機(jī)械設(shè)計(jì)畢業(yè)論文翻譯--氣舉泵提升固態(tài)物的性能檢測(cè)（英文）

1、Hitoshi Fujimoto Department of Energy Science and Technology, Graduate School of Energy Science, Kyoto University, Kyoto 606-8501, JapanSatoshi Ogawa Graduate Student at Kyoto University (Presently, Toyota Motor Corp.)Hi

2、rohiko Takuda Department of Energy Science and Technology, Graduate School of Energy Science, Kyoto University, Kyoto 606-8501, JapanNatsuo Hatta Department of Civil Engineering, Nippon-Bunri University, Oita, JapanOpera

3、tion Performance of a Small Air-Lift Pump for Conveying Solid ParticlesThe pump performance of a small air-lift system for conveying solid particles is investi- gated experimentally. The total length of the vertical lift

4、ing pipe is 3200 mm, and the inner diameter of the pipe is 18 mm. The gas injector is set at a certain point of the pipe. The flows in the lifting pipe are water/solid two-phase mixtures below the gas injection point, an

5、d air/water/solid three-phase mixtures above it. The time-averaged characteris- tics of the flows are examined for various experimental conditions. The effects of particle diameter, particle density, the gas-injection po

6、int, and the volume flux of air on the pump performance are studied systematically. The critical boundary at which the particles can be lifted is discussed in detail based upon one-dimensional mixture model. ?DOI: 10.111

7、5/1.1514498?Keywords: Air-Lift Pump, Gas/Liquid/Solid Three-Phase Flow, Particle Size, Gas-Injection Point, Critical Boundary of Transport of Solid Particles1 IntroductionAir-lift pumps are utilized to transport explosiv

8、e/toxic liquids in chemical industries, and to convey slurries in mining industries ?1?. The utilization of air-lift pumps has also been employed for lifting marine mineral resources such as manganese nodules from the de

9、ep-sea bed to the sea surface ?2?. The air-lift pumps consist of vertical lifting pipes and gas injectors ?see Fig. 1?. The upward flow of mixtures in the vertical pipes arises from the buoyancy of the injected gas in th

10、e liquid. The flow of the gas-liquid two-phase or gas-liquid-solid three-phase mixtures in the pipes is unsteady and chaotic in nature. Thus, the transport phenomena are very complicated despite the simple pump mechanism

11、. To date, the performance of air-lift pumps has been studied experimentally as well as theoretically. Since the present study treats the air-lift pump for conveying solid particles, prior experi- mental studies concerne

12、d with this are cited briefly. Weber and Dedegil ?3? performed experiments using a large-scaled air-lift pump whose length was from 50 to 441 m with a diameter of 300 mm. Three kinds of solid particles were used. They me

13、asured the volume of discharged particles for different gas injection points. Saito et al. ?4? studied the operation performance of air-lift pumps changing the pipe length from 7.7 m to 196.6 m. They also varied the pipe

14、 diameter from 46.7 mm to 154 mm. Kato et al. ?5?, Yoshinaga et al. ?6?, Yoshinaga and Sato ?7?, and Hatta et al. ?8? carried out the experiments using relatively small air lift pumps for conveying solid particles in ord

15、er to vali- date their theoretical models for predicting the operating perfor- mance of the pumps. The total pipe length was less than 10 m in their experiments. Kawashima et al. ?9? examined the relationship between the

16、 volumetric fluxes of supplied air and discharged par- ticles under the condition that the lifting pipe was 6 m in length and 50 mm in diameter, and crushed rocks ?about 1.7 mm in diameter? were used as solid particles.

17、The operation performance of air-lift pumps for conveying solid particles depends upon many factors, for example, the scale of lifting pipes, the physical properties of liquid- and solid-phases, the size of solid particl

18、es, the volume of supplied air, and the submergence ratio ?6,7?. Since the pump power of air-lift systems is small compared to mechanical pumps, such factors can affectthe pump operation drastically. Thus, the operation

19、conditions of the air-lift pumps must be carefully chosen to suit their actual use. In order to determine proper operating conditions, systematic ex- periments are essential. However, there is still insufficient experi-

20、mental data in the literature concerning the flow characteristics of gas-liquid-solid mixtures, despite many prior studies. Further- more, in designing air-lift pumps for conveying solid particles, one of the important r

21、equirements is to estimate the critical boundary at which the solid particles can be transported. This has not yet been investigated experimentally in detail. In the present study, the operation performance of a relative

22、ly small air-lift pump for conveying solid particles is investigated. The total length of the lifting pipe is 3200 mm and its inner diameter is 18 mm. The time-averaged characteristics of the mix- tures in the pipe are e

23、xamined under stable pump-operating con- ditions. Emphasis is placed on the critical boundary at which the solid particles can be lifted along the pipe. We also intend to provide useful experimental data for the air-lift

24、 pump system. In order to do so, the particle size, the particle density, the gas injec- tion point, and the supplied gas flux on the pump performance are systematically changed as parameters. The transport phenomena of

25、gas-liquid-solid mixtures will be discussed from both experi- mental and theoretical viewpoints.2 Experimental MethodFigure 1?a? shows a schematic of the experimental apparatus. The body of the air-lift pump consists of

26、a lifting pipe, a reservoir, a suction box, a chamber to inject air into the lifting pipe ?gas- injector?, a particle feeder, and an air separator. The total length, L, of the lifting pipe made of transparent plastic is

27、3200 mm. The inner diameter of the pipe, D, is 18 mm. The gas injector is set at a certain point of the pipe. The bottom end of the lifting pipe is connected to the reservoir through a sufficiently large pipe of diameter

28、 146 mm. Water is continuously supplied to the reservoir at the top end during experiments. The water surface level in the reservoir is maintained at LS?2420 mm away from the top of the suction box by discharging excess

29、water through an overflow pipe. Since the inner diameter of the reservoir ??146 mm? is much larger than that of the lifting pipe, the downward flow in the reservoir is very slow compared to the upward flow in the lifting

30、 pipe. As such, the flow in the reservoir negligibly affects the operation performance of the pump.Contributed by the Petroleum Division for publication in the JOURNAL OF EN-ERGY RESOURCES TECHNOLOGY. Manuscript received

31、 by the Petroleum Division; Jun. 2001; revised manuscript received Jun. 2002. Associate Editor: J. K. Keska.Copyright © 2003 by ASME Journal of Energy Resources Technology MARCH 2003, Vol. 125 Õ 17Downloaded Fr

32、om: http://materialstechnology.asmedigitalcollection.asme.org/ on 04/16/2015 Terms of Use: http://asme.org/termsSpherical solid particles made of alumina or glass, in the par- ticle feeder, are supplied to the suction bo

33、x through the pipe, together with some water. The material density, ?S , is 3600 kg/m3for alumina, and 2500 kg/m3 for glass, respectively, and the par- ticle diameters, dS , used in the experiments are 2, 3, and 5 mm. Th

34、e volume rate of supplied particles is controlled by the volume of water and the number of revolutions of the screw, which is set at the bottom of the particle feeder. Both the particles and water are sucked into the lif

35、ting pipe though the bottom-end of the suc- tion pipe. Compressed air is supplied to the chamber through an air filter and a mass flow controller. The air is injected into the lifting pipe from the chamber. Details of th

36、e gas injector are explained below. The gas injection point, Lg , from the suction box is set at Lg ?270 mm, 800 mm, 1300 mm, or 2000 mm in order to examine the effect of gas-injection point on operating performance. At

37、the outlet of the pipe, the air is released to the surrounding atmosphere. Experiments are carried out under stable pump-operating con- dition that the flow rate of the injected air is maintained at a preset value. In su

38、ch cases, the mean volume flow rate for water is also kept almost constant. Thus, the measurement of mean flow prop- erties is performed under the stable operating condition. The vol- ume flow rate of the air is regulate

39、d and measured by the gas mass flow controller. The volume rate of the supplied air is represented by the gas volumetric flux ?superficial velocity?, jGa , reduced to the atmospheric state. It is within the range of 0 m/

40、s ?jGa ?3.27 m/s due to the capacity of the air-compressor. The mea- surement accuracy of jGa is within ?0.03 m/s. The volume flow rate of water, QL , is determined by the vol- ume of discharged water and the sampling ti

41、me, while the mass flow rate of solid particles, M S , is measured by the discharged particle mass and the sampling time. The volume of discharged water is directly measured by a volumeter. The discharged particle mass i

42、s measured by a scale, after the discharged wet particles are dried using hot-air dryer. In addition, the sampling times em- ployed are 10 or 20 seconds. The volumetric fluxes ?superficial velocities?, jS , for solid- ph

43、ase and jL , for liquid-phase are determined as follows,jS? M S ?SA , jL? QL A (1)in which A denotes the cross-sectional area of the lifting pipe. The measurement uncertainties of jL and M S are within ?0.01 m/s, and ?0.

44、002 kg/s, respectively. It should be noted that both jL and jS are time-averaged values. The gas flow rate and the particle flow rate are controllable, but the water flow rate cannot. Thus, the gas- and particle-flow rat

45、es are varied systematically as parameters to examine the pump per- formance. Since the measured water flow rates scatter slightly under a fixed experimental condition, four runs or more are per- formed, and the arithmet

46、ic mean values of jL are determined. In almost cases, the dispersion of jL is appreciably larger than the measurement uncertainty. Both the dispersion of jL and the mea- surement uncertainty are taken into account for dr

47、awing the error- bands of jL in Figures 2, 4, 5, 7, and 8. Figure 1?b? shows a gas-injector attached to a vertical pipe. Air is injected into the chamber through two round 5 mm diameter intake ports, and temporarily stor

48、ed there. The air is then injected into the lifting pipe through several holes bored at regular inter- vals along the circumferential direction. Since there is the possi- bility that the hole diameter of the gas-injector

49、 as well as the number of holes affect the pump performance, some preliminary experiments were carried out and are described in the following paragraphs. Figure 2?a? shows the effect of the gas-injector hole diameter on

50、discharged water flux in the case of gas-liquid two-phase flow (jS?0 m/s). When the gas-injection point is set at Lg?270 mm, and the number of holes is four, it is found that the hole diameteraffects the discharged water

51、 flux very slightly. The mean relative pressures, PG , in the chamber to the atmospheric one are listed in Table 1. The relative pressure for case 1 is higher than the other cases because of the small hole diameter. Figu

52、res 2?b? and ?c? show the effect of the number of holes on the water flux for the case of gas-liquid two-phase flow ?b? and gas-liquid-solid three-phase flow ?c?, respectively. The number of holes is one or four. Alumina

53、 particles of diameter 3 mm are used as the solid-phase. The gas-injection point is set at Lg?270 mm. The effect of the number of holes cannot be seen on the dis- charged water in either case of gas-liquid two-phase flow

54、 and gas-liquid-solid three-phase flow. Therefore, it is confirmed from these results that the effect of the gas-injection method on theFig. 2 Effect of the gas injection method on pump performanceTable 1 Pressure in the

55、 chamberGas flux: jGa, m/sPressure in the chamber: PG, MPaCase 1: ?1 mm?4 Case 2: ?3 mm?4 Case 3: ?5 mm?4 Case 4: ?10 mm?40.33 0.022 0.021 0.021 0.020 0.65 0.023 0.020 0.021 0.020 0.98 0.030 0.020 0.021 0.020 1.31 0.035

56、0.019 0.021 0.020 1.64 0.044 0.019 0.021 0.020 1.96 0.053 0.019 0.021 0.020 2.29 0.064 0.020 0.021 0.020 2.62 0.076 0.020 0.021 0.020 2.95 0.089 0.020 0.021 0.020 3.27 0.102 0.020 0.021 0.020Journal of Energy Resources T