Mono-Dispersed Water Droplet Delivery in a Small-Scale Refrigerated Wind Tunnel

Author(s):  
Kyle Hutchings ◽  
David Thompson ◽  
Stefan Jung ◽  
Dominik Raps
2021 ◽  
pp. 1-16
Author(s):  
Ojing Siram ◽  
Niranjan Sahoo ◽  
Ujjwal K. Saha

Abstract The small-scale horizontal-axis wind turbines (SHAWTs) have emerged as the promising alternative energy resource for the off-grid electrical power generation. These turbines primarily operate at low Reynolds number, low wind speed, and low tip speed ratio conditions. Under such circumstances, the airfoil selection and blade design of a SHAWT becomes a challenging task. The present work puts forward the necessary steps starting from the aerofoil selection to the blade design and analysis by means of blade element momentum theory (BEMT) for the development of four model rotors composed of E216, SG6043, NACA63415, and NACA0012 airfoils. This analysis shows the superior performance of the model rotor with E216 airfoil in comparison to other three models. However, the subsequent wind tunnel study with the E216 model, a marginal drop in its performance due to mechanical losses has been observed.


10.14311/530 ◽  
2004 ◽  
Vol 44 (2) ◽  
Author(s):  
A. V. Petrov ◽  
Y. G. Stepanov ◽  
M. V. Shmakov

This report presents the results of experimental investigations into the interaction between the propellers (Ps) and the airframe of a twin-engine, twin-boom light transport aircraft with a Π-shaped tail. An analysis was performed of the forces and moments acting on the aircraft with rotating Ps. The main features of the methodology for windtunnel testing of an aircraft model with running Ps in TsAGI’s T-102 wind tunnel are outlined.The effect of 6-blade Ps slipstreams on the longitudinal and lateral aerodynamic characteristics as well as the effectiveness of the control surfaces was studied on the aircraft model in cruise and takeoff/landing configurations. The tests were conducted at flow velocities of V∞ = 20 to 50 m/s in the ranges of angles of attack α =  -6 to 20 deg, sideslip angles of β = -16 to 16 deg and blade loading coefficient of B 0 to 2.8. For the aircraft of unusual layout studied, an increase in blowing intensity is shown to result in decreasing longitudinal static stability and significant asymmetry of the directional stability characteristics associated with the interaction between the Ps slipstreams of the same (left-hand) rotation and the empennage.


1976 ◽  
Vol 21 (3) ◽  
pp. 2-12
Author(s):  
Jan M. Drees

This paper presents an overview of the correlation of helicopter rotor performance and loads data from various tests and analyses. Information is included from U.S. Army‐sponsored tests conducted by Bell Helicopter Company for free‐flight full‐scale tests in the NASA‐Ames 40 × 80 wind tunnel, one‐fifth scale tests in the NASA‐Langley Transonic Dynamics Tunnel, and small‐scale tests of a rotor in air. These test data are compared with each other, where appropriate, and with calculated results. Typical examples illustrate the state of the art for correlation and indicate anomalies encountered. It is concluded that a procedure using theoretical analyses to aid in interpretation and evaluation of test results is essential to developing a science of correlation.


1998 ◽  
Vol 26 ◽  
pp. 212-216 ◽  
Author(s):  
Florence Naaim-Bouvet ◽  
Mohamed Naaim

This paper deals with the influence of the vertical and horizontal variation of Aeolian snow flux on estimations of snow-storm duration and on snowdrift patterns simulated in a wind tunnel.First of all, we shall review recent developments, including our own simulations, concerning the horizontal increase of mass flux until drifting-snow saturation has been reached.Next, after a critical examination of various snowdrift-modelling criteria, we present the results of an experiment undertaken in our wind tunnel: We studied cross-section drill-area changes behind a small-scale snow fence as a function of time for different fetches but for the same mean wind speed at the beginning of the testing section. For each fetch, we carried out vertical profiles of sand particles using image processing and we studied the geometrical parameters of the drift. We conclude dial changes in the cross-section drift area depend on the ablation length and if particle saturation is not reached, the use of a storm-duration scale leads to Overevaluation of prototype storm duration. Moreover, we point out that drift pattern vary as a function of the concentration profiles.


1998 ◽  
Vol 26 ◽  
pp. 212-216 ◽  
Author(s):  
Florence Naaim-Bouvet ◽  
Mohamed Naaim

This paper deals with the influence of the vertical and horizontal variation of Aeolian snow flux on estimations of snow-storm duration and on snowdrift patterns simulated in a wind tunnel.First of all, we shall review recent developments, including our own simulations, concerning the horizontal increase of mass flux until drifting-snow saturation has been reached.Next, after a critical examination of various snowdrift-modelling criteria, we present the results of an experiment undertaken in our wind tunnel: We studied cross-section drill-area changes behind a small-scale snow fence as a function of time for different fetches but for the same mean wind speed at the beginning of the testing section. For each fetch, we carried out vertical profiles of sand particles using image processing and we studied the geometrical parameters of the drift. We conclude dial changes in the cross-section drift area depend on the ablation length and if particle saturation is not reached, the use of a storm-duration scale leads to Overevaluation of prototype storm duration. Moreover, we point out that drift pattern vary as a function of the concentration profiles.


Author(s):  
Alessandro Bianchini ◽  
Francesco Balduzzi ◽  
Giovanni Ferrara ◽  
Lorenzo Ferrari ◽  
Giacomo Persico ◽  
...  

Darrieus vertical axis wind turbines (VAWTs) have been recently identified as the most promising solution for new types of applications, such as small-scale installations in complex terrains or offshore large floating platforms. To improve their efficiencies further and make them competitive with those of conventional horizontal axis wind turbines, a more in depth understanding of the physical phenomena that govern the aerodynamics past a rotating Darrieus turbine is needed. Within this context, computational fluid dynamics (CFD) can play a fundamental role, since it represents the only model able to provide a detailed and comprehensive representation of the flow. Due to the complexity of similar simulations, however, the possibility of having reliable and detailed experimental data to be used as validation test cases is pivotal to tune the numerical tools. In this study, a two-dimensional (2D) unsteady Reynolds-averaged Navier–Stokes (U-RANS) computational model was applied to analyze the wake characteristics on the midplane of a small-size H-shaped Darrieus VAWT. The turbine was tested in a large-scale, open-jet wind tunnel, including both performance and wake measurements. Thanks to the availability of such a unique set of experimental data, systematic comparisons between simulations and experiments were carried out for analyzing the structure of the wake and correlating the main macrostructures of the flow to the local aerodynamic features of the airfoils in cycloidal motion. In general, good agreement on the turbine performance estimation was constantly appreciated.


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