Influences of Impeller Diameter and Diffuser Blades on Air-Water Two-Phase Flow Performance of Centrifugal Pump

2005 ◽  
Author(s):  
Naoki Matsushita ◽  
Akinori Furukawa ◽  
Kusuo Okuma ◽  
Satoshi Watanabe
Keyword(s):  
Centrifugal Pump ◽  
Water Flow ◽  
Flow Rate ◽  
Rotational Speed ◽  
Flow Condition ◽  
High Performance ◽  
Two Phase Flow ◽  
Water Flow Rate ◽  
Phase Flow ◽  
Two Phase

A tandem arrangement of double rotating cascades and single diffuser cascade, proposed as a centrifugal pump with high performance in air-water two-phase flow condition, yields lower head due to the smallness of the impeller outlet in comparison with a impeller with large outlet diameter and no diffuser. Influences of impeller diameter change and installation of diffuser blades on two-phase flow performance were experimentally investigated under the case of the same volute casing. As the result, the similarity law of the diameter of impeller having the similar blade geometry and the rotational speed is satisfied even in two-phase flow condition. Comparing pump performances between a large impeller without diffuser blades and a small one with diffuser blades, higher two-phase flow performance is obtained by controlling the rotational speed of a small impeller with diffuser blades in the range of small water flow rates, while a large impeller with no diffuser gives high performance in the range of high water flow rate and small air flow rate.

Development of Air/Water Two-Phase Flow Centrifugal Pump and Its Operating Characteristics

2003 ◽  
Author(s):  
Akinori Furukawa ◽  
Satoshi Ohshita ◽  
Kusuo Okuma ◽  
Satoshi Watanabe
Keyword(s):  
Water Flow ◽  
Flow Rate ◽  
Two Phase Flow ◽  
Air Flow ◽  
Water Flow Rate ◽  
Phase Flow ◽  
Air Flow Rate ◽  
Operating Characteristics ◽  
Two Phase ◽  
Flow Pump

A centrifugal impeller, the pumping action of which could be highly kept even at an air-water two-phase flow condition of inlet void fraction more than 30% in the region of relatively high water flow rate, has been developed. In the present paper, the design concept of two-phase flow impeller is described, at first, with experimental results. The short bladed forward impeller with high outlet blade angle was decided to keep theoretical head higher even in two-phase flow condition and to disperse the air accumulating region on the suction blade surface by the water jet flow coming from the pressure side. Furthermore, the tandem arrangement of outer and inner rotating cascades with the same blade numbers was adopted to suppress the rotating stall phenomena appearing in the case of a single stage of outer cascade. It should be noted that these results were obtained with operating a boost pump installed upstream of mixing section of air and water, that is not an actual operation of two-phase flow pump. Secondly, the operating characteristics of this two-phase flow pump with change of air flow rate were investigated experimentally without operating the boost pump. As the trajectory of operating point with increasing air flow rate appears along the resistance curve of piping system, the impossibility of pumping occurs at lower air flow rate even though pump head takes a positive value at high air flow rate with increasing water flow rate. It is recognized that it is necessary to improve two-phase flow head characteristic curves in the region of low water flow rate to operate in wider two-phase flow conditions.

Similarity Law of Air-Water Two-Phase Flow Performance of Centrifugal Pump

2007 ◽  
Author(s):  
Naoki Matsushita ◽  
Satoshi Watanabe ◽  
Kusuo Okuma ◽  
Tomomichi Hasui ◽  
Akinori Furukawa
Keyword(s):  
Centrifugal Pump ◽  
Rotational Speed ◽  
Flow Condition ◽  
Two Phase Flow ◽  
Operating Conditions ◽  
Phase Flow ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Blade Height ◽  
Similarity Law

Air-water two-phase flow performance of conventional centrifugal pumps causes the impermissible head deterioration even at an inlet void fraction less than about 10%. A tandem arrangement of double rotating cascades and higher blade outlet angle more than 90° only in outer rotating cascade has been proposed as a centrifugal pump impeller with high performance in air-water two-phase flow condition. To obtain further improvement of pump performances, a diffuser cascade is installed downstream of impeller outlet. In design of air-water two-phase flow centrifugal pump in various size and operating conditions as well as in single-phase flow, similarity law of pump performances is very useful. The similarity law of impeller diameter, blade height and rotational speed is investigated for the proposed impeller in the present paper. As the results, the similarity law of impeller diameter and rotational speed is certified experimentally even in two-phase flow condition. In addition, influences of blade height on air-water two-phase flow performances indicate a little difference from the similarity law. This difference is, then, discussed by using the results of static head on the shroud wall and air behaviors in the impellers.

Experimental Characterization of Two-Phase Flow Through Valves Applied to Liquid-Assisted Gas-Lift

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Renato P. Coutinho ◽  
Paulo J. Waltrich ◽  
Wesley C. Williams ◽  
Parviz Mehdizadeh ◽  
Stuart Scott ◽  
...  
Keyword(s):  
Water Flow ◽  
Two Phase Flow ◽  
Numerical Study ◽  
Water Flow Rate ◽  
Phase Flow ◽  
Experimental Characterization ◽  
Two Phase ◽  
Flow Through ◽  
Gas Lift

Abstract Liquid-assisted gas-lift (LAGL) is a recently developed concept to unload wells using a gas–liquid fluid mixture. The success deployment of the LAGL technology is related to the behavior of two-phase flow through gas-lift valves. For this reason, this work presents an experimental and numerical study on two-phase flow through orifice gas-lift valves used in liquid-assisted gas-lift unloading. To the knowledge of the authors, there is no investigation in the literature on experimental characterization of two-phase flow through gas-lift valves. Experimental data are presented for methane-water flow through gas-lift valves with different orifice port sizes: 12.7 and 17.5 mm. The experiments were performed for pressures ranging from 1.00 to 9.00 MPa, gas flow rates from 0 to 4.71 m3/h, and water flow rate from 0 to 0.68 m3/min. The experimental results are compared to numerical models published in the literature for two-phase flow through restrictions and to commercial multiphase flow simulators. It is observed that some models developed for two-phase flow through restrictions could successfully characterize two-phase flow thorough gas-lift valves with errors lower than 10%. However, it is first necessary to experimentally determine the discharge coefficient (CD) for each gas-lift valve. The commercial flow simulators showed a similar performance as the models available in the literature.

Analysis of Orifice Plate Differential Pressure Noise in Horizontal and Vertical Rising Gas-Water Two-Phase Flow

2010 ◽  
Author(s):  
Xianfa Li ◽  
Shuoping Zhong ◽  
Yanfei Sun
Keyword(s):  
Flow Rate ◽  
Two Phase Flow ◽  
Water Flow Rate ◽  
Differential Pressure ◽  
Orifice Plate ◽  
Vapor Flow ◽  
Phase Flow ◽  
Square Root ◽  
Two Phase ◽  
The Difference

It is an important achievement of modern techniques to determine the mass flow rate and the phase fraction of wet steam by measuring the orifice plate differential pressure noise. The orifice plate differential pressure noise of air-water two-phase flow in horizontal and vertical rising pipelines were analyzed. Kinds of calculation methods were tried to get the differential pressure noise. From the difference waveform of the differential pressure square root that the acquisition card got and the mean square root of the sample that got before, the first in first out (FIFO) principle was used to get the differential pressure noise. Result shows that the differential pressure noise has different level at different vapor flow rate with the same water flow rate, conclusions show that the two-parameter measurement by using orifice plate differential pressure noise may be possibly used in vertical rising gas-water two phase flow.

Air/Water Two-Phase Flow Performance of Contra-Rotating Axial Flow Pump and Rotational Speed Control of Rear Rotor

2005 ◽  
Author(s):  
Toru Shigemitsu ◽  
Akinori Furukawa ◽  
Satoshi Watanabe ◽  
Kusuo Okuma
Keyword(s):  
Flow Rate ◽  
Rotational Speed ◽  
Two Phase Flow ◽  
Axial Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Rate Range ◽  
Flow Rate Range ◽  
Axial Flow Pump ◽  
Flow Pump

An application of contra-rotating rotors, consisting of front and rear rotors rotating in the opposite direction from each other, has been proposed against a demand for developing a higher specific speed axial flow pump with a more compact structure, higher efficiency and higher cavitation performance. As axial flow pumps are used for standby operations of air-lock and air/water mixing discharge to prevent floods, air/water two-phase flow performance of the contra-rotating pump has to be also investigated. In the present paper, therefore, experimental results on air/water two-phase flow performance of a test pump with contra-rotating rotors are shown and compared with those of a conventional axial flow pump, consisting of a front rotor and a rear stator. Even under two-phase flow conditions head characteristic curve of the contra-rotating type has a more strongly negative slope than that of the conventional type. The contra-rotating type maintains higher head and higher efficiency even in the low flow rate range and vice versa in the high flow rate range. This result will be discussed by considering the change of outlet flow from front rotor due to two-phase flow with the help of observed air behavior in the rotors. Then effects of changes of rear rotor rotational speed different from front rotor speed, which is an advantage of the contra-rotating axial flow pump, on two-phase flow performance are examined. Under the condition of constant ratio of air to water flow rates, the head rise of the rear rotor linearly increases with rear rotor rotational speed. Air/water two-phase flow performance of the contra-rotating axial flow pump can be improved by this control procedure for the rear rotor rotational speed.

scholarly journals Ligament and Droplet Generation by Oil Film on a Rotating Disk

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Hengchao Sun ◽  
Guoding Chen ◽  
Li’na Wang ◽  
Fei Wang
Keyword(s):  
Film Thickness ◽  
Flow Rate ◽  
Rotational Speed ◽  
Two Phase Flow ◽  
Rotating Disk ◽  
Droplet Generation ◽  
Phase Flow ◽  
Two Phase ◽  
Disk Radius ◽  
Oil Film

The lubrication and heat transfer designs of bearing chamber depend on an understanding of oil/air two-phase flow. As initial and boundary conditions, the characteristics of ligament and droplet generation by oil film on rotating parts have significant influence on the feasibility of oil/air two-phase flow analysis. An integrated model to predict the oil film flow, ligament number, and droplet Sauter mean diameter (SMD) of a rotating disk, which is an abstraction of the droplet generation sources in a bearing chamber, is developed based on the oil film force balance analysis and wave theory. The oil film thickness and velocity, ligaments number, and droplet SMD are calculated as functions of the rotating disk radius, rotational speed and oil volume flow rate and oil properties. The theoretical results show that the oil film thickness and SMD are decreased with an increasing rotational speed, while the radial, transverse velocities, and ligament number are increased. The oil film thickness, radial velocity, and SMD are increased with an increasing oil flow rate, but the transverse velocity and ligament number are decreased. A test facility is built for the investigation into the ligament number of a rotating disk, and the measurement of ligament number is carried out by means of a high speed photography.

Experimental Study on the Void Fraction of Siphon Breaking Process

2017 ◽  
Author(s):  
Lei Xing-lin ◽  
Huang Shan-fan ◽  
Guo Zhong-xiao ◽  
Guo Xiao-yu
Keyword(s):  
Void Fraction ◽  
Flow Rate ◽  
Nuclear Power ◽  
Two Phase Flow ◽  
Water Flow Rate ◽  
Experimental Results ◽  
Physical Parameters ◽  
Phase Identification ◽  
Phase Flow ◽  
Two Phase

As a safety device to alleviate the loss of reactor coolant, the siphon breaking system is widely used in nuclear power plant. Researchers are very interested in this technique for its “passive” characteristic. Vertical downward air-water two-phase flow is encountered in the siphon breaking process. Previous researches have been more focused on some physical parameters, such as water flow rate, air flow rate, pressure drop and the undershooting height. Void fraction, as a key parameter in multiphase flow, should be studied in the siphon breaking phenomenon. Therefore, a needle-contact capacitance probe is used for flow-phase identification and a single-wire capacitance for obtaining the average value of gas distribution along the straight line. Experimental results show that the flow pattern during the vertical downward air-water two-phase flow is mostly annular flow. With the gas entering the pipeline, void fraction profile against time can be divided into three stages. The slope in the first stage is similar to that in the third. However, the slope slows down in the middle stage. The experimental results also show that the real duration time to break the siphon flow is as short as about 6 s. The void fraction at the end of the siphon breaking process is about 0.38. During this stage, a large amount of gas is sucked into the downcomer and little water is inhaled. The gas phase results in a convergent effect, where the air intake is the direct and fundamental reason of siphon breaking.

Slip Factor for Centrifugal Impellers Under Single and Two-Phase Flow Conditions

2004 ◽  
Vol 127 (2) ◽  
pp. 317-321 ◽  
Author(s):  
José A. Caridad ◽  
Frank Kenyery
Keyword(s):  
Fluid Dynamics ◽  
Centrifugal Pump ◽  
Flow Rate ◽  
Prediction Models ◽  
Two Phase Flow ◽  
Specific Capacity ◽  
Phase Flow ◽  
Two Phase ◽  
Slip Factor ◽  
Pump Flow Rate

Throughout the history of turbomachines investigators have tried to develop reliable methods for prediction of centrifugal pump behavior. Among the parameters available to estimate the performance of this kind of machine is the slip factor. In spite of being regarded as a variable of great significance in the analysis of turbomachinery, there seem to be a misconception regarding its concept and application. Indeed, empirical correlations have been widely used to estimate the slip factor, even in the case of two-phase flow applications, where it has not been investigated. Moreover, these correlations provide a constant value of the slip factor for a given impeller only at the best efficiency point, which is an important restriction to the pump performance prediction, considering that slip factor varies with the pump flow rate. In this study, three-dimensional computational fluid dynamics simulations were carried out on an impeller of known geometry (NS=1960) from which values of slip factor were calculated for both single- and two-phase flow (water and water-air). These results include curves of the slip factor as a function of the specific capacity and the gas-void fraction. Additionally, results for the slip factor in the case of single-phase flow (water) are given for various centrifugal impellers (NS=1157, 1447, 1612, and 3513) in order to illustrate the influence of the flow rate on this parameter. Finally, based on the numerical results, a methodology for prediction of the pump head is presented. Excellent agreement with experimental results has been found. This paper attempts to contribute to a better understanding of the fluid dynamics within centrifugal pump impellers and to shed more light on the path that prediction models should follow in the future.

Evaluation of Liquid-Gas Two-Phase Flow Pressure Drop Signatures in Proton Exchange Membrane (PEM) Fuel Cell Flow Channels

2018 ◽  
Author(s):  
Mehdi Mortazavi ◽  
Jingru Benner ◽  
Anthony Santamaria
Keyword(s):  
Fuel Cell ◽  
Pressure Drop ◽  
Water Flow ◽  
Flow Rate ◽  
Two Phase Flow ◽  
Pem Fuel Cell ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Rates ◽  
Flow Pressure

In this study, liquid-gas two-phase flow pressure drops were measured in an ex-situ PEM fuel cell test section. Pressure drop signatures were studied for three nominal air flow rates and different water flow rates within a flow channel. The pressure drop signatures showed an increasing trend at the beginning of the experiments which were followed by a drop to lower values before reaching uniform patterns. It was observed that as the water flow rate increased, the time interval at which pressure signatures reached uniform patterns decreased. In addition, a qualitative comparison with Mishima-Hibiki model [13] revealed that this two-phase flow pressure drop model showed the best prediction capability for the medium air flow rate used in this study, ∼300mℓ/min inflow channel, corresponding to ∼220 Reynolds number.

Sign in / Sign up

Export Citation Format

Share Document