An Experimental Study on the Analysis of Operating Conditions in the PEMFC Flow Channel by Observing Temperature/Humidity Field

2021 ◽  
Author(s):  
Jaesu Han ◽  
Dongjin Yu ◽  
Sangseok Yu
Keyword(s):  
Experimental Study ◽  
Flow Channel ◽  
Operating Conditions ◽  
Humidity Field

Experimental Study on Quadruped Wheel Robot for Wheat Precision Seeding

2016 ◽  
Vol 693 ◽  
pp. 1651-1657 ◽  
Author(s):  
Hai Bo Lin ◽  
Chui Jie Yi ◽  
Zun Min Liu
Keyword(s):  
Experimental Study ◽  
Field Test ◽  
Design Method ◽  
Operating Conditions ◽  
High Yield ◽  
Orthogonal Rotation ◽  
Agricultural Machine ◽  
Main Factors ◽  
Multiple Effort

The wheat precision seeding technology provided an advanced agricultural protection for the high yield of wheat. But the lack of an effective agricultural machine made this technology difficult to apply widely. In this paper a quadruped wheel robot to achieve the wheat precision seeding technology was designed. And experimental study was taken under different operating conditions. Because of multiple effort factors, a quadratic orthogonal rotation combination design method was applied in the experiments, and identifying the main factors by analysis. Then the field test was carried out according to the main factors. The experiment results showed that the qualified rates of seeding exceed 93% in different sowing speed. That reached the agronomic requirements of wheat precision seeding.

Effects of Manufacturing Tolerances on Regenerative Exchanger Number of Transfer Units and Entropy Generation

2005 ◽  
Vol 128 (3) ◽  
pp. 585-598 ◽  
Author(s):  
Wei Shang ◽  
Robert W. Besant
Keyword(s):  
Entropy Generation ◽  
Flow Channel ◽  
Operating Conditions ◽  
Channel Diameter ◽  
Pressure Drops ◽  
Entropy Generation Number ◽  
Compact Heat Exchangers ◽  
Prime Concern ◽  
Manufacturing Tolerances ◽  
The Impact

A prime concern with the design of ultra-compact heat exchangers is the impact on performance of flow channel variations due to flow channel hydraulic diameter variations caused by manufacturing tolerances. This paper uses analytical methods to show that as the standard deviation in flow channel sizes, caused by manufacturing tolerances in a rotary regenerative exchanger, is increased compared to the average flow channel diameter the effective number of transfer units decreases. Depending on the operating conditions, the entropy generation number either increases or decreases with increasing flow channel size variations. These findings extend previous findings that showed that flow channel variations cause lower pressure drops and effectiveness.

Research of throwing areols of underground pipeline in permafrost

2021 ◽  
pp. 21-30
Author(s):  
T. S. Sultanmagomedov ◽  
◽  
R. N. Bakhtizin ◽  
S. M. Sultanmagomedov ◽  
T. M. Halikov ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Experimental Study ◽  
Finite Element ◽  
Strain State ◽  
Operating Temperature ◽  
Operating Conditions ◽  
Loss Of Stability ◽  
Underground Pipeline ◽  
The Finite Element Method ◽  
Permafrost Thawing

Study is due to the possibility of loss of stability of the pipeline in the process of pumping a product with a positive operating temperature and the formation of thawing halos. The article presents the ways of solving the thermomechanical problem of pipeline displacement due to thawing. The rate of formation of a thawing halo is investigated depending on the initial temperatures of the soil and the pumped product. The developed monitoring system makes it possible to study the rate of occurrence of thawing halos in the process of pumping the product. An experimental study on the formation of thawing halos around the pipeline was carried out on an experimental model. A thermophysical comparative calculation of temperatures around the pipeline on a model by the finite element method has been carried out. Keywords: underground pipeline; permafrost; thawing halo; monitoring; operating conditions; stress–strain state.

scholarly journals Improvement of Pump Performance at Off-Design Conditions

1985 ◽  
Author(s):  
J. Paulon ◽  
C. Fradin ◽  
J. Poulain
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
Mass Flow ◽  
Flow Characteristic ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Pump Performance ◽  
Wide Range ◽  
Mass Flows ◽  
Design Value

Industrial pumps are generally used in a wide range of operating conditions from almost zero mass flow to mass flows larger than the design value. It has been often noted that the head-mass flow characteristic, at constant speed, presents a negative bump as the mass flow is somewhat smaller than the design mass flows. Flow and mechanical instabilities appear, which are unsafe for the facility. An experimental study has been undertaken in order to analyze and if possible to palliate these difficulties. A detailed flow analyzis has shown strong three dimensional effects and flow separations. From this better knowledge of the flow field, a particular device was designed and a strong attenuation of the negative bump was obtained.

Noise Attenuation Potential Using Helmholtz Absorbers Integrated in Low Pressure Turbine Exit Guide Vanes and Turbine Exit Casing End Walls

2020 ◽  
Author(s):  
Manuel Zenz ◽  
Loris Simonassi ◽  
Philipp Bruckner ◽  
Simon Pramstrahler ◽  
Franz Heitmeir ◽  
...  
Keyword(s):  
Suction Side ◽  
Aircraft Engine ◽  
Low Pressure ◽  
Flow Channel ◽  
Operating Conditions ◽  
Noise Attenuation ◽  
Beneficial Result ◽  
Guide Vanes ◽  
Acoustic Liners ◽  
Low Pressure Turbine

Abstract To further reduce the noise emitted from modern aircrafts, every possibility has to be taken into account. Acoustic liners are successfully used in the inlet or the bypass duct of aircraft engines to mitigate the noise emitted by the fan. Due to the rough environment (high temperature, flow velocity, higher order duct modes), the exhaust duct is of limited use concerning the application of acoustic liners. It is well known that the last stage low pressure turbine (LPT) has a dominant influence onto the emitted noise of an aircraft engine especially at low load conditions such as approach. A noise reduction in this area could lead to a beneficial result of decreasing the noise content which is directly emitted in the environment. This paper is about noise attenuation using Helmholtz absorbers in various parts of a turbine exit casing (TEC). These single degree of freedom absorbers have been integrated in turbine exit guide vanes (TEGVs), with the openings on the vanes suction side, as well as in the inner and outer duct end walls. Different absorber neck diameters were investigated and combined with different vane designs. The vane designs studied included a state of the art set-up as well as vanes with a lean. Test runs were performed with altered combinations of vanes and end walls under engine relevant operating conditions in a subsonic test turbine facility for aerodynamic, aeroacoustic and aeroelastic investigations (STTF-AAAI) located at the Institute of Thermal Turbomachinery and Machine Dynamics at Graz University of Technology. Comparisons between all these setups and the respective hard wall reference cases were done. The resulting sound pressure levels as well as sound power levels of all investigated combinations are listed and compared concerning each configurations noise attenuation potential. Additionally, the flow field downstream of every setup is analysed if the aerodynamic behaviour is changing. The investigated operating point is the noise certification point Approach (APP) which is of high importance because of the high acoustical impact onto the environment around airports during the landing procedure of an aircraft. The acoustical data has been obtained by using flush mounted condenser microphones located downstream of the TEC. The whole test section was rotated over 360 deg around the flow channel. To detect if the aerodynamical behaviour changes by including openings into the flow channel end walls as well as into the vanes, aerodynamic measurements have been performed downstream of the TEC. The aerodynamical data was obtained by using an aerodynamic five-hole-probe (5HP) as well as a trailing edge probe.

Experimental study of fibre breakup and shot formation in melt blowing nozzle designs

2020 ◽  
pp. 152808372094927 ◽  
Author(s):  
Ignacio Formoso ◽  
Alejandro Rivas ◽  
Gerardo Beltrame ◽  
Gorka S Larraona ◽  
Juan Carlos Ramos ◽  
...  
Keyword(s):  
Experimental Study ◽  
High Speed ◽  
Flux Ratio ◽  
Adhesive Bond ◽  
Operating Conditions ◽  
Nozzle Geometry ◽  
Dimensionless Temperature ◽  
Melt Blowing ◽  
High Speed Imaging ◽  
Adhesive Bonds

The high demand for quality in the manufacture of absorbent hygiene products requires the adhesive bonds between layers to be as uniform as possible. An experimental study was conducted on two industrial multihole melt blowing nozzle designs used for hot-melt adhesive applications for hygiene products, in order to study two defects that influence the quality of the adhesive bond: fibre breakup, resulting in contamination, and the presence of shots, undesirable lumps that end up in the finished product. To this end, the fibre dynamics were captured at the nozzle exit region by using high-speed imaging. From the results it was observed that die drool is the main source of shot formation, while fibre breakup occurs as a result of applying a sufficiently large force in the direction perpendicular to the fibre. In addition, three dimensionless parameters were defined, the first two being the air-polymer flux ratio and the dimensionless temperature ratio, both of which represent the operating conditions, and the remaining one being the force ratio, which represents the nozzle geometry. The effect of these parameters on fibre breakup and shot formation was studied and the results indicate that both the operating conditions and the nozzle geometry were responsible for the onset of the fibre breakup and for the formation of shots. More precisely, both defects turned out to be dominated by the air-polymer flux ratio and the air tilt angle. The results that emerge from this study are useful for the enhancement of industrial melt blowing nozzles.

Simulation and experimental study of thermal storage systems for district cooling system under commercial operating conditions

Energy ◽  
2020 ◽  
Vol 203 ◽  
pp. 117781
Author(s):  
Y.L. Shao ◽  
K.Y. Soh ◽  
Y.D. Wan ◽  
M. Kumja ◽  
Z. Khin ◽  
...  
Keyword(s):  
Experimental Study ◽  
Cooling System ◽  
Storage Systems ◽  
Thermal Storage ◽  
Operating Conditions
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