Models of steam force and torque of a rotor subjected to the leakage of tip clearance

Huang, Dawei

doi:10.1243/095765002320877847

Cited by 3 publications

(1 citation statement)

References 14 publications

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“…They used an integral method to compute the radiative heat flux distribution. A similar study was carried out by Gandjalikhan Nassab [4], but the computation was based on the two-flux radiation model. Based on energy conversion between gas enthalpy and thermal radiation, Tanigawa et al [5] proposed a new type of gas-to-gas heat exchanger equipped with a pair of circular porous metal plates.…”

Section: Introductionmentioning

confidence: 99%

Heat transfer characteristics of a cylindrical porous radiant air heater under the influence of a two-dimensional axisymmetric radiative field

Keshtkar

Nassab

Nasr

2009

Proceedings of the Institution of Mechanical Engineers, Part A:

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This work presents the heat transfer characteristics of a new type of porous radiant air heater (PRAH) that operates on the basis of an effective energy conversion method between flowing gas enthalpy and thermal radiation. In this system, four porous layers consisting of porous radiant burner (PRB), high-temperature (HT) section, first heat recovery section, and second heat recovery section are considered. These layers are separated from each other by three quartz glass walls. The PRB generates a large amount of thermal radiative energy, which is converted into gas enthalpy in heat recovery layers. In the HT section, the gas enthalpy of the exhaust flow from PRB converts into thermal radiation. At each layer, the gas and solid phases are considered in non-local thermal equilibrium and combustion in the PRB is modelled by considering a non-uniform heat generation zone. The homogeneous porous media, in addition to its convective heat exchange with the gas, may absorb, emit, and scatter thermal radiation. In order to determine the thermal characteristics of the proposed PRAH, a two-dimensional model is used to solve the governing equations for porous medium and gas flow and the discrete ordinates method is used to obtain the distribution of radiative heat flux in the porous media. Computational results show that this type of air heater has much higher efficiency than the conventional ones. In addition, it is clarified that the high optical thickness and low scattering coefficient for porous layers improve the heater efficiency. In order to validate the applied numerical method at the present analysis, the results are compared with some reported theoretical and experimental results by other investigators and good agreement is found.for this purpose. This is due to the extremely high heat transfer coefficient and large heat transfer surface area for the gas flow through porous matrix. For the first time, Echigo [1] studied the problem of recovering energy from hot exhaust gases by placing a porous layer normal to the gas flow in exhaust ducts. In that study, the solid matrix was assumed not to scatter radiant energy. His analysis revealed that a substantial amount of gas enthalpy might be recovered to radiative energy travelling upstream from the porous segment. Wang and Tien [2] extended Echigo's analysis using the two-flux radiation model and the scattering effect of the porous layer was considered in their computations. Another theoretical study on heat recovery (HR)

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Section: Introductionmentioning

confidence: 99%

Heat transfer characteristics of a cylindrical porous radiant air heater under the influence of a two-dimensional axisymmetric radiative field

Keshtkar

Nassab

Nasr

2009

Proceedings of the Institution of Mechanical Engineers, Part A:

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Research on the dynamic characteristics of rotor-bearing-seal system with breathing cracks under steam flow excited force

Cao,

Xue,

2023

International Journal of Non-Linear Mechanics

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Anisotropic Vibration Characteristics Analysis of Steam Turbine Rotor Influenced by Steam Flow Excited Force Coupling Thermal and Dynamic Loads

Xue

Cao

2023

Journal of Energy Resources Technology

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In order to reveal the influence of thermal and dynamic loads coupling on vibration characteristic of steam turbine rotor, the high pressure cylinder anisotropic rotor of a 1000MW ultra-supercritical steam turbine was modeled by the lumped parameter method. The steam flow excited force of the front 8 stages obtained through the numerical simulation before and after the coupling was converted to the equivalent gas bearing and added on the rotor, and the influence of steam flow excited force on rotor vibration characteristics was obtained by the Riccati transfer matrix method. The results show that, considering the thermal and dynamic loads, the two ends of the ellipse trajectory are smaller and the middle is larger. Before and after coupling thermal and dynamic loads, the azimuth of ellipse trajectory increases with the increase of load and nodes. The greater the load, the greater the changing range of azimuth. As the load increases, the first-order natural speed of rotor increases and the second-order natural speed decreases, but the natural speed after the coupling is noticeably lower than that before the coupling. The change scope of the first-order amplitude shrinks with the load increasing. The first-order logarithmic decrement rate can be increased under the relatively higher load by coupling thermal and dynamic loads, but the stability margin of rotor is insufficient, which causes the instability.

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Models of steam force and torque of a rotor subjected to the leakage of tip clearance

Cited by 3 publications

References 14 publications

Heat transfer characteristics of a cylindrical porous radiant air heater under the influence of a two-dimensional axisymmetric radiative field

Heat transfer characteristics of a cylindrical porous radiant air heater under the influence of a two-dimensional axisymmetric radiative field

Research on the dynamic characteristics of rotor-bearing-seal system with breathing cracks under steam flow excited force

Anisotropic Vibration Characteristics Analysis of Steam Turbine Rotor Influenced by Steam Flow Excited Force Coupling Thermal and Dynamic Loads

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