elastic ring reduces the bending stiffness of the shaft system, adjusting the critical speed of the spindle to outside the operating speed range and avoiding the risk of resonance. The staggered convex strip arrangement design of the elastic ring can dissipate vibration energy when vibration occurs, suppress shaft vibration caused by unbalanced centrifugal force and airflow pulsation, and ensure smooth operation across the entire operating speed range.

[0020] 3. User-friendly assembly process and high reliability under all operating conditions: An assembly process section with a reduced diameter section and a tapered transition section is added to the spindle to shorten the interference fit propulsion stroke of the angular contact ball bearing, reducing assembly resistance and the risk of component damage; by differentiating the initial compression of the pressure end and the volute end wave spring, a preload compensation reserve is reserved to offset the preload loss caused by thermal expansion and aerodynamic load during operation, ensuring that the angular contact ball bearing maintains a positive preload state under all operating conditions, suppressing fretting wear, and extending the service life of the shaft system.

[0021] 4. High system integration, excellent overall energy efficiency and scenario adaptability: The turbocharger, combustion chamber, generator, and heat exchanger are integrated into one unit, eliminating the complex axial / radial aerodynamic structure of traditional micro gas turbines and effectively reducing the overall size and weight. Relying on the high rigidity support characteristics of the shaft system, it can ensure operational stability at higher operating speeds, and significantly improve the power density per unit volume. The integrated generator design eliminates the need for a separate starter motor, further simplifying the system structure. The waste heat recovery design of the heat exchanger can reduce the energy consumption of combustion chamber intake heating and improve system thermal efficiency. The damping characteristics of the elastic ring can adapt to the combustion pulsation of various calorific value fuels, breaking through the limitation of traditional modified turbochargers that can only be used for waste energy recovery, and can be adapted to various scenario requirements such as hybrid range extension and mobile emergency power supply.

[0022] The present invention will be further described below with reference to the figures and embodiments. Attached Figure Description

[0023] Figure 1This is a schematic diagram of the structure of the present invention; Figure 2 Schematic diagram of the core machine Figure I (The outer part of the bearing body is omitted; only the central area is shown.) Figure 3 Schematic diagram of the core machine Figure II (The bearing housing is shown in its entirety, omitting the impeller and turbine); Figure 4 A schematic diagram of the main shaft; Figure 5 This is a schematic diagram of the structure of the circular ring body; Figure 6 This is a three-dimensional model of the circular ring. Figure 7 This is a schematic diagram of the pressure shell assembly; Figure 8 This is a schematic diagram of the vortex shell assembly. Figure 9 for Figure 8 BB cross-sectional view; Figure 10 This is a diagram of the internal structure of the combustion chamber; Figure 11 This is a three-dimensional view of the combustion chamber; Figure 12 This is a schematic diagram of the coupling structure; Figure 13 This is a schematic diagram of the generator structure; Figure 14 This is a schematic diagram of the heat exchanger.

[0024] Special Note: Figure 5 The red and orange parts of the winning design are outer arc convex strips, while the dark green and grass green parts are inner arc convex strips.

[0025] Legend: Core machine 1; Main shaft 11; Impeller mounting section 111; Intermediate section 112; Reduced diameter section 1121; Conical transition section 1122; Turbine connecting section 113; Annular stepped surface A114; Spline sleeve 115; Internal spline A1151; Shaft locking screw 116; Internal threaded hole 117; Turbine 12; Pressure end sealing sleeve 131; Angular contact ball bearing B132; Bearing sleeve 133; Angular contact ball bearing A134; Impeller 14; Bearing body 151; Mounting channel 1511; Turbine end cover 152; Pressure end cover 153; Bearing outer ring A161; Bearing outer ring B162; Wave spring A163; Wave spring B164; Pressure shell 21; First fixed connection 211; Second fixed connection 212; Air inlet B213; Air outlet Port B214; First insertion part 215; Blade diffuser 22; Vortex casing 31; Third fixed part 311; Exhaust gas outlet A312; Gas inlet 313; Turbine guide 32; Combustion chamber 4; Premixing chamber 41; Combustion chamber 42; Fuel inlet 43; Air inlet A44; Gas outlet 45; Ignition device 46; Generator 5; Stator 51; Second insertion part 511; Fifth fixed part 512; Rotor 52; Coupling 6; Drum-shaped tooth external spline 61; Heat exchanger 7; Air inlet C71; Air outlet C72; Exhaust gas inlet 73; Exhaust gas outlet B74; Circular body 100; Outer arc protrusion 101; Inner arc protrusion 102; Pin hole A103; Circular arc ramp A104; Circular arc ramp B105; Outer chamfer surface 106; Inner chamfer surface 107. Detailed Implementation

[0026] Example 1: like Figure 1-14 As shown, the high power density micro gas turbine generator includes a turbocharger, a combustion chamber 4, a generator 5, a coupling 6, and a heat exchanger 7.

[0027] The turbocharger includes a core unit 1, a pressure housing assembly, and a turbine housing assembly.

[0028] The core machine 1 includes a main shaft 11, a turbine 12, bearing inner ring related components, an impeller 14, a support housing assembly, bearing outer ring related components, and a shaft vibration reduction assembly.

[0029] The main shaft 11 has a vortex end (right side) and a pressure end (left side) at its two ends. From the pressure end to the vortex end, the main shaft 11 has an impeller mounting section 111, an intermediate section 112, and a turbine connecting section 113 with progressively increasing shaft diameters. An annular stepped surface A114 (right side) is provided between the intermediate section 112 and the turbine connecting section 113. A spline sleeve 115 is fixedly connected to the end face of the impeller mounting section 111 of the main shaft 11 by a shaft locking screw 116. The outer circular surface of the spline sleeve 115 is provided with an impeller positioning surface.

[0030] The turbine 12 is fixed to the end face of the turbine connecting section 113 of the main shaft 11.

[0031] The bearing inner ring components include a pressure end sealing sleeve 131, an angular contact ball bearing B132 (left side), an inter-bearing sleeve 133, and an angular contact ball bearing A134 (right side), which are sequentially arranged adjacent to each other from the pressure end to the scroll end of the main shaft 11 and are fitted onto the intermediate section 112 of the main shaft 11. The inner rings of the angular contact ball bearings A134 and B132 are respectively fixed relative to the intermediate section 112 of the main shaft 11.

[0032] Impeller 14 is mounted on impeller mounting section 111 of main shaft 11. One end face of impeller 14 is pressed by impeller positioning surface of spline sleeve 115, so that the other end face of impeller 14 abuts against end face of pressure end sealing sleeve 131. Thus, pressure end sealing sleeve 131, angular contact ball bearing B132, bearing sleeve 133, and angular contact ball bearing A134 are sequentially pressed against and pressed onto the annular step surface A114 of main shaft 11.

[0033] The supporting housing assembly includes a bearing body 151, a scroll end cap 152, and a pressure end cap 153. The bearing body 151 has an internal mounting channel 1511 extending through both its two ends. The mounting channel 1511 forms a scroll end channel opening (right side) and a pressure end channel opening (left side) at both ends of the bearing body 151. The mounting channel 1511 has a wave spring abutment surface A relatively close to the scroll end of the main shaft 11 and a wave spring abutment surface B relatively close to the pressure end of the main shaft 11. The mounting channel 1511 accommodates the bearing inner ring and outer ring related components. The turbine 12 is located outside the scroll end channel opening, and the impeller 14 is located outside the pressure end channel opening. The end face of the bearing body 151 facing the impeller 14 is the pressure end face, and the end face of the bearing body 151 facing the turbine 12 is the scroll end face. The inner bore of the scroll end cap 152 is rotatably and sealingly mounted on the outer circumference of the turbine connecting section 113 of the main shaft 11 and is fixedly connected to the scroll end face of the bearing body 151. The inner hole seal of the pressure end cover 153 is rotatably mounted on the outer circular surface of the pressure end seal bushing 131 and is fixedly connected to the pressure end face of the bearing body 151.

[0034] The bearing outer ring components include bearing outer ring A161 (right side), bearing outer ring B162 (left side), wave spring A163, and wave spring B164. The inner bores of bearing outer rings A161 and B162 are respectively provided with outer ring locating surfaces A and B. Bearing outer ring A161 is locked integrally with the scroll end cap 152 (via pin), and bearing outer ring B162 is locked integrally with the pressure end cap 153 (via pin). The bearing outer ring A161 is fixedly mounted (i.e., an interference fit assembly) on the outer ring of angular contact ball bearing A134, with its inner bore's outer ring locating surface A abutting against the outer ring end face of angular contact ball bearing A134. The bearing outer ring B162 is also fixedly mounted (i.e., an interference fit assembly) on the outer ring of angular contact ball bearing B132, with its inner bore's outer ring locating surface B abutting against the outer ring end face of angular contact ball bearing B132. Both wave springs A163 and B164 are movably fitted onto the bearing sleeve 133. Wave spring A163 is compressed between the wave spring abutment surface A of the bearing housing 151 and the end face of the bearing outer ring A161. Its elastic force is transmitted to the angular contact ball bearing A134 through the bearing outer ring A161, providing preload to the angular contact ball bearing A134. Wave spring B164 is compressed between the wave spring abutment surface B of the bearing housing 151 and the end face of the bearing outer ring B162. Its elastic force is transmitted to the angular contact ball bearing B132 through the bearing outer ring B162, providing preload to the angular contact ball bearing B132.

[0035] The shaft vibration mitigation assembly includes a scroll-end elastic ring and a pressure-end elastic ring. The scroll-end elastic ring is installed between the outer surface of the bearing outer ring A161 and the inner wall of the mounting channel 1511, and is circumferentially and axially positioned (the axial positioning of the scroll-end elastic ring is achieved based on the stepped surface in the mounting channel 1511 of the bearing body 151 and the stepped surface on the outer surface of the bearing outer ring B162). It is relatively fixed to the inner wall of the mounting channel 1511 (based on an interference fit), and has a clearance fit with the outer surface of the bearing outer ring A161. The pressure-end elastic ring is installed between the outer surface of the bearing outer ring B162 and the inner wall of the mounting channel 1511, and is axially and circumferentially positioned (the axial positioning of the pressure-end elastic ring is achieved based on the stepped surface in the mounting channel 1511 of the bearing body 151 and the stepped surface on the outer surface of the bearing outer ring A161). It is relatively fixed to the inner wall of the mounting channel 1511 (based on an interference fit), and has a clearance fit with the outer surface of the bearing outer ring B162.

[0036] The pressure housing assembly includes a pressure housing 21 and a blade diffuser 22. The pressure housing 21 has an internal cavity X for accommodating the impeller 14. Externally, the pressure housing 21 has a first fixed connection 211 and a second fixed connection 212 arranged opposite to each other, as well as an air inlet B213 and an air outlet B214 for air intake and exhaust. The pressure housing 21 also has a first insertion part 215 arranged concentrically with the first fixed connection 211. The pressure housing 21 is fixedly connected to the pressure end face of the bearing housing 151 via the second fixed connection 212. The air inlet B213 of the pressure housing 21 communicates with the atmosphere to receive filtered air. The blade diffuser 22 is installed inside the cavity X of the pressure housing 21 and is arranged circumferentially around the impeller 14 to diffuse and pressurize the high-speed airflow ejected by the impeller 14.

[0037] The turbine housing assembly includes a turbine housing 31 and a turbine guide vane 32. The turbine housing 31 has an internal cavity Y for accommodating the turbine 12, and an external third fixing part 311, as well as an exhaust gas outlet A312 for discharging exhaust gas and a gas inlet 313 for entering combustion gas. The turbine housing 31 is fixedly connected to the turbine end face of the bearing housing 151 via the third fixing part 311. The turbine guide vane 32 is installed within the cavity Y of the turbine housing 31 and is located upstream of the turbine 12 along the gas flow direction, for guiding combustion gas into the turbine 12 blades.

[0038] The combustion chamber 4 has a premixing chamber 41 and a combustion chamber 42 that are interconnected. The bottom of the combustion chamber 4 has a fuel inlet 43 connected to the premixing chamber 41, and the side wall of the combustion chamber 4 has an air inlet A44 connected to the premixing chamber 41. The top of the combustion chamber 4 has a gas outlet 45 connected to the combustion chamber 42. An igniter 46 is fixedly installed on the outer wall of the combustion chamber 4 to ignite the air-fuel mixture in the premixing chamber 41. The gas outlet 45 of the combustion chamber 4 is connected to the gas inlet 313 of the volute 31.

[0039] The generator 5 includes a stator 51 and a rotor 52. The rotor 52 is rotatably mounted in the inner cavity of the stator 51. A second insertion portion 511 and a fifth fixing portion 512 are concentrically arranged on one end face of the stator 51. The stator 51 is inserted into the first insertion portion 215 of the pressure shell 21 with a clearance fit via the second insertion portion 511 to ensure the coaxiality of the rotor 52 axis with the main shaft 11 axis. The stator 51 is fixedly connected to the first fixing portion 211 of the pressure shell 21 via the fifth fixing portion 512.

[0040] One end of the coupling 6 is associated with the impeller mounting section 111 of the main shaft 11, and the other end is connected to the rotor 52 of the generator 5, thereby transmitting the torque of the main shaft 11 to the rotor 52.

[0041] The heat exchanger 7 has internally separate tube cavities and a shell cavity. Externally, it has an air inlet C71 and an air outlet C72 connected to the tube cavities, and an exhaust gas inlet 73 and an exhaust gas outlet B74 connected to the shell cavity. The air outlet C71 of the heat exchanger 7 is connected to the air inlet A44 of the combustion chamber 4. The air inlet C72 of the heat exchanger 7 is connected to the air outlet B214 of the pressure shell 21. The exhaust gas inlet 73 of the heat exchanger 7 is connected to the exhaust gas outlet A312 of the volute 31. The exhaust gas outlet B74 of the heat exchanger 7 is open to the atmosphere to discharge exhaust gas.

[0042] More specifically, the spline sleeve 115 has stepped bolt holes that pass through both ends of it. The stepped bolt holes include a first hole section that is relatively far away from the main shaft 11 and a second hole section that is relatively close to the main shaft 11. The first hole section has an internal spline A1151 for power output. The impeller mounting section 111 of the main shaft 11 has an internal threaded hole 117 corresponding to the stepped bolt hole. The shaft locking screw 116 passes through the stepped bolt hole and is screwed into the internal threaded hole 117, thereby axially fixing the spline sleeve 115 and sequentially pressing the impeller 14, the pressure end sealing sleeve 131, the angular contact ball bearing B132, the bearing inter-sleeve sleeve 133, and the angular contact ball bearing A134 onto the annular stepped surface A114 of the main shaft 11. At the same time, the preload of the wave springs A163 and B164 is maintained by the bearing outer ring A161 and the bearing outer ring B162 respectively (if the shaft locking screw is loose, the above-mentioned bearing inner ring related components will loosen and the wave spring will lose its preload function).

[0043] Correspondingly, the rotor 52 is provided with an internal spline B521, the center line of which coincides with the axis of the rotor 52.

[0044] Correspondingly, the coupling 6 is provided with drum-shaped external splines 61 at both ends. The coupling 6 is connected to the internal spline A1151 of the spline sleeve 115 and the internal spline B521 of the rotor 52 through the drum-shaped external splines 61 at both ends.

[0045] More specifically, the structures of the vortex-end elastic ring and the pressure-end elastic ring are completely identical. Both are made of spring steel and are integrally formed annular components. Both include an annular body 100, on the outer circumference of the annular body 100, multiple outer arc protrusions 101 are evenly distributed in a ring, and multiple inner arc protrusions 102 are evenly distributed in a ring on the inner wall of the annular body 100. The length directions of the outer arc protrusions 101 and the inner arc protrusions 102 are parallel to the axial direction of the annular body. All outer arc protrusions 101 and all inner arc protrusions 102 are staggered (i.e., there is no arrangement where the outer arc protrusions and inner arc protrusions are arranged vertically opposite each other). The convex arc surface between the two sides of the outer arc protrusion 101 along its length direction is defined as the outer working surface, and the concave arc surface between the two sides of the inner arc protrusion 102 along its length direction is defined as the inner working surface. All outer working surfaces share annular surface A, and all inner working surfaces share annular surface B. Annular surfaces A and B, the outer circular surface of the annular body 100, and the inner wall of the annular body 100 are coaxial. This ensures that after assembly, all outer working surfaces of the annular body 100 are in close contact with the inner wall of the mounting channel 1511 of the bearing body 151, and all inner working surfaces form a clearance fit with the outer circular surface of the bearing outer ring A161 or the outer circular surface of the bearing outer ring B162.

[0046] More specifically, the ring body 100 is provided with a pin hole A103. Correspondingly, the bearing outer ring A161 or the bearing outer ring B162 is provided with a pin hole X corresponding to the position of the pin hole A103. After the ring body 100 is assembled, the ring body 100 is locked to the bearing outer ring A161 or the bearing outer ring B162 by passing a locking pin through the pin hole A103 and the pin hole X, thereby restricting the circumferential movement of the ring body 100.

[0047] More specifically, the number of outer arc protrusions 101 and inner arc protrusions 102 are 4-8 (6 in this embodiment), and the number of outer arc protrusions 101 is the same as the number of inner arc protrusions 102. The outer working surface of the outer arc protrusion 101 occupies a central angle α, and the inner working surface of the inner arc protrusion 102 occupies a central angle β. The value range of central angle α is 5-15° (10° in this embodiment), and the value range of central angle β is 5-15° (10° in this embodiment). The interval central angle γ between any adjacent central angles α and β is the same (20° in this embodiment). Within the complete circumference (360°) of the annular body 100, all central angles α and β do not overlap, so that central angles α and β are alternately arranged within a complete circumference (i.e., each central angle α is necessarily flanked by a central angle β, and each central angle β is necessarily flanked by a central angle α).

[0048] More specifically, the two sides of the outer arc protrusion 101 along its length direction are smoothly transitioned to the outer circular surface of the ring body 100 by an arc ramp A104, and the two sides of the inner arc protrusion 102 along its length direction are smoothly transitioned to the inner wall of the ring body 100 by an arc ramp B105. Both ends of the outer arc protrusion 101 along its length direction are provided with an outer chamfered surface 106 for a smooth transition to the end face of the ring body 100, and both ends of the inner arc protrusion 102 along its length direction are provided with an inner chamfered surface 107 for a smooth transition to the end face of the ring body 100.

[0049] More specifically, the difference between the outer radius of the annular body 100 and the inner radius of the annular body 100 is defined as the thickness S1 of the annular body, and the value of S1 ranges from 1 to 1.5 mm (1.2 mm in this embodiment). The difference between the radius of the annular surface A and the outer radius of the annular body 100 is defined as the thickness S2 of the outer arc protrusion, and the value of S2 ranges from 0.13 to 0.2 times S1 (0.2 mm in this embodiment). The difference between the inner radius of the annular body 100 and the radius of the annular surface B is defined as the thickness S3 of the inner arc protrusion 102, and the value of S3 ranges from 0.13 to 0.2 times S1 (0.2 mm in this embodiment).

[0050] More specifically, the material of the ring body 100 is 60Si2MnA spring steel, which is quenched and tempered, and the stiffness of the elastic ring is 10000±100N / mm.

[0051] More specifically, the section corresponding to the bearing sleeve 133 between the main shaft 11 and the bearing is provided with an assembly process section. This assembly process section includes a reduced diameter section 1121 and tapered transition sections 1122 located at both ends of the reduced diameter section 1121. The two tapered transition sections 1122 are used to smoothly connect the reduced diameter section 1121 with the standard outer diameter section of the intermediate section 112. During installation, the angular contact ball bearing A134 is inserted from the pressure end side of the intermediate section 112, guided by the tapered transition sections 1122, crosses the reduced diameter section 1121, and is finally pushed and interference-fitted onto the standard outer diameter section of the intermediate section 112 near the turbine side. By setting the reduced diameter section 1121, the interference fit stroke and frictional resistance of the angular contact ball bearing A134 during long-distance pushing are effectively reduced, significantly reducing the assembly difficulty of the high length-to-diameter ratio main shaft when hot-fitting the bearing, and avoiding damage to the bearing inner ring and main shaft surface caused by forced pushing.

[0052] More specifically, the initial assembly compression of spring B64 is greater than that of spring A163, meaning the initial preload of spring B164 is greater than that of spring A163. This ensures that both angular contact ball bearings A134 and B132 maintain a controlled positive preload. Based on this design, the pressure end side has a larger initial preload reserve, guaranteeing that both angular contact ball bearings maintain a controlled positive preload under the combined effects of thermal expansion and aerodynamic axial loads. This improves rotor axial stiffness consistency, suppresses fretting wear, and widens the stable operating speed range. In simpler terms, the initial "tighter" spring B164 is designed to actively allocate preload margin to the side (pressure end) more easily "relaxed" by thermal deformation and axial thrust. The asymmetry in initial compression offsets the asymmetry in operating conditions, ensuring that both angular contact ball bearings always operate within the "loaded" range, without slippage, jumping, or shaking.

[0053] More specifically, the bearing housing 151 has a first positioning surface relatively close to the volute end of the main shaft 11 and a second positioning surface relatively close to the pressure end of the main shaft 11 in the mounting channel 1511. The end face of the bearing outer ring A161 near the pressure end of the main shaft 11 contacts the first positioning surface in the mounting channel 1511, and a nominal clearance of 0.1 mm is provided between the end face of the bearing outer ring B162 near the volute end of the main shaft 11 and the second positioning surface in the mounting channel 1511.

[0054] More specifically, both wave spring A163 and wave spring B164 are single-turn peak-to-valley wave springs.

[0055] More specifically, there are no design considerations for the sealing structures (such as sealing rings and sealing rings) between the components in a turbocharger, and there are no technical difficulties in implementation. Therefore, the existing sealing structures can be used as needed, and will not be elaborated here.

[0056] Briefly describe the technical effects of the turbocharger: The turbocharger adopts a three-in-one solution of "angular contact ball bearing + wave spring preload + elastic ring flexible support", replacing the floating bearing of the traditional turbocharger. It transforms the rotor from "loose and wobbly hard support" to "precisely positioned controlled flexible support", thereby solving the three major pain points of shaft drift, critical speed resonance and difficulty in pressure end power output at the same time.

[0057] Based on the aforementioned turbocharger, a method for suppressing shaft vibration can be implemented, comprising the following steps: S1. Dynamic Stress and Compression: When the spindle rotates at high speed, generating unbalanced centrifugal force or being impacted by airflow pulsations, the force is transmitted to the outer bearing ring A and the outer bearing ring B. The outer bearing ring A compresses the vortex-end elastic ring outwards, and the outer bearing ring B compresses the pressure-end elastic ring outwards. The radial clearance between the outer surface of the outer bearing ring A and the inner wall of the bearing housing mounting channel is greater than the maximum design deformation of the vortex-end elastic ring, and the radial clearance between the outer surface of the outer bearing ring B and the inner wall of the bearing housing mounting channel is greater than the maximum design deformation of the pressure-end elastic ring. This ensures that when the elastic ring is deformed under load, the outer bearing ring does not make rigid contact with the bearing housing, maintaining the flexible energy dissipation mechanism of the vibration damping ring.

[0058] S2. Elastic damping energy dissipation: The controllable elastic deformation of the circular body of the vortex end elastic ring and the pressure end elastic ring, as well as the outer arc protrusion and inner arc protrusion on them, is induced by the misalignment of the outer arc protrusion and the inner arc protrusion, thereby absorbing and damping the vibration energy.

[0059] S3. Stiffness Control and Vibration Reduction: By utilizing the flexible deformation characteristics of the vortex end elastic ring and the pressure end elastic ring, the equivalent bending stiffness of the spindle support point is reduced, thereby adjusting the critical speed of the spindle to outside the operating speed range and eliminating the risk of resonance of the spindle in the entire operating speed range.

[0060] Briefly describe the working principle of this invention: A high-power-density micro gas turbine power generation method, applied to the aforementioned high-power-density micro gas turbine generator, comprises the following steps: S1. Integrated start-up: The generator's operating state is switched by the corresponding controller, and the integrated start-up characteristic of the generator is invoked to make it run in motor mode: The controller inverts DC power into AC power and inputs it into the stator windings to drive the rotor to output torque. The torque is then driven by the coupling to rotate the main shaft, dragging the turbocharger to the preset ignition and combustion speed threshold (adjusted according to the calorific value of the generator fuel. After reaching this threshold, the turbine output power can offset the compressor power consumption and mechanical losses, without the need for continuous motor dragging).

[0061] During this process, the following two events occur simultaneously: Ⅰ. The impeller in the pressure chamber X rotates synchronously with the main shaft, drawing in filtered outside air from the air inlet B (a paper filter element with a filtration accuracy of 10μm is installed at the air inlet B to prevent impurities from damaging the impeller) and compressing it through the impeller to generate compressed air for initial combustion. The compressed air enters the premixing chamber through the air inlet A; Ⅱ. Ignition fuel (propane / hydrogen or other easily ignitable media are selected as ignition fuel, and the flow rate is 5% to 10% of the power generation fuel) is introduced into the igniter and power is supplied.

[0062] Based on the above synchronization, the igniter generates ignition energy (ignition energy ≥ 50 mJ, ignition frequency 10~20 Hz), ignites the mixed gas in the premix chamber (mixing uniformity ≥ 95%, avoiding localized oil-rich deflagration), thereby establishing initial combustion.

[0063] S2. Combustion Mode Switching: After monitoring that the temperature at the gas outlet reaches the preset switching threshold (the switching threshold is 650-850℃, and if it remains stable in this range for 3 consecutive seconds, the initial combustion is determined to be stable), the initial combustion is determined to be stable; then, power generation fuel is continuously supplied to the fuel inlet, and the supply of ignition fuel is maintained to keep the flame stable; the power generation fuel is mixed with the compressed air in the premixing chamber and burned in the combustion chamber to generate working gas for driving the turbine (combustion efficiency ≥99%, outlet gas temperature 700-950℃); the supply of power generation fuel is gradually increased, and the turbine is driven by the generated working gas, so that the main shaft speed is gradually increased; after the combustion of power generation fuel is stable, the supply of ignition fuel is cut off; when the main shaft speed reaches the preset self-sustaining combustion speed threshold, the controller switches the generator to power generation mode.

[0064] S3. Turbine vibration reduction control: The working fluid gas is discharged from the gas outlet of the combustion chamber, enters the cavity Y of the volute through the gas inlet, and is rectified by the turbine guide before impacting the turbine blades, driving the main shaft into a self-sustaining rotation state. The exhaust gas after doing work is discharged from the exhaust gas outlet A of the volute (at this time the exhaust gas temperature is 650~900℃), and then enters the shell cavity of the heat exchanger through the exhaust gas inlet to provide a heat source for subsequent heat recovery; the controller then switches the generator back to the power generation mode (switching time ≤100ms to avoid power interruption).

[0065] During spindle operation, the spindle axis drift is limited by the back-to-back arrangement of angular contact ball bearings A and B (the wide end faces of the two bearings face each other, forming an O-ring support that can withstand bidirectional axial loads). Wave springs A and B apply preload to angular contact ball bearings A and B respectively (wave spring A preload 80–120 N, wave spring B preload 120–180 N, with wave spring B having a larger preload to compensate for preload loss due to thermal expansion). If the shaft locking screws loosen, the related components of the bearing inner ring will loosen, and the wave springs will lose their preload function. Regular checking of the screw tightening is necessary. With a torque ≥25 N·m, the spindle axial movement is suppressed, and the internal clearance of angular contact ball bearings A and B is eliminated. When the spindle vibrates due to unbalanced centrifugal force or airflow pulsation, the vortex end elastic ring and the pressure end elastic ring undergo controllable elastic deformation to absorb vibration energy (the maximum design deformation of the elastic ring is 0.08~0.12 mm, avoiding rigid contact between the bearing outer ring and the bearing body, and maintaining a flexible energy dissipation mechanism). At the same time, the bending stiffness of the shaft system is reduced, and the critical speed of the spindle is adjusted to outside the operating speed range, eliminating the risk of resonance of the spindle in the entire operating speed range.

[0066] S4. Compressed Air Heat Recovery: When the main shaft rotates, it drives the impeller to rotate synchronously. The filtered air is drawn into the pressure shell cavity X through the air inlet B. After being compressed by the impeller and pressurized by the blade booster, it forms compressed air. The compressed air is discharged from the air outlet B and then enters the tube cavity of the heat exchanger through the air inlet C. It exchanges heat with the exhaust gas from the volute exhaust gas outlet in the heat exchanger shell cavity. After absorbing heat and heating up, it is discharged through the air outlet C and enters the premixing cavity through the air inlet A of the combustion chamber to participate in fuel blending.

[0067] S5. Coaxial power output: When the main shaft is in a self-sustaining rotation state, its torque is transmitted to the generator rotor through the coupling; the stator is fitted with the first insertion part of the pressure shell through the second insertion part (fitting gap 0.005~0.01mm, coaxiality error ≤0.02mm), which restricts the relative position of the stator and the pressure shell, ensuring that the rotor axis coincides with the main shaft axis, and avoiding the rubbing fault caused by uneven air gap between the generator rotor and stator; the rotor rotates in the inner cavity of the stator and cuts the magnetic field lines to generate induced electromotive force, which is rectified and stabilized by the controller before outputting electrical energy.

[0068] S6. Adaptive Adjustment under Operating Conditions: After the main shaft enters a self-sustaining rotation state, the main shaft speed, shaft vibration amplitude, and combustion chamber outlet gas temperature are monitored in real time (monitoring sampling frequency 1kHz to ensure real-time response). When it is determined based on the above monitoring parameters that the preload of the angular contact ball bearings decreases due to thermal expansion or aerodynamic load (judgment logic: speed increases by 10% + vibration amplitude increases by 20% + combustion temperature increases by 50℃, and compensation is triggered if all three conditions are met simultaneously), the wave spring B with a larger initial compression releases its preload reserve through its own deformation to offset the preload loss and maintain the positive preload state of the angular contact ball bearings A and B. When switching to different calorific value power generation fuels (suitable for natural gas, hydrogen, diesel, methanol, etc., with a calorific value range of 20-50MJ / kg), the pressure pulsation amplitude in the combustion chamber increases. The vortex end elastic ring and the pressure end elastic ring absorb the pulsation energy through controllable elastic deformation, suppressing the shaft vibration amplitude and ensuring operational stability under multi-fuel conditions.

[0069] S7. Shutdown Process Control: After receiving a shutdown command, the controller cuts off the fuel supply to the fuel inlet, causing the combustion chamber to shut down and the turbine to lose its driving power. Once the temperature at the gas outlet drops to a preset shutdown threshold (threshold 100-200℃, to confirm complete combustion and avoid residual fuel explosion) and the spindle speed drops to a preset coasting threshold (threshold 500-1000rpm, to avoid high-speed braking damage to the shaft system), the controller switches the generator back to motor mode and applies a reverse braking current to the stator winding (braking current 1.2-1.5 times the rated current, braking time ≤10s), smoothly dragging the spindle speed to zero speed through energy consumption braking. After confirming that the spindle has completely stopped, the process ends.

Claims

1. A high power density micro gas turbine generator, characterized by: This includes a turbocharger, combustion chamber, generator, coupling, and heat exchanger; A turbocharger consists of a core, a pressure housing assembly, and a turbine housing assembly. The core unit includes a main shaft, a turbine, bearing inner ring components, an impeller, a support housing assembly, bearing outer ring components, and a shaft vibration damping assembly. The main shaft has a vortex end and a pressure end at its two ends. From the pressure end to the vortex end, the main shaft has an impeller mounting section, an intermediate section, and a turbine connecting section with progressively increasing shaft diameters. An annular stepped surface A is provided between the intermediate section and the turbine connecting section. The turbine is fixed to the end face of the turbine connecting section of the main shaft. The bearing inner ring components are fitted onto the intermediate section of the main shaft. The impeller is mounted on the impeller mounting section of the main shaft. The support housing assembly includes a bearing body; the end face of the bearing body facing the impeller is the pressure end end face, and the end face of the bearing body facing the turbine is the vortex end end face. The bearing outer ring components include a bearing outer ring A, a bearing outer ring B, and a wave spring for providing preload. The shaft vibration damping assembly includes a vortex end elastic ring and a pressure end elastic ring. The vortex end elastic ring is installed between the bearing outer ring A and the bearing body; the pressure end elastic ring is installed between the bearing outer ring B and the bearing body. The pressure housing assembly includes a pressure housing and a blade diffuser; the pressure housing has a cavity X inside for accommodating the impeller, and a first fixed part and a second fixed part arranged opposite to each other on the outside of the pressure housing, as well as an air inlet B and an air outlet B for air to enter and exit; the pressure housing also has a first insertion part arranged concentrically with the first fixed part; the pressure housing is fixedly connected to the pressure end face of the bearing body through the second fixed part; the air inlet B of the pressure housing is in communication with the atmosphere; the blade diffuser is installed inside the cavity X and is arranged around the circumferential outer side of the impeller for diffuser and pressurize the high-speed airflow thrown out by the impeller; The volute assembly includes a volute and a turbine guide; the volute has an internal cavity Y for accommodating the turbine, an external third fixed connection, an exhaust outlet A for discharging exhaust gas, and a gas inlet for entering the combustion gas; the volute is fixedly connected to the volute end face of the bearing housing through the third fixed connection; the turbine guide is installed in the cavity Y and located upstream of the turbine along the direction of combustion gas flow. The combustion chamber is equipped with a premixing chamber and a combustion chamber that are interconnected. The bottom of the combustion chamber is equipped with a fuel inlet that connects to the premixing chamber. The side wall of the combustion chamber is equipped with an air inlet A that connects to the premixing chamber. The top of the combustion chamber is equipped with a gas outlet that connects to the combustion chamber. An igniter is fixedly installed on the outer side wall of the combustion chamber. The gas outlet of the combustion chamber is connected to the gas inlet of the volute. The generator includes a stator and a rotor; the rotor is rotatably installed in the inner cavity of the stator; a second plug-in part and a fifth fixed part are provided on one end face of the stator; the stator is plugged into the first plug-in part of the pressure shell through the second plug-in part with a clearance fit; the stator is fixedly connected to the first fixed part of the pressure shell through the fifth fixed part. One end of the coupling is connected to the main shaft impeller mounting section, and the other end is connected to the generator rotor, thereby transmitting the torque of the main shaft to the rotor; The heat exchanger has internally separate tube cavities and shell cavities. Externally, the heat exchanger has an air inlet C and an air outlet C connected to the tube cavities, and an exhaust gas inlet B and an exhaust gas outlet B connected to the shell cavity. The air outlet C of the heat exchanger is connected to the air inlet A of the combustion chamber. The air inlet C of the heat exchanger is connected to the air outlet B of the pressure shell. The exhaust gas inlet of the heat exchanger is connected to the exhaust gas outlet A of the volute. The exhaust gas outlet B of the heat exchanger is connected to the atmosphere.

2. The high power density micro gas turbine generator as described in claim 1, characterized in that: The bearing inner ring related components include a pressure end sealing bushing, an angular contact ball bearing B, an inter-bearing bushing, and an angular contact ball bearing A, which are arranged sequentially from the pressure end to the volute end of the main shaft; the inner rings of the angular contact ball bearing A and the angular contact ball bearing B are respectively fixed relative to the middle section of the main shaft; The impeller is mounted on the impeller mounting section of the main shaft. Its end face near the pressure end is positioned, and its end face near the vortex end abuts against the pressure end sealing sleeve, thereby causing the pressure end sealing sleeve-angular contact ball bearing B-bearing sleeve-angular contact ball bearing A to be tightly pressed against the annular step surface A of the main shaft in sequence. The supporting housing assembly also includes a volute end cap and a pressure end cap; the bearing body has an internal mounting channel that runs through both ends of the bearing body, and the mounting channel has a wave spring abutment surface A and a wave spring abutment surface B. The mounting channel accommodates the bearing inner ring related components and the bearing outer ring related components; the inner hole seal of the volute end cap is rotatably mounted on the spindle turbine connecting section and is fixedly connected to the volute end face of the bearing body; the inner hole seal of the pressure end cap is rotatably mounted on the pressure end sealing bushing and is fixedly connected to the pressure end face of the bearing body. The wave springs in the bearing outer ring assembly include wave spring A and wave spring B; bearing outer ring A is locked integrally with the scroll end cap, and bearing outer ring B is locked integrally with the pressure end cap; bearing outer ring A is fixedly fitted onto the outer ring of angular contact ball bearing A and abuts against the end face of the outer ring of angular contact ball bearing A; bearing outer ring B is fixedly fitted onto the outer ring of angular contact ball bearing B and abuts against the end face of the outer ring of angular contact ball bearing B; both wave spring A and wave spring B are fitted onto the bearing bushing; wave spring A is compressed and positioned between the wave spring abutting surface A and the end face of bearing outer ring A, providing preload force for angular contact ball bearing A; wave spring B is compressed and positioned between the wave spring abutting surface B and the end face of bearing outer ring B, providing preload force for angular contact ball bearing B; The vortex end elastic ring in the shaft vibration damping assembly is installed between the outer circular surface of the bearing outer ring A and the inner wall of the mounting channel, and is positioned circumferentially and axially, and is relatively fixed to the inner wall of the mounting channel; the pressure end elastic ring in the shaft vibration damping assembly is installed between the outer circular surface of the bearing outer ring B and the inner wall of the mounting channel, and is positioned axially and circumferentially, and is relatively fixed to the inner wall of the mounting channel.

3. The high power density micro gas turbine generator as described in claim 2, characterized in that: A spline sleeve is fixedly connected to the end face of the main shaft impeller mounting section by a shaft locking screw. The outer circular surface of the spline sleeve is provided with an impeller positioning surface. The spline sleeve is provided with stepped bolt holes that pass through both ends of its interior. The stepped bolt holes include a first hole section relatively far from the main shaft and a second hole section relatively close to the main shaft. The first hole section is provided with an internal spline A for power output. The end face of the main shaft impeller mounting section is provided with an internal thread hole corresponding to the stepped bolt hole. The shaft locking screw passes through the stepped bolt hole and is screwed into the internal thread hole, thereby fixing the spline sleeve axially. Then, the spline sleeve sequentially presses the impeller, pressure end sealing sleeve, angular contact ball bearing B, bearing inter-sleeve sleeve, and angular contact ball bearing A onto the annular step surface A of the main shaft. At the same time, the bearing outer ring A and bearing outer ring B maintain the preload of the wave spring A and wave spring B, respectively. The rotor is provided with an internal spline B, and the center line of the internal spline B coincides with the center line of the rotor shaft. The coupling has external splines with drum-shaped teeth at both ends. The coupling is connected to the internal spline A of the spline sleeve and the internal spline B of the rotor through the external splines with drum-shaped teeth at both ends.

4. The high power density micro gas turbine generator as described in claim 3, characterized in that: The structures of the vortex end elastic ring and the pressure end elastic ring are completely identical; both are made of spring steel and are integrally formed circular ring components; both include a circular ring body, with multiple outer arc protrusions evenly distributed in a ring on the outer circumferential surface of the circular ring body, and multiple inner arc protrusions evenly distributed in a ring on the inner wall of the circular ring body. The length directions of the outer and inner arc protrusions are parallel to the axial direction of the circular ring body; all outer arc protrusions and all inner arc protrusions are staggered; the convex arc surface between the two sides of the length direction of the outer arc protrusion is defined as the outer working surface, and the concave arc surface between the two sides of the length direction of the inner arc protrusion is defined as the inner working surface; all outer working surfaces share an annular surface A, and all inner working surfaces share an annular surface B. Annular surface A, annular surface B, the outer circumferential surface of the circular ring body, and the inner wall of the circular ring body are coaxial; after the circular ring body is assembled, all outer working surfaces simultaneously make tight contact with the inner wall of the bearing housing mounting channel, and all inner working surfaces simultaneously form a clearance fit with the outer circumferential surface of the bearing outer ring A or the outer circumferential surface of the bearing outer ring B.

5. The high power density micro gas turbine generator as described in claim 4, characterized in that: The ring body is provided with a pin hole A; correspondingly, the bearing outer ring A or bearing outer ring B is provided with a pin hole X corresponding to the position of pin hole A; after the ring body is assembled, the ring body and bearing outer ring A are locked together by passing a locking pin through pin hole A and pin hole X, or the ring body and bearing outer ring B are locked together, thereby restricting the circumferential movement of the ring body. The number of outer arc protrusions and inner arc protrusions are 4-8 each, and the number of outer arc protrusions is the same as the number of inner arc protrusions; the outer working surface of the outer arc protrusion occupies the central angle α, and the inner working surface of the inner arc protrusion occupies the central angle β. The value range of central angle α is 5-15°, and the value range of central angle β is 5-15°. The interval central angle γ between any adjacent central angle α and central angle β is the same. Within the complete circumference angle of the annular body, all central angle α and all central angle β do not overlap, so that central angle α and central angle β are alternately arranged within a complete circumference angle. Both sides of the outer arc protrusion along its length direction are smoothly transitioned to the outer circular surface of the ring body through an arc ramp A, and both sides of the inner arc protrusion along its length direction are smoothly transitioned to the inner wall of the ring body through an arc ramp B; both ends of the outer arc protrusion along its length direction are provided with an outer chamfered surface for a smooth transition between the end face of the ring body and the end face of the ring body, and both ends of the inner arc protrusion along its length direction are provided with an inner chamfered surface for a smooth transition between the end face of the ring body and the end face of the ring body. The thickness S1 of the ring body is defined as the difference between the outer radius of the ring body and the inner radius of the ring body, with a value range of 1-1.5mm; the thickness S2 of the outer arc protrusion is defined as the difference between the radius of the annular surface A and the outer radius of the ring body, with a value range of 0.13-0.2 times S1; the thickness S3 of the inner arc protrusion is defined as the difference between the radius of the inner hole of the ring body and the radius of the annular surface B, with a value range of 0.13-0.2 times S1.

6. The high power density micro gas turbine generator as described in claim 5, characterized in that: The section corresponding to the bushing between the spindle and the bearing is provided with an assembly process section. This assembly process section includes a reduced diameter section and tapered transition sections at both ends of the reduced diameter section. The two tapered transition sections are used to smoothly connect the reduced diameter section with the standard outer diameter section of the middle section. The initial assembly compression of wave spring B is greater than that of wave spring A, so that both angular contact ball bearing A and angular contact ball bearing B can maintain a controlled positive preload. The inner holes of bearing outer ring A and bearing outer ring B are respectively provided with outer ring positioning surface A and outer ring positioning surface B; bearing outer ring A abuts against the outer ring end face of angular contact ball bearing A through outer ring positioning surface A; bearing outer ring B abuts against the outer ring end face of angular contact ball bearing B through outer ring positioning surface B.

7. A method for generating electricity from a high-power-density micro gas turbine, applied to the high-power-density micro gas turbine generator described in claim 6, characterized in that the steps include... as follows: S1. Start-up and start-up in one: The generator's working state is switched by the controller corresponding to the generator, and the generator's start-up and start-up characteristics are called to make it run in motor mode: The controller inverts DC power into AC power and inputs it into the stator windings to drive the rotor to output torque, which drives the main shaft to rotate through the coupling, dragging the turbocharger to the preset ignition and combustion speed threshold. During this process, the following two things happen simultaneously: Ⅰ. The impeller in the compression chamber X rotates synchronously with the main shaft, drawing in filtered outside air from the air inlet B and compressing it through the impeller to generate compressed air for initial combustion. The compressed air enters the premixing chamber through the air inlet A. II. Supply ignition fuel and power to the igniter; Based on the above synchronization, the igniter generates ignition energy to ignite the gas mixture in the premix chamber, thereby establishing initial combustion; S2. Combustion mode switching: After detecting that the temperature at the gas outlet reaches the preset switching threshold, the initial combustion is determined to be stable; then, power generation fuel is continuously supplied to the fuel inlet, and the supply of ignition fuel is maintained to keep the flame stable; the power generation fuel is mixed with the compressed air in the premixing chamber and burned in the combustion chamber to generate working gas for driving the turbine; the power generation fuel supply is gradually increased, and the turbine is driven by the generated working gas, so that the main shaft speed is gradually increased; after the power generation fuel combustion is stable, the ignition fuel supply is cut off; when the main shaft speed reaches the preset self-sustaining combustion speed threshold, the controller switches the generator to power generation mode; S3. Turbine vibration control: The working gas is discharged from the gas outlet of the combustion chamber, enters the cavity Y of the volute through the gas inlet, and is rectified by the turbine guide to impact the turbine blades, driving the main shaft into a self-sustaining rotation state. The exhaust gas after doing work is discharged from the exhaust gas outlet A of the volute, and then enters the shell cavity of the heat exchanger through the exhaust gas inlet to provide a heat source for subsequent heat recovery. During spindle operation, the back-to-back arrangement of angular contact ball bearings A and B restricts spindle axis drift. Wave springs A and B apply preload to angular contact ball bearings A and B respectively to suppress axial movement of the spindle and eliminate internal clearance of angular contact ball bearings A and B. When the spindle vibrates due to unbalanced centrifugal force or airflow pulsation, the volute end elastic ring and the pressure end elastic ring undergo controllable elastic deformation to absorb vibration energy and reduce shaft bending stiffness. This adjusts the critical speed of the spindle to outside the operating speed range, eliminating the risk of resonance of the spindle in the entire operating speed range. S4. Compressed air heat recovery: When the main shaft rotates, it drives the impeller to rotate synchronously. The filtered air is drawn into the pressure chamber X through the air inlet B. After being compressed by the impeller and pressurized by the blade intensifier, compressed air is formed. Compressed air is discharged from air outlet B and then enters the tube cavity of the heat exchanger through air inlet C. It exchanges heat with the exhaust gas from the volute exhaust gas outlet A in the heat exchanger shell cavity. After absorbing heat and heating up, it is discharged through air outlet C and enters the premixing chamber through air inlet A of the combustion chamber to participate in fuel blending. S5. Coaxial power output: When the main shaft is in a self-sustaining rotation state, its torque is transmitted to the generator rotor through the coupling; the stator is fitted with the first insertion part of the pressure shell through the second insertion part, which restricts the relative position of the stator and the pressure shell, ensuring that the rotor axis coincides with the main shaft axis, and avoiding the rubbing failure caused by uneven air gap between the generator rotor and stator; the rotor rotates in the stator cavity and cuts the magnetic field lines to generate an induced electromotive force, which is rectified and regulated by the controller before outputting electrical energy; S6. Adaptive Adjustment of Operating Conditions: After the main shaft enters the self-sustaining rotation state, the supply of fuel for power generation is gradually increased, causing the main shaft speed to gradually increase to the rated power generation condition. During this process, the main shaft speed, shaft vibration amplitude, and combustion chamber outlet gas temperature are monitored in real time. When it is determined based on the above monitoring parameters that the preload of the angular contact ball bearings decreases due to thermal expansion or aerodynamic load, the wave spring B with a larger initial compression releases the preload reserve through its own deformation to offset the preload loss and maintain the positive preload state of the angular contact ball bearings A and B. When switching to power generation fuels with different calorific values, the pressure pulsation amplitude in the combustion chamber increases. The vortex end elastic ring and the pressure end elastic ring absorb the pulsation energy through controllable elastic deformation, suppressing the shaft vibration amplitude and ensuring the operational stability under multi-fuel conditions.

8. The high power density micro gas turbine power generation method as described in claim 7, characterized in that, The method also includes step S7, which follows step S6. S7. Shutdown process control: After receiving the shutdown command, the controller cuts off the fuel supply to the fuel inlet, causing the combustion chamber to shut down and the turbine to lose its driving power. After the temperature at the gas outlet drops to the preset shutdown threshold and the spindle speed drops to the preset coasting threshold, the controller switches the generator back to motor mode and applies a reverse braking current to the stator winding to smoothly drag the spindle speed to zero through energy consumption braking. The process ends once the spindle has completely stopped rotating.

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