Modeling of Turbine Blade Tip Contact

1976 ◽  
Vol 98 (4) ◽  
pp. 435-440
Author(s):  
R. A. Burton ◽  
S. R. Kilaparti ◽  
S. R. Heckmann
Keyword(s):  
Mathematical Model ◽  
Thermal Expansion ◽  
Contact Pressure ◽  
Turbine Blade ◽  
Relative Displacement ◽  
Operating Conditions ◽  
Dynamic Displacement ◽  
Contact Patch ◽  
Full Contact ◽  
Blade Tip

A mathematical model is developed for the condition where turbine blade/shroud contact occurs at discrete patches on the shroud. The contact patch is treated as having uniform time-mean contact pressure; and several components of relative displacement are identified, these having to sum to zero in the contact patch to assure an unbroken interface in the patch. Operating conditions which meet this requirement permit the postulated patchlike contact to exist. Operating conditions which do not meet it will not be associated with such patches. The components of relative displacement are almost independent of one another and are treated as linearly additive. These are: (1) thermal expansion of the shroud material in the patch, (2) elastic indentation of the shroud by the blade tip, (3) wear of the shroud material, (4) wear of the blade tip, (5) dynamic displacement of the blade tip, (6) dynamic displacement of the shroud, (7) elastic compression of the thinned blade tip portion. Using these components and applying the foregoing condition for full contact, the speed at which the contact patch traverses along the shroud surface is solved for, and the factors which determine the width of the contact patch are determined.

scholarly journals Measurements of Strain on 310 mm Torque Converter Turbine Blades

2004 ◽  
Vol 10 (1) ◽  
pp. 55-63
Author(s):  
P. O. Sweger ◽  
C. L. Anderson ◽  
J. R. Blough
Keyword(s):  
Turbine Blade ◽  
Turbine Blades ◽  
Torque Converter ◽  
Operating Conditions ◽  
Surface Strain ◽  
Speed Ratio ◽  
Constant Input ◽  
Wide Range ◽  
Blade Tip ◽  
Input Torque

An automotive torque converter was tested in order to determine the effect of converter operating condition and turbine blade design on turbine blade strain in the region of the inlet core tab restraint. The converter was operated over a wide range of speed ratios (0 to 0.95) at constant input torque and a stall condition for two input torques. Foil-type strain gages in combination with wireless microwave telemetry were used to measure surface strain on the turbine blade. Strain measurements were made on two turbine blade designs.The steady component of strain over the range of speed ratios suggests the effect of both torque loading and centrifugal loading on the turbine blade tip. The unsteady strain was greatest at stall condition and diminished as speed ratio increased. Greater input torque at stall condition resulted in both greater steady strain and greater unsteady strain. The spectral distribution of strain over the range of tested speed ratios displayed an increase in low-frequency broadband fluctuations near stall condition. A blade-periodic event is observed which correlates to the pump-blade passing frequency relative to the turbine rotating frame. Reducing the blade-tip surface area and increasing the inlet-tab root radius reduced the range of steady strain and magnitude of unsteady strain imposed near the inlet core tab restraint over the range of operating conditions.

scholarly journals Investigation of operational characteristics of axial displacement guides for thermal expansion systems of steam turbines

2021 ◽  
Vol 23 (4) ◽  
pp. 105-119
Author(s):  
A. Yu. Sosnovskiy ◽  
B. E. Murmanskiy ◽  
Yu. M. Brodov
Keyword(s):  
Thermal Expansion ◽  
Comparative Analysis ◽  
Steam Turbine ◽  
Operating Conditions ◽  
Steam Turbines ◽  
Plastic Deformations ◽  
Traditional Design ◽  
Full Contact ◽  
Operational Characteristics ◽  
Operating Instructions

ТНЕ PURPOSE. To carry out a comparative analysis of the performance characteristics of the longitudinal movement guides of the external bearing housings of steam turbines, using the principle of rotation to ensure full contact of their lateral surfaces with the lateral surfaces of the guide groove at the base of the external bearing housing of the steam turbine. Compare the manufacturability of elements and their implementation for both existing and newly developed steam turbines .METHODS. The permissible transverse forces are determined from the strength conditions and compared for the traditional design of fixed longitudinal guides and the design of guides, in which the principle of rotation is used to avoid "biting" of the bearing housing on the guides when temperature misalignment appears along the flanges of the turbine cylinder. Also, the allowable forces are determined and compared from the condition of the absence of plastic deformations in any of the elements of the interface of the guides, the base frame and the bearing housing. Based on the results obtained, the value of the permissible temperature misalignment along the flanges of the turbine cylinder is estimated. The analysis was carried out in relation to the operating conditions of the front bearing housing and HPC of turbines of the T 100/120-130 UTZ family.RESULTS. It has been established that all the considered designs of guides with pivoting elements make it possible to exclude the occurrence of plastic deformations in the junction of the base frame and the outboard bearing housing at a temperature misalignment of 20°C regulated in most turbine operating instructions. CONCLUSION. The design of longitudinal keys proposed by UTZ does not require a change in the technology for manufacturing the foundation frames and allows the unit to be modernized during repairs in a CHP. The best performance disc guide design can be used in new turbine designs or factory retrofits.

The Validation of Flutter Prediction in a Linear Cascade of Non-Rigid Turbine Blades

2018 ◽  
Author(s):  
Vaclav Slama ◽  
Bartolomej Rudas ◽  
Jiri Ira ◽  
Ales Macalka ◽  
Petr Eret ◽  
...  
Keyword(s):  
Turbine Blade ◽  
Turbine Blades ◽  
Travelling Wave ◽  
Operating Conditions ◽  
Steam Turbines ◽  
Aerodynamic Forces ◽  
Linear Cascade ◽  
Unsteady Aerodynamic ◽  
Blade Tip ◽  
Last Stage

In low-pressure steam turbines, aerodynamic and structural design of the last stage blades is critical in determining the power plant efficiency. The development of longer last stage blades which are recently over 1 meter in length is an important task for steam turbine manufactures. The design process involves a flutter analysis of last stage blade tip sections where increased unsteady aerodynamic forces and moments might endanger the blade aerodynamic stability. However, numerical design tools must be validated using measurements in test facilities under various operating conditions. In this work, ANSYS CFX is used for flutter prediction of turbine blade tip sections oscillating in a travelling wave mode. Simulations are compared to experimental results obtained from controlled flutter tests in a wind tunnel with a linear cascade of eight turbine blade profiles made of carbon fibre. Central four blades are flexibly mounted each with two degrees of freedom (i.e. bending and torsion motions). Large deflections of thin blade profiles are accounted for the estimation of unsteady aerodynamic forces and moments. A satisfactory agreement between the simulations and experiments is achieved.

Validation of mathematical model of electrothermal calculation of DC catenary on the basis of scale model

2018 ◽  
Vol 77 (4) ◽  
pp. 222-229 ◽  
Author(s):  
A. V. Paranin ◽  
A. B. Batrashov
Keyword(s):  
Mathematical Model ◽  
Operating Conditions ◽  
Scale Model ◽  
Contact Network ◽  
Scaled Model ◽  
Cross Sectional ◽  
Current Collection ◽  
Topological Features ◽  
Study Results ◽  
Real Physical Process

The article compares the results of calculation of the finite element simulation of current and temperature distribution in the scale model of the DC catenary with the data of laboratory tests. Researches were carried on various versions of the structural design of catenary model, reflecting the topological features of the wire connection, characteristic of the DC contact network. The proportions of the cross-sectional area of the scaled model wires are comparable to each other with the corresponding values for real DC catenary. The article deals with the operating conditions of the catenary model in the modes of transit and current collection. When studying the operation of the scale catenary model in the transit mode, the effect of the structural elements on the current distribution and heating of the wires was obtained. Within the framework of the scale model, theoretical assumptions about the current overload of the supporting cable near the middle anchoring have been confirmed. In the current collection mode, the experimental dependences of the current in the transverse wires of the scale model are obtained from the coordinate of the current collection point. Using the model it was experimentally confirmed that in the section of the contact wire with local wear, not only the temperature rise occurs but also the current redistribution due to the smaller cross section. Thus, the current share in other longitudinal wires of the scale model increases and their temperature rises. Scale and mathematical models are constructed with allowance for laboratory clamps and supporting elements that participate in the removal of heat from the investigated wires. Obtained study results of the scale model allow to draw a conclusion about the adequacy of the mathematical model and its correspondence to the real physical process. These conclusions indicate the possibility of applying mathematical model for calculating real catenary, taking into account the uneven contact wear wire and the armature of the contact network.

scholarly journals Comprehensive Parameters Identification and Dynamic Model Validation of Interior-Mount Line-Start Permanent Magnet Synchronous Motors

Machines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 4 ◽  
Author(s):  
Luqman S. Maraaba ◽  
Zakariya M. Al-Hamouz ◽  
Abdulaziz S. Milhem ◽  
Ssennoga Twaha
Keyword(s):  
Mathematical Model ◽  
Permanent Magnet ◽  
High Efficiency ◽  
Experimental Tests ◽  
Induction Machines ◽  
Test Methods ◽  
Operating Conditions ◽  
Test Method ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors

The application of line-start permanent magnet synchronous motors (LSPMSMs) is rapidly spreading due to their advantages of high efficiency, high operational power factor, being self-starting, rendering them as highly needed in many applications in recent years. Although there have been standard methods for the identification of parameters of synchronous and induction machines, most of them do not apply to LSPMSMs. This paper presents a study and analysis of different parameter identification methods for interior mount LSPMSM. Experimental tests have been performed in the laboratory on a 1-hp interior mount LSPMSM. The measurements have been validated by investigating the performance of the machine under different operating conditions using a developed qd0 mathematical model and an experimental setup. The dynamic and steady-state performance analyses have been performed using the determined parameters. It is found that the experimental results are close to the mathematical model results, confirming the accuracy of the studied test methods. Therefore, the output of this study will help in selecting the proper test method for LSPMSM.

scholarly journals Heat Transfer in Rotating Serpentine Passages With Trips Normal to the Flow

1992 ◽  
Vol 114 (4) ◽  
pp. 847-857 ◽  
Author(s):  
J. H. Wagner ◽  
B. V. Johnson ◽  
R. A. Graziani ◽  
F. C. Yeh
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Large Scale ◽  
Flow Direction ◽  
Operating Conditions ◽  
Transfer Model ◽  
Transfer Coefficients ◽  
Flow Equations ◽  
Turbine Blade Cooling ◽  
Heat Transfer Coefficients

Experiments were conducted to determine the effects of buoyancy and Coriolis forces on heat transfer in turbine blade internal coolant passages. The experiments were conducted with a large-scale, multipass, heat transfer model with both radially inward and outward flow. Trip strips on the leading and trailing surfaces of the radial coolant passages were used to produce the rough walls. An analysis of the governing flow equations showed that four parameters influence the heat transfer in rotating passages: coolant-to-wall temperature ratio, Rossby number, Reynolds number, and radius-to-passage hydraulic diameter ratio. The first three of these four parameters were varied over ranges that are typical of advanced gas turbine engine operating conditions. Results were correlated and compared to previous results from stationary and rotating similar models with trip strips. The heat transfer coefficients on surfaces, where the heat transfer increased with rotation and buoyancy, varied by as much as a factor of four. Maximum values of the heat transfer coefficients with high rotation were only slightly above the highest levels obtained with the smooth wall model. The heat transfer coefficients on surfaces where the heat transfer decreased with rotation, varied by as much as a factor of three due to rotation and buoyancy. It was concluded that both Coriolis and buoyancy effects must be considered in turbine blade cooling designs with trip strips and that the effects of rotation were markedly different depending upon the flow direction.

Investigation of the Thermodynamic Properties of Anharmonic Crystals with Defects and Influence of Anharmonicity in Exafs by the Moment Method

1998 ◽  
Vol 12 (02) ◽  
pp. 191-205 ◽  
Author(s):  
Vu Van Hung ◽  
Nguyen Thanh Hai
Keyword(s):  
Thermal Expansion ◽  
Thermodynamic Properties ◽  
Phase Change ◽  
Specific Heat ◽  
Thermal Expansion Coefficient ◽  
Expansion Coefficient ◽  
Moment Method ◽  
Adiabatic Compressibility ◽  
Relative Displacement ◽  
The Moment

By the moment method established previously on the basis of the statistical mechanics, the thermodynamic properties of a strongly anharmonic face-centered and body-centered cubic crystal with point defect are considered. The thermal expansion coefficient, the specific heat Cv and Cp, the isothermal and adiabatic compressibility, etc. are calculated. Our calculated results of the thermal expansion coefficient, the specific heat Cv and Cp… of W, Nb, Au and Ag metals at various temperatures agrees well with the measured values. The anharmonic effects in extended X-ray absorption fine structure (EXAFS) in the single-shell model are considered. We have obtained a new formula for anharmonic contribution to the mean square relative displacement. The anharmonicity is proportional to the temperature and enters the phase change of EXAFS. Our calculated results of Debye–Waller factor and phase change in EXAFS of Cu at various temperatures agrees well with the measured values.

Sign in / Sign up

Export Citation Format

Share Document