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1

Test stand for modelling of combustion processes of liquid fuels

Jankowski A.

Journal of KONES

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2014

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Vol. 21, No. 2

121--126

EN

Boundary layer is a reflection of the phenomena occurring in the combustion of liquid fuels with perpendicular to the surface of adding mass. For study the influence the thermal boundary layer on the process of combustion a special test stand has been developed, in which the flow of the medium with the addition of mass can be realized. Quartz windows and magnesium oxide powder, which is added for allow visualization of the airflow stream. Quartz windows are placed in the sidewalls of the chamber. The paper presents the test stand. The test stand consists of the following main components: test chamber, the main air preparation module, auxiliary air preparation module, module of particulate cartridge, air compressor, compensation tank, control unit and accessories in the form of filters, valves, pressure gauges and automatic control. Velocity of flow through the test chamber is controlled with air pressure from air preparation units and with the location of the regulatory fin at the end of the measuring chamber. The cartridge unit produces a homogeneous mixture of MgO particulates in air. Test results of the axial velocity profile at a distance of L=0.35 m obtained with LDA and PDPA laser equipment and ANSYS FLUENT numerical computations. Important for the combustion process is laminar boundary layer in laminar flow and laminar sublayer in turbulent flow.

2

Experimental and numerical modelling of combustion process of liquid fuels under laminar conditions

Żurek J., Jankowski A.

Journal of KONES

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2014

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Vol. 21, No. 3

309--316

EN

The paper presents the results of experimental studies obtained in a special test stand, which was carried out with the addition of mass flow, summarizes the theoretical analysis of the phenomena occurring in the flow, and the calculations, which were performed using the modeling of flow in the channel. The two examples of model calculations for the two laminar Reynolds number values are shown. Paper presents: channel scheme for analyzing the flow arising as a result of adding mass, two-dimensional diagram of the computational domain with the mass addition, grid computing domain, two-component velocity field, the lines of current in the channel, the distribution of the vector field in the channel, the average velocity as a function of the distances, the speed and temperature distributions for each channel cross-sections for flow with various values of the Reynolds number. The increase in lateral velocity Vb , while maintaining constant lower speed Vd , decreases the thickness of the boundary layer, both the velocity and the thermal one, which was also referenced in experimental investigations, carried out on the special test rig, using LDV and PDPA laser techniques.

3

Laser-Doppler velocimetry - a powerful tool to investigate the flow behavior of polymer melts

Merten A., Schwetz M., Münstedt H.

International Journal of Applied Mechanics and Engineering

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2003

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Vol. 8, no spec.

283-288

EN

The flow behavior of a low density polyethylene (LDPE) and a high density polyethylene (HDPE) melt in the entrance region, the interior of slit, and within a slit die was investigated by means of laser-Doppler velocimetry (LDV). Large vortices were found upstream of the die with for the LDPE. The HDPE did not exhibit any vortices. The velocities within the vortices are about 100 times smaller than those in the center of the flow. Far-reaching consequences for processing arise as the residence time of the melt in the vortices is long. The velocity distribution along the channel axis reveals large elongational deformations near the contraction. The elongational velocities are much higher than those attainable by elongational rheometers. For the HDPE it could be shown that the material slips at the wall.

4

Optical fibre interferometric system for Doppler effect measurement

Jaroszewicz L. R., Krajewski Z.

Opto-Electronics Review

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2002

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Vol. 10, No. 3

185-191

EN

A novel idea of optical fibre laser Doppler velocimetry especially useful for non-contact testing of rotation elements is presented. The main idea of the system is based on an application of interferometric measurement of Doppler effect by a specially constructed optical fibre interferometer. The standard single-mode coupler, connected with laser diode operated at 0.68 µm, has been used as the main optical element. A suitable selection of a target distance from the specially constructed optical head makes the system work as a single-reflection Fabry-Perot fibre interferometer. Such device provided polarisation stability as well as good environmental shielding. The special numerical processing of interferometric output signals by a technique based on FFT gives a possibility of rotation element testing. The theoretical investigation was compared with experimental data obtained for the commercially available magnetic hard disc and the dynamically tuned electromechanical gyro.

5

Pomiar ukrwienia siatkówki oka ludzkiego metodą laserowo-dopplerowską

Badźmirowski K, Borowicz L., Majkowski R., Mocny W., Kasprzak J.

Prace Przemysłowego Instytutu Elektroniki

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2001

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nr 146

152-158

6

Gradually varied flow of unloaded mud in open channel

Nsom B., Debiane K., Piau J. M., Ayadi A.

Applied Mechanics and Engineering

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1999

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Vol. 4, no 3

443-470

EN

We present a theoretical and experimental study of unloaded free surface mudflow in gradually varied conditions. First of all, a polymer gel following the same rheological law as the natural mud was identified, and its severe rheometric characterization was performed. Then the flow of this synthetic mud was generated in a 1-D open channel. The velocity and depth profiles were then systematically investigated. The theoretical study consisted in determining the velocity profiles in terms of the rheological parameters in uniform conditions as well as in determining the form parameter characterizing the gradually varied flow of yield stress fluids in open channels.

7

Measurements of the velocity field of the laminar boundary layer for water free convection along an isothermal vertical flat plate

Shang D. Y., Wang B. X., Takhar H. S.

Applied Mechanics and Engineering

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1998

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Vol. 3, no 4

553-570

EN

The velocity field of laminar free convection for water flowing past an isothermal vertical flat plate is measured for different temperature conditions using the laser Doppler velocimetry. In the experiment, the temperatures on the vertical surface and in the ambient water are controlled at tw=40oC and t*=20oC and tw=60oC and t*=20oC, respectively. The laser Doppler velocimeter is employed using a technique of frequency deviation shift so that it can accurately measure a smaller velocity field of a fluid, such as the velocity of water free convection. For each temperature condition the velocity field wx is measured at heights of 0.05, 0.10, 0.15, and 0.20m. For comparison of the measured results with calculated values, corresponding numerical calculations considering variable thermophysical properties are carried out. By the use of similarity variables, the numerical solutions are transformed to the corresponding dimensionless values, and the experimental data are transformed to the associated dimensionless velocities. The experimental data and the numerical solutions of the velocity field are listed in the tables and plotted in figures. A very good agreement between the measured and calculated values is observed.