Comparison of different configurations of Phase Doppler Analyser
Abstract
A phase Doppler anemometry (PDA) technique is widely used in experimental fluid mechanics to measure size and velocity of particles in the fluid flow. Even though this method is common in experimental fluid mechanics, there are only few techniques that might serve for the purpose of the evaluation of the PDA system. To examine results of the PDA visualizations techniques are usually used. However, this approach suffers from several aspects. Mainly, it is difficult to determine the exact position of the measurement volume of PDA system. Then it is complicated to determine which particles are passing through the measuring volume. Another way how to examine performance of the PDA system is to use two PDA systems simultaneously. By using one laser for both systems we can avoid previously mentioned aspects. In our experiments, we use fiber based PDA system and classical PDA system both made by Dantec Dynamics. The aim of this paper is to compare results from various configurations and highlight crucial parameters that influence measurements.
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Comparison of different configurations of Phase Doppler Analyser Matouš Zaremba1,a, Milan Malý1, Jan Jedelský1 and Miroslav Jícha1 1Brno University of Technology, Faculty of Mechanical Engineering, Department of the thermodynamics and environmental engineering, Technická 2896/2, 616 69 Brno, Czech Republic $EVWUDFW !"# "$#% " ! & # !'"% (% # & """# ")" * #% " & 1 Introduction +, ! # $% ", " & ( % ! " -./ 0 ! " % # *1 % 2 % % ( & ! '"% 3 -4% 5/ $ "3 0 !%# -6/"%""" "3 "# 7 " % # -8/ (% " % * " '"% " 3 &% " #" & 2 Material and Methods Experiments were conducted on the cold test bench at still ambient condition and room temperature at the Brno University of Technology in Sprays laboratory. 2.1 Atomizer The PDA systems were tested in the fully developed spray. The spray was generated by the twin-fluid atomizer, so called outside-in liquid injection atomizer (OIL). This type of atomizer works on a principle of injecting liquid and gas into the mixing chamber where two-phase flow is created. Then this mixture is pushed downstream the atomizer and through the exit orifice into the ambient atmosphere. Detailed description of the atomizer can be found in [6]. Description of the test bench can be found in [7]. Light heating oil (LHO) and pressurized air were used as operating fluids. Physical properties of these fluids are presented in Table 1. Operating regime of the atomizer is determined by the operating overpressure inside the atomizer and liquid and gas mass flows. These parameters were captured during the experiment. Measured values are written in the Table 2. Values of mass flows result in gas to liquid ratio (GLR) of 20% which indicates the annular two-phase flow inside the atomizer [6]. DOI: 10.1051/ C Owned by the authors, published by EDP Sciences, 201 / 0 1 (201 ) 201 epjconf EPJ Web of Conferences , 1 61 6 6 1 10 4 4 2 214 42 2 This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits distribution, and reproduction in any medium, provided the original work is properly cited.
$:; Table 1. Physical properties of used fluids. Name Dynamics v iscosity (kg/(m∙s)) Density (kg/m3 ) Surface tension (kg/s 2 ) LHO 0.0185 874 0.0297 Air 1.82∙ 10 - 5 1.23 - Table 2. Operating regime of the atomizer. LHO mass flow (kg/h) LHO pressure (kPa) Air mass flow (kg/h) Air pressure (kPa) 2.55 66 0.13 69 2.2 Description of examined systems In this work, we examined two phase Doppler analysers in three configurations. The first configuration fiber based 2D phase Doppler analyser made by Dantec Dynamics. This system consists of: x0 0 4<.= # ">;% x><?6. &% " 6@@<% 8.68 " x) " ! 6< (' x><?@. 4 @8 " 8<?@4 8<<% x8=?8<..4 "@<< % xA x)0@<"" "<48B <4=6 & % " 3 &) . B & "0 ) x 8=?.< " 8<< x)0@<" )LJXUH0 C2%)C %C0%C%$C A % A C %DC%'C & " &% x 8=?.< " 8<< x(8@+8< " " < 48 B < 45> 2.2.1. Parameters of the measuring volume &" 7 %, & " & # 4.6 E<<@F<<@F<= & -@/"4 ;# $ * % " 4<< E " 20 G <84 &) 20G<4> )LJXUH( 02142-p.2
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