Experimental investigation of combinational fans influencing on the effective ventilation in an undersea metro interval tunnel

2021 ◽  
pp. 095440622110231
Author(s):  
Siyu Fan ◽  
Shiqiang Chen ◽  
Fangxing Chen ◽  
Feng Tian ◽  
Zhulong Zhu ◽  
...  
Keyword(s):  
Static Pressure ◽  
Symmetry Axis ◽  
Pressure Field ◽  
Exhaust System ◽  
Experimental System ◽  
Large Section ◽  
Symmetrical Distribution ◽  
Effective Ventilation ◽  
Pulling Force ◽  
New Criterion

Based on the metro undersea interval from Wawuzhuang Station to Guizhou Road Station of Qingdao Metro Line 1, a physical model system is built for the sake to further study the Ventilation and Smoke Exhaust System (VSES) of this interval tunnel. In the VSES experimental system, it gains data of variable frequencies inputting to fans, consumed-power values of fans, velocities in carriageways and SEDs (Smoke Exhaust Ducts), static pressure in carriageways under the conditions of the TP (Two Pressing-in) and TP+OE (Two Pressing-in + One Extracted-out) combinations of fans. The experimental data are shown that the static pressure field in horizontal carriageways has a symmetrical distribution, whose symmetry axis is as the plane of a smoke ceiling, whether TP or TP+OE. Under the TP+OE, the velocities in SEDs and carriageways are influenced dominantly by an extracted-out fan; two pressing-in fans of the TP combination influence mainly those velocities. A velocity is capable to dilute and coerce a smog flue. The pushing force of the smog flue is supplied by a pressing-in fan with consumed-power values, and another pressing-in fan with the lower values prevents this flue from another carriageway; furthermore, the pulling force of this flue is supplied by an extracted-out fan with the largest consumed-power values. The ratio of the total values of fans to the discharged volume flow rates in both SEDs is proposed as a new criterion, which can quantify VSES performance and is equivalent to airflow pressure; it is shown that the VSES performance of the TP+OE combination promotes gradually and becomes superior to one of the TP. Finally, it is advisory that the TP+OE should be a preferential combination of fans in designs and engineering situ management of extra length and large section tunnel ventilation.

Development of a Lifetime Pressure Sensitive Paint Procedure for High-Pressure Vane Testing

2021 ◽  
Author(s):  
Papa Aye N. Aye-Addo ◽  
Guillermo Paniagua ◽  
David G. Cuadrado ◽  
Lakshya Bhatnagar ◽  
Antonio Castillo Sauca ◽  
...  
Keyword(s):  
High Pressure ◽  
Test Section ◽  
Static Pressure ◽  
Pressure Field ◽  
Optical Measurements ◽  
Wall Region ◽  
Pressure Amplitude ◽  
Pressure Sensitive Paint ◽  
Suction Surface ◽  
Pressure Sensitive

Abstract Optical measurements based on fast response Pressure Sensitive Paint (PSP) provide enhanced spatial resolution of the pressure field. This paper presents laser lifetime PSP at 20 kHz, with precise calibrations, and results from a demonstration in an annular vane cascade. The laser lifetime PSP methodology is first evaluated in a linear wind tunnel with a converging-diverging nozzle followed by a wavy surface. This test section is fully optically accessible with maximum modularity. A data reduction procedure is proposed for the PSP calibration, and optimal pixel binning is selected to reduce the uncertainty. In the annular test section, laser lifetime PSP was used to measure the time-averaged static pressure field on a section of the suction surface of a high-pressure turbine vane. Tests were performed at engine representative conditions in the Purdue Big Rig for Annular Stationary Turbine Analysis module at the Purdue Experimental Turbine Aerothermal Lab. The 2-D pressure results showed a gradual increase of pressure in the spanwise and flow directions, corroborated with local static pressure taps and computational results. The variation in PSP thickness was measured as a contribution to the uncertainty. The discrete Fourier transform of the unsteady pressure signal showed increased frequency content in wind-on conditions compared to wind-off conditions at the mid-span and 30% span. Compared to the mid-span region, the hub end wall region had an increase in frequencies and pressure amplitude. This result was anticipated given the expected presence of secondary flow structures in the near hub region.

An Investigation of Flow Characteristics and Parameter Effects for a New Concept of Hybrid SVC Nozzle

2018 ◽  
Author(s):  
F. Song ◽  
J. W. Shi ◽  
L. Zhou ◽  
Z. X. Wang ◽  
X. B. Zhang
Keyword(s):  
Static Pressure ◽  
Pressure Ratio ◽  
Flow Characteristics ◽  
Exhaust System ◽  
Aircraft Engine ◽  
Thrust Coefficient ◽  
Thrust Vectoring ◽  
Static Pressure Distribution ◽  
Thrust Vector ◽  
Vector Angle

Lighter weight, simpler structure, higher vectoring efficiency and faster vector response are recent trends in development of aircraft engine exhaust system. To meet these new challenges, a concept of hybrid SVC nozzle was proposed in this work to achieve thrust vectoring by adopting a rotatable valve and by introducing a secondary flow injection. In this paper, we numerically investigated the flow mechanism of the hybrid SVC nozzle. Nozzle performance (e.g. the thrust vector angle and the thrust coefficient) was studied with consideration of the influence of aerodynamic and geometric parameters, such as the nozzle pressure ratio (NPR), the secondary pressure ratio (SPR) and the deflection angle of the rotatable valve (θ). The numerical results indicate that the introductions of the rotatable valve and the secondary injection induce an asymmetrically distributed static pressure to nozzle internal walls. Such static pressure distribution generates a side force on the primary flow, thereby achieving thrust vectoring. Both the thrust vector angle and vectoring efficiency can be enhanced by reducing NPR or by increasing θ. A maximum vector angle of 16.7 ° is attained while NPR is 3 and the corresponding vectoring efficiency is 6.33 °/%. The vector angle first increases and then decreases along with the elevation of SPR, and there exists an optimum value of SPR for maximum thrust vector angle. The effects of θ and SPR on the thrust coefficient were found to be insignificant. The rotatable valve can be utilized to improve vectoring efficiency and to control the vector angle as expected.

Fast method for computation of the static pressure field in stenotic geometries by PC MRI

2003 ◽  
Author(s):  
Abbas N. Moghaddam ◽  
Nasser Fatouraee ◽  
Eric T. Choi ◽  
Amir A. Amini
Keyword(s):  
Static Pressure ◽  
Pressure Field ◽  
Fast Method

Numerical Study of Pressure Loss in Ceramic Bed of Thermal Flow Reversal Reactor

2013 ◽  
Vol 655-657 ◽  
pp. 149-153
Author(s):  
Zhen Qiang Gao ◽  
Rui Xiang Liu ◽  
Yong Qi Liu
Keyword(s):  
Pressure Loss ◽  
Static Pressure ◽  
Pressure Field ◽  
Numerical Study ◽  
Volume Flow Rate ◽  
Flow Reversal ◽  
Thermal Flow ◽  
Dimensional Model ◽  
Model Fluid ◽  
Main Factors

This paper describes the use of a commercial CFD code, FLUENT, to model fluid flow in thermal flow reversal reactor (TFRR) for lean methane oxidation. A two dimensional model is used. Pressure loss in ceramic bed of TFRR was focused on, and the effects of main factors are presented. The results show that the contours of static pressure in ceramic bed are slightly inclined due to the gradually variation distribution of velocity; the pressure field in distributing header is more uniform than that of collecting header; the ratio of header’s height to ceramic length influences the pressure loss most and with the increase of the ratio the pressure loss of TFRR decreased dramatically; the pressure loss increased with the increase of volume flow rate. The structure of headers is the most important factor which affects the pressure loss of TFRR.

Experimental Investigation of Flow Induced Rotor Oscillations in a Centrifugal Sewage Water Pump

Volume 3 ◽  
2004 ◽  
Author(s):  
Friedrich-Karl Benra ◽  
Hans Josef Dohmen ◽  
Oliver Schneider
Keyword(s):  
Experimental Investigation ◽  
Static Pressure ◽  
Pressure Field ◽  
Pressure Fluctuations ◽  
Sewage Water ◽  
Water Pump ◽  
Flow Rates ◽  
Pump Rotor ◽  
Pump Shaft ◽  
Impeller Geometry

Most of the pumps for sewage transport have a special impeller geometry in order to avoid operational disturbances by clogging. The almost exclusively used single stage machines particularly are equipped with single-blade impellers. With this impeller geometry a strongly uneven pressure field along the perimeter of the pump casing can be expected. The resulting periodically unsteady flow forces affect the impeller and produce strong radial deflections of the pump shaft. In this contribution the experimental investigation of the dynamic behavior of the pump rotor as a consequence of the transient hydrodynamic forces is described. To verify the calculated rotor oscillations measurements were performed at several rotating speeds and at different volume flow rates. The pump which before has been investigated numerical was equipped with several sensors. The deflections of the pump rotor were measured with two proximity sensors. The measurement of the vibration accelerations at the pump casing showed the effects of the transient hydrodynamic stimulation forces. Measurements of the static pressure in the casing allowed a correlation between the rotor oscillations and the pressure fluctuations produced by the single-blade impeller.

Dynamics and motion of a gas bubble in a viscoplastic medium under acoustic excitation

2019 ◽  
Vol 865 ◽  
pp. 381-413 ◽  
Author(s):  
G. Karapetsas ◽  
D. Photeinos ◽  
Y. Dimakopoulos ◽  
J. Tsamopoulos
Keyword(s):  
Effective Viscosity ◽  
Acoustic Pressure ◽  
Static Pressure ◽  
Pressure Field ◽  
Spherical Shape ◽  
Lagrangian Formalism ◽  
Acoustic Excitation ◽  
Bubble Motion ◽  
Viscoplastic Material ◽  
Simplified Approach

We investigate the dynamics of the buoyancy-driven rise of a bubble inside a viscoplastic material when it is subjected to an acoustic pressure field. To this end, we develop a simplified model based on the Lagrangian formalism assuming a pulsating bubble with a spherical shape. Moreover, to account for the effects of a deformable bubble, we also perform detailed two-dimensional axisymmetric simulations. Qualitative agreement is found between the simplified approach and the detailed numerical simulations. Our results reveal that the acoustic excitation enhances the mobility of the bubble, by increasing the size of the yielded region that surrounds the bubble, thereby decreasing the effective viscosity of the liquid and accelerating the motion of the bubble. This effect is significantly more pronounced at the resonance frequency, and it is shown that bubble motion takes place even for Bingham numbers (Bn) that can be orders of magnitude higher than the critical Bn for bubble entrapment in the case of a static pressure field.

1/4 Scale Hot Flow Model Test of a GE LM2500 Exhaust System

1992 ◽  
Author(s):  
D. Vandam ◽  
A. M. Birk
Keyword(s):  
System Performance ◽  
Flow Model ◽  
Static Pressure ◽  
Exhaust System ◽  
Engine Exhaust ◽  
Static Pressure Distribution ◽  
Sample Data ◽  
Infrared Signature ◽  
Mass Flow Rates ◽  
Cooling Air

A facility has been constructed to test exhaust systems for the GE LM2500 Gas Turbine. The facility is capable of simulating the hot flow exhaust conditions for the LM2500 in 1/4 scale. The facility was constructed to study LM2500 exhaust system performance including the effects of small changes in the geometry of the LM2500 exhaust collector and also to study the effects of devices such as infrared signature suppressors on the overall exhaust system performance. The facility is currently instrumented to measure local static and total pressures, local swirl angles, exit plane total and static pressure distribution, and primary (engine exhaust) and secondary (enclosure cooling air) mass flow rates. The facility has been constructed to accommodate a variety of exhaust uptake geometries. Tests were recently conducted to study certain aspects of exhaust system performance. Sample data is presented and comparisons are made with other available data.

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