Effect of Cooling on the Aerodynamic Performance in the Intercooled Compressor Vanes

2017 ◽  
Author(s):  
Long-gang Liu ◽  
Xue-song Li ◽  
Xiao-dong Ren ◽  
Chun-wei Gu
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Curve Surface ◽  
Aerodynamic Performance ◽  
Cooling Effect ◽  
Main Stream ◽  
Two Dimensional ◽  
Convective Cooling ◽  
Cooling Channels ◽  
Turbulent Separation

An intercooling technique using convective cooling channels in the compressor stator vanes has been proposed in recent years. In this paper, two cooling methods are presented and conjugate heat transfer method is used in the numerical simulation to study the effect of cooling on the laminar boundary layer and turbulent boundary layer in compressors. The overall performance of the compressor is also analyzed. A flat plate in T3C series experiments under adverse pressure gradient has been simulated to verify the aerodynamic simulation and preliminarily investigate the cooling effect. Subsequently, a two-dimensional compressor vane NACA65-(12A2I8b)10 has been numerically simulated to study the cooling effect on two-dimensional boundary layer of the curve surface. The numerical simulation results of the vane without cooling channel are in good agreement with the experiment data by NASA. By comparing it with the case which has convective cooling channels, it can be found that the cooling decreases the size of laminar separation bubble and delays the turbulent separation, which reduces the loss at both the design and off-design angle of attack. A three-dimensional highly-loaded five-stage axial compressor whose stator vanes have cooling channels and cooling endwalls has also been numerically simulated. The cooling channels and endwalls decrease the temperature rising of the main stream with a slight increase of the pressure rising, which indicates that this intercooling method can be used in the intercooled and recuperated (ICR) cycle. Cooling channels decrease the temperature of the stator vanes and protect them from the high temperature. Besides, the effect of cooling on the turbulent separation in the corner region has also been investigated. The cooling channels decrease the total pressure loss, which indicates that cooling has a beneficial effect on the aerodynamic performance of the compressor.

Conjugate Heat Transfer Simulation of the Intercooled Compressor Vanes Based on Discontinuous Galerkin Method

2016 ◽  
Author(s):  
Long-gang Liu ◽  
Chun-wei Gu ◽  
Xiao-dong Ren
Keyword(s):  
Heat Transfer ◽  
Discontinuous Galerkin ◽  
Gas Turbines ◽  
Conjugate Heat Transfer ◽  
Main Stream ◽  
Two Dimensional ◽  
Convective Cooling ◽  
Cooling Channels ◽  
Transfer Method ◽  
Aero Engines

Convective cooling channels are applied in a two-dimensional compressor vane to use the intercooling method to improve the efficiency of Brayton cycle and reduce the temperature of the vane. In this paper, we analyze the effect of coolant to the aerodynamic performance and heat transfer performance of the main stream and the vane. For the case of a two-dimensional compressor vane NACA65-(12A2I8b)10, the vane which has five convective cooling channels has been numerically simulated in different test conditions by discontinuous Galerkin (DG) method. The coolant is supercritical carbon dioxide whose pressure is 10MPa. Conjugate heat transfer method has been used in this paper. The numerical simulation result is similar to the experiment data and has been compared with the result of the vane without cooling channels to prove the effect of cooling channels. Cooling channels have large effect on the distribution of temperature and heat transfer coefficient. In addition, the relationship between Nu and Re on the fluid-solid interface has been analyzed and a suitable empirical equation has been obtained. This work analyzes the effect of intercooling system in the compressor and give several advice on future engineering applications in aero engines and gas turbines.

A Note on the Causes of Thin Aerofoil Stall

1959 ◽  
Vol 63 (588) ◽  
pp. 724-730 ◽  
Author(s):  
T. W. F. Moore
Keyword(s):  
Boundary Layer ◽  
Reynolds Number ◽  
Reverse Flow ◽  
Leading Edge ◽  
Two Dimensional ◽  
Separation Theory ◽  
Turbulent Separation

Recent Researches have led to some possible explanations for thin aerofoil stalling behaviour. Apart from the Owen Klanfer criterion these are the reverse flow breakdown hypothesis of McGregor and Wallis's turbulent separation theory.This note describes simple theoretical boundary layer calculations which indicate the feasibility of Wallis's hypothesis. In addition the results of some experiments on a thin two-dimensional aerofoil with various leading edge configurations with Reynolds number, based on model chord, of 1.8 million and 1 million support either of these hypotheses, depending on the leading edge configuration. It is concluded that thin aerofoil stall can occur broadly, through either of the suggested mechanisms, depending on conditions in the nose region.

Heat transfer in a periodic boundary layer near a two-dimensional stagnation point

1972 ◽  
Vol 56 (4) ◽  
pp. 619-627 ◽  
Author(s):  
Hiroshi Ishigaki
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Temperature Field ◽  
Velocity Field ◽  
Stagnation Point ◽  
High Frequency ◽  
High Frequency Oscillation ◽  
Main Stream ◽  
Two Dimensional ◽  
Mean Temperature

Following the previous velocity-field study (Ishigaki 1970), this paper studies how the temperature field in the laminar boundary layer near a two-dimensional stagnation point responds to the main-stream oscillation. The time-mean temperature field is of particular interest and is studied in detail. The velocity field is treated as known and is taken from the previous paper. In § 3 the solutions over the whole frequency range are obtained under the assumption of small amplitude oscillation and the results are compared with the existing approximate solutions for low and high frequency in terms of heat transfer. Time-mean heat transfer decreases at low frequency, but slightly increases at high frequency. Two factors that cause time-mean modification of the temperature field are examined quantitatively. In § 4 the finite amplitude case is treated under the assumption of high-frequency oscillation and a few examples of the time-mean temperature profile are shown.

Study on the Downburst Field Characteristics under the Influence of Two-Dimensional Continuous Mountains at Different Distance

2014 ◽  
Vol 580-583 ◽  
pp. 3111-3114
Author(s):  
Yi Sun ◽  
Yuan Ze Wu ◽  
Hai Tao Shi ◽  
Bai Feng Ji
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Wind Field ◽  
Strong Wind ◽  
Two Dimensional ◽  
Field Characteristic ◽  
Main Factors ◽  
Cfd Numerical Simulation ◽  
The Impact

Downburst is an outburst strong wind on or near the ground, and its wind field characteristics are significantly different from boundary layer winds. Continuous mountains at different distance are one of the main factors for the influence of downburst wind field characteristic. In this thesis, the changes of the wind field characteristics under the influence of continuous mountains at different distance after the downburst happened are studied by CFD numerical simulation. The impact of downburst is analysed and summarized through the charts.

Horizontal Axis Wind Turbine Numerical Simulation of Two Dimensional Angle of Attack

2012 ◽  
Vol 619 ◽  
pp. 111-114
Author(s):  
Jing Mei Yu ◽  
Yan Hong Yu ◽  
Pan Pan Liu
Keyword(s):  
Numerical Simulation ◽  
Wind Turbine ◽  
Hot Spot ◽  
The United States ◽  
Aerodynamic Performance ◽  
Horizontal Axis ◽  
Energy Utilization ◽  
Two Dimensional ◽  
Horizontal Axis Wind Turbine ◽  
Wind Turbine Airfoil

wind power is the most effective form of wind energy utilization, modern large-scale wind turbine with horizontal axis wind mainly. Horizontal axis wind turbine aerodynamic performance calculation of the wind turbine aerodynamics research hot spot, is a wind turbine aerodynamic optimization design and calculation of critical load. Horizontal axis wind turbine airfoil aerodynamic performance of the wind turbine operation characteristics and life plays a decisive role". Using Fluent software on the horizontal axis wind turbine numerical simulation, analysis of the United States of America S809NREL airfoil aerodynamic characteristics of different angles of attack numerical simulation, analyzes the different angles of attack in the vicinity of the pressure, velocity distribution. By solving the two-dimensional unsteady, compressible N-S equations for the calculation of wind turbine airfoil S809used the characteristics of flow around. N-S equation in body-fitted coordinate system is given, with the Poisson equation method to generate the C grid.

scholarly journals On the two-dimensional steady flow of a viscous fluid behind a solid body.―I

1933 ◽  
Vol 142 (847) ◽  
pp. 545-562 ◽  
Keyword(s):  
Boundary Layer ◽  
Viscous Fluid ◽  
Velocity Distribution ◽  
Asymptotic Approximation ◽  
Constant Velocity ◽  
Boundary Layer Theory ◽  
The Other ◽  
Main Stream ◽  
Two Dimensional ◽  
Prandtl Equations

1.1. The purpose of this paper is to exhibit, for reasons given below, calculations of the velocity distribution some distance downstream behind any symmetrical obstacle in a stream of viscous fluid, but particularly behind an infinitely thin plate parallel to the stream, the motion being two-dimensional. For a slightly viscous fluid, Blasius worked out the velocity distribution in the boundary layer from the front to the downstream end of the plate; and in a previous paper, I calculated the velocity in the wake for a distance varying from 0.3645 to 0.5 of the length of the plate from its downstream end (according to distance from its plane). In these calculations the fluid was supposed unlimited, and the undisturbed velocity in front of the plate was taken as constant. The viscosity being assumed small, the work was carried out on the basis of Pranstl's boundary layer theory, with zero pressure gradient in the direction of the stream. The velocity is then constant everywhere expect within a thin layer near the plate, and in a wake which must gradually broaden out downstream. (The broadening of the wake just behind the plate is so gradual that it could not be shown by calculations of the accuracy obtained in I). Pressure variations in a direction at right angles to the stream are negligible, and so is the velocity in that direction. Later, Tollmien attcked the problem from the other end, and found a first asymptotic approximation for the velocity distribution in the wake at a considerable distance downstream. He simplified the Prandtl equations by assuming that the departure from the constant velocity, U 0 , of the main stream is small, and neglecting terms quadratic in this departure. In other words, he applied the notion of the Oseen approximation to the Prandtl equations. His result for the velocity is U = U 0 {1 - a X -½ exp (-U 0 Y 2 /4νX)}.

scholarly journals Streakline Flow Visualization Study of a Horseshoe Vortex in a Large-Scale, Two-Dimensional Turbine Stator Cascade

1980 ◽  
Author(s):  
R. E. Gaugler ◽  
L. M. Russell
Keyword(s):  
Boundary Layer ◽  
Large Scale ◽  
Leading Edge ◽  
Horseshoe Vortex ◽  
Main Stream ◽  
Two Dimensional ◽  
Vortex System ◽  
Turbine Stator ◽  
Neutrally Buoyant ◽  
Limiting Streamlines

Neutrally buoyant helium-filled bubbles were observed as they followed the streamlines in a horseshoe vortex system around the vane leading edge in a large-scale, two-dimensional, turbine stator cascade. Inlet Reynolds number, based on true chord, ranged between 1.0 × 10 ⅝ to 3.0 × 10 ⅝. Bubbles were introduced into the endwall boundary layer through a slot upstream of the vane leading edge. The paths of the bubbles were recorded photographically as streaklines on 16-mm movie film. Individual frames from the film have been selected, and overlayed to show the details of the horseshoe vortex around the leading edge, the transport of the vortex across the passage near the leading edge is clearly seen when compared to the streaks formed by bubbles carried in the main stream. Limiting streamlines on the endwall surface were traced by the flow of oil drops.

Thermal Radiative Cooling Enabled Freeze Tweezer for Manipulating Micro Scale Objects

2011 ◽  
Author(s):  
Yang Yang ◽  
Jing Liu
Keyword(s):  
Numerical Simulation ◽  
Small Volume ◽  
Freezing Behavior ◽  
Cooling Effect ◽  
Radiative Cooling ◽  
Convective Cooling ◽  
Micro Scale

A freeze tweezer is a new kind of manipulation tool which employs the freezing force of a small volume of nucleotide ice for operating the micro-objects in an aqueous state. Previously, such typical device prototypes were respectively realized based on conductive and convective cooling effect. Aiming to present an alternative feasible way for realizing the freeze tweezer in micro or even much smaller size by thermal radiative cooling, a complete 3-D numerical simulation on the operation behaviors of such kind freeze tweezer have been implemented. As a result, the droplet freezing behavior is directly caused by the freeze tweezer rather than the thermal radiative cooling from the sidewall. It indicates that this new freeze tweezer would also complete all the functions as its previous type would achieve.

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