EXPERIMENTAL STUDY ON AIR FLOW FIELD CHARACTERISTICS OF SUCTION METERING DEVICE

The vacuum seed metering device absorbs seeds by using the negative pressure generated by vacuum air flow. Therefore, it is of great significance to study the variation law of pyrolysis gas flow field to improve its seed metering performance. In this paper, the common disc and composite disc were selected as the research objects and tested on the indoor test-bed. The negative pressure was measured by U-type barometer, and the effects of fan speed, suction hole size, seed hole structure and air chamber thickness on the air flow field were studied. Firstly, the influence of fan rotation frequency on vacuum chamber negative pressure is studied, and the variation law of negative pressure in vacuum chamber and fan port of common disc and composite disc under the same frequency is compared. Secondly, the suction holes in the vacuum chamber were numbered, the negative pressure distribution of the suction holes was measured, and the influence of the number and diameter of the suction holes on the negative pressure of the vacuum chamber was studied. Finally, the negative pressure was measured at the distance of 0 to 10 mm from the suction hole to study the effect of seed hole structure on the air flow field. Moreover, increase the additional thickness of the vacuum chamber from 0 to 40 mm to study the influence of the chamber thickness on the distribution of the gas flow field. This paper makes a comprehensive experimental analysis on the influencing factors of air flow field of air suction seed metering device, necessary for future design of air suction seed metering device.

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Finite Element Analysis and Experimental Study of Atomized Gas Flow Field in Spray Forming

Materials Physics and Chemistry ◽

10.18282/mpc.v1i4.841 ◽

2020 ◽

Vol 1 (4) ◽

pp. 24

Author(s):

Yongqi Cheng ◽

Yang Bai ◽

Yuhang Chen ◽

Peng Zhang

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Flow Field ◽

Negative Pressure ◽

Gas Flow ◽

Spray Forming ◽

Forming Process ◽

Element Analysis ◽

Pressure Area ◽

Gas Flow Field

<p align="justify">During the spray forming process of die steel, the gas flow field of nozzle atomizer has an important influence on the atomization effect of metal solution and the shape and performance of deposited billet. In this paper, the finite element analysis method was used to study the flow field distribution of the annular slot type restricted nozzle. The results showed that the negative pressure area was formed at the front of the atomizing gas outlet of the nozzle; the negative pressure area was enlarged and the negative pressure value was increased with the increase of the extending position of the liquid guide pipe and the atomizing pressure; when the atomizing pressure was 0.5MPa and the extending position of the liquid guide pipe was 7mm, the negative pressure value of the front of the liquid guide pipe could reach-38650Pa and the gas flow rate could reach 191.4m/s; the back-injection could be effectively avoided by optimizing the appropriate process parameters. And the damage of atomizing nozzle could be reduced.</p><p align="justify"> </p>

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Experimental Analysis of the Two-Phase Unsteady Flow in an Aero-Engine LPP Burner

Volume 2: Turbo Expo 2005 ◽

10.1115/gt2005-68949 ◽

2005 ◽

Author(s):

Mario Caruggi ◽

Edward Canepa ◽

Pasquale Di Martino ◽

Alessandro Nilberto ◽

Marina Ubaldi ◽

...

Keyword(s):

Flow Field ◽

Unsteady Flow ◽

Gas Flow ◽

Air Flow ◽

Scale Model ◽

Fuel Spray ◽

Two Phase ◽

Fuel Droplets ◽

Experimental Campaign ◽

Gas Flow Field

The present paper reports the results of an experimental investigation on the unsteady flow in a Lean Premixed Prevaporized (LPP) burner for aeronautical applications. The experiments were focused on two main aspects: understanding the effect of the fuel spray on the unsteady air flow field and characterizing the fuel spray under unsteady flow conditions in terms of velocity and spatial distribution of the fuel droplets. The experimental campaign was performed with laser-based instrumentation (LDV, PDA and PIV) on a large-scale model of the LPP burner with air preheating and fuel injection in order to allow detailed measurements of the two-phase unsteady flow. The gas flow field is dominated by a spiral vortex breakdown phenomenon, which results in a complex unsteady flow configuration and an extended recirculation zone near the axis of the burner. The fuel droplets flow field is strongly correlated to the gas flow field. By comparing the results of the present experimental campaign with results obtained without fuel spray, there is evidence of a positive effect of the spray on the air flow field. The spray effect results in a reduction of the recirculation phenomenon in the exit section of the LPP burner. At the LPP burner exit a general satisfactory degree of vaporization is obtained. However, at the periphery of the premixing duct outlet section, a significant concentration of larger droplets of not yet vaporized fuel is present, due to the secondary air blast disintegration of the liquid film formed on the internal surface of the premixer tube. This phenomenon is responsible for lack of homogeneity of the fuel distribution in time and space at the premixer duct exit.

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Analysis on Gas Flow Field in Bell-Type Annealing Furnace by Using FLUENT

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.345.581 ◽

2013 ◽

Vol 345 ◽

pp. 581-585 ◽

Cited By ~ 1

Author(s):

Wei Dong Qi ◽

Jin Chun Song ◽

Guang An Ren

Keyword(s):

Flow Field ◽

Negative Pressure ◽

Gas Flow ◽

Splitter Plate ◽

Annealing Furnace ◽

Furnace Annealing ◽

Steel Coil ◽

Protective Gas ◽

Gas Flow Field

Because temperature decreases sharply, expansion caused by heat and contraction caused by cold are evident, the air in furnace is disturbed greatly and the zone of negative pressure may appear during bell-type furnace annealing. The zone can cause external air permeating the furnace and make steel coil annealed. Therefore it is necessary to analyse the flow field of protective gas in furnace during cooling, whether the air zone of negative pressure can form, the location of the zone and the methods of eliminating the zone. In addition, splitter plate disturbs the flow of gas and its effect on disturbed air is also analyzed. This paper analyses flow field in bell-type annealing furnace by using FLUENT, whether the zone of negative pressure exists and its location.

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