scholarly journals ВИБІР І ОБҐРУНТУВАННЯ МЕТОДУ ГЕНЕРАЦІЇ СІТКИ ДЛЯ МОДЕЛЮВАННЯ ТЕЧІЇ У ВЕНТИЛЯТОРІ ГАЗОТУРБІННОГО ДВИГУНА

2020 ◽  
pp. 34-40
Author(s):  
Михаил Владимирович Хижняк ◽  
Екатерина Викторовна Дорошенко ◽  
Вячеслав Юрьевич Усенко
Keyword(s):  
Finite Element ◽  
Literature Review ◽  
Numerical Experiment ◽  
Flow Function ◽  
Dynamic Flow ◽  
Axial Fan ◽  
Hybrid Mesh ◽  
Gas Dynamic ◽  
Structured Mesh ◽  
Bypass Ratio

The study of flow in aircraft gas turbine engines is one of the main components for the creation of new compressors and fans with improved aerodynamic, acoustic, strength, overall weight, and other characteristics. In modern scientific research, the methods of the physical experiment are used at the final stages of flow studies in blade machines. a numerical experiment is used in the early stages. An obvious advantage of the numerical experiment is the ability to study many variants of constructions under different input and boundary conditions in a short period. However, a numerical experiment requires a preliminary selection and justification of its parameters and components. One such important component is the type of calculation mesh. The literature review shows that it is impossible to make an unambiguous conclusion about the choice of the type of method for generating the finite element mesh and the turbulence model. This work aims to compare a hybrid and structured mesh for flow modeling in an axial fan of a bypass engine with a high bypass ratio. Two impellers of a bypass engine with a high bypass ratio are selected as the object of study. Flow simulation in fans was studied at a rotor speed of 2202 rpm in the range of values of the gas-dynamic flow function at the inlet q (λ) = 0.4 ... 0.65. Based on the literature review, the system of Navier-Stokes equations was closed by the SST turbulent model. To select and substantiate the method of finite-element grid generation, a structured and hybrid mesh for two fan variants were constructed. According to the results of the calculations, the dependence of the pressure ratio of fan π on the gas-dynamic flow function at the inlet q (λ) was constructed. According to the results of the study, it can be stated that the discrepancy of the calculations for the impellers in the axial fan of a bypass engine with a high bypass ratio with structured and hybrid meshes will be up to 2 %. When choosing the method of mesh generation, the time of calculation is also an important factor. Studies have shown that the calculation with a structured mesh took place in less time by 50 ... 70% than when using a hybrid mesh for one variant of the geometry.

scholarly journals Моделювання течії в дворядному вентиляторі турбореактивного двоконтурного двигуна

2021 ◽  
pp. 19-24
Author(s):  
Антон Валерьевич Балалаев ◽  
Екатерина Викторовна Балалаева ◽  
Юрий Юрьевич Терещенко
Keyword(s):  
Boundary Layer ◽  
Aircraft Engine ◽  
Aerodynamic Characteristics ◽  
Rate Function ◽  
Rotor Speed ◽  
Dynamic Flow ◽  
Single Row ◽  
Gas Dynamic ◽  
Bypass Ratio ◽  
Range Of Values

Modern trends in the global aircraft industry are prompting aircraft engine engineers to create and develop various methods to improve the aerodynamic characteristics of turbomachines. The urgent need to improve the efficiency of new generation engines leads to a rapid increase in the bypass ratio of engines, which requires the development of fans with large diametrical dimensions and high aerodynamic perfection. Boundary layer control in turbomachines using tandem blade rows is one of the most promising ways to improve the aerodynamic characteristics of aircraft engine fans with a high bypass ratio. The work aims to evaluate the aerodynamic characteristics of a fan with a tandem impeller for a turbofan engine. Two fan impellers were investigated: a single-row and an equivalent tandem-row (the equivalence was ensured by the equality of the structural angles of the flow inlet and outlet and the equality of the chord of the profiles). The blade row consisted of 33 blades, the tip diameter at the inlet to the impeller was 2.37 m, the hub diameter was 0.652 m. The flow was simulated in the range of axial velocity at the inlet from 80 to 200 m/s at a relative rotor speed of 0.65, 0.85, and 0.9. For the investigated tandem fan impeller, the chord of the first row was 60% of the total chord of the profile, the length of the slotted channel was 10% of the total chord. The flow was simulated using a numerical experiment. When closing the system of Navier-Stokes equations, Menter's SST turbulence model was used. The computational grid is unstructured, with an adaptation of the boundary layer. The work shows that the use of a tandem impeller will improve the aerodynamic characteristics of the fan. As a result of the study, it was found that the pressure ratio in a fan with tandem impeller increases from 0.32 to 20% for an operating mode at a relative rotor speed of n=0.65, n=0.85, and n=0.9 in the range of values of the gas-dynamic flow rate function q (λ)=0.4...1. The greatest growth is observed on the left branches of the pressure lines. The obtained data on the efficiency of a fan with a tandem impeller showed that in the range of values of the gas-dynamic flow rate function q(λ)=0.4...0.6 and q(λ)=0.76...0.98 a tandem impeller is higher than the efficiency of a fan with a single-row impeller, for values of the gas-dynamic flow function q(λ)=0.64...0.76 - the efficiency of a fan with a tandem impeller is 4% less than the efficiency of a fan with a single-row impeller.

Effect of electric-discharge plasma on gas-dynamic flow modes of a supersonic jet impinging on a barrier

2015 ◽  
Vol 60 (4) ◽  
pp. 160-163
Author(s):  
V. M. Fomin ◽  
K. A. Lomanovich ◽  
B. V. Postnikov
Keyword(s):  
Electric Discharge ◽  
Discharge Plasma ◽  
Supersonic Jet ◽  
Dynamic Flow ◽  
Gas Dynamic

scholarly journals Improving the performance of the air-cooling unit in the cooling system of a radar

2021 ◽  
Vol 2057 (1) ◽  
pp. 012004
Author(s):  
Yu A Borisov ◽  
V V Volkov-Muzilev ◽  
D A Kalashnikov ◽  
H S Khalife
Keyword(s):  
Heat Exchanger ◽  
Gas Flow ◽  
Cooling System ◽  
Experimental Studies ◽  
Air Cooling ◽  
Axial Fan ◽  
Gas Dynamic ◽  
Cooling Unit ◽  
Calculation Results ◽  
Axial Fans

Abstract The article discusses the issues of reducing the size of the cooling unit of the antenna of a radar station by improving the gas-dynamic processes occurring in the air-cooling unit. The results of the experimental studies of the gas flow in a plate-fin heat exchanger, being blown by one axial fan are presented. The feasibility of changing the number of axial fans for organizing a more uniform flow around the heat-exchange surfaces has been determined by calculation and theoretical methods. The calculation results are confirmed by experimental studies of the air flow in the segment of the heat exchanger, which is provided by a smaller fan.

Coaction Analysis on Pile-Net-Cushion-Soil

2014 ◽  
Vol 580-583 ◽  
pp. 579-584
Author(s):  
Rui Fang Wang ◽  
Ke Yu Wang
Keyword(s):  
Finite Element ◽  
Literature Review ◽  
Measured Data ◽  
Composite Foundation ◽  
Analytic Calculation ◽  
Three Dimension ◽  
Interaction Coefficients ◽  
Flexibility Matrix ◽  
Analytic Methods ◽  
Set Up

In accordance of the principles of stress continuousness and displacement coordination, the interactions model of pile and pile, pile and soil are set up;Accoring to the symmetry of the models,1/4 of the models are extracted to set up three-dimension multipile composite foundation models.The flexibility matrix of the three reinforcements are modified to build a global flexibility matrix with the consideration of cushion's compression; Interaction coefficients of the analytic calculation are lower than those of the finite element when pile lengthen is diversity.The comparison between the on-site measured data from the literature review and results of the analytic calculation shows the settlements in the analytic calculation are smaller than those in the measured data, and the model measurements are very close to the curves from the analytic calculation. All these prove that the analytic methods proposed by this research are accurate and may function as a reference to engineering.

IMPLEMENTATION OF THE LEMAITER DAMAGE MODEL IN ANSYS FINITE ELEMENT COMPLEX

2020 ◽  
pp. 30-48
Author(s):  
D.A. Kosov ◽  
◽  
D.I. Fedorenkov ◽  
A.V. Tumanov ◽  
◽  
...  
Keyword(s):  
Finite Element ◽  
Numerical Experiment ◽  
Numerical Experiments ◽  
Damage Accumulation ◽  
Cylindrical Specimen ◽  
Damage Model ◽  
Finite Element Calculation ◽  
Element Calculation ◽  
Lemaitre Damage Model ◽  
Calculation Software

In this work, the simplified Lemaitre damage model was integrated into the ANSYS finite element calculation software. The model is implemented as a dynamically linked library of custom material for 2D problems. The model was tested on a cylindrical specimen with an annular cut. The stages of damage accumulation in the numerical experiment coincide with similar numerical experiments known in the literature.

Impeller Finite Element Analysis of Extractable Explosion-Proof Contra-Rotating Axial Fan for Mine Local Ventilation FBDC

2012 ◽  
Vol 605-607 ◽  
pp. 1372-1376
Author(s):  
Qiu Dong He ◽  
Wen Qi Yu ◽  
Shu Fen Xiao
Keyword(s):  
Finite Element ◽  
Static Pressure ◽  
Three Dimensional ◽  
Low Carbon Steel ◽  
Sound Level ◽  
Low Carbon ◽  
Axial Fan ◽  
Element Analysis ◽  
Local Ventilation ◽  
Three Dimensional Finite Element

To improve the impeller safety and reliability of extractable explosion-proof contra-rotating axial fan for mine local ventilation, Extractable Fan FBDC№9.0/2×30 was taken as the research object, and an approximate three-dimensional finite element computation model was built by using ANSYS software. The stress and displacement were calculated, too. By testing, the fan works stably. The air quantity is 655-978 m3/min, total pressure, 3443-412Pa, static pressure, 3314-118Pa. And the highest static pressure efficiency is up to 70.35%, A-weight Specific Sound Level is 17.5dB. Furthermore, the intension and stiffness of the impeller meet requirements. Sample test and field using show that the computation and the model of this impeller are right. Through reasonable design, the impeller of contra-rotating axial fan with equally-thick circular arc blade profile and ordinary hot-rolling low-carbon steel blades has the intension and the stiffness which meets demands, and the air performance reaches higher level.

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