EXPERIMENTAL STUDY OF BAR FORMATION IN SAND BED CHANNEL

2016 ◽  
Vol 78 (5-3) ◽  
Author(s):  
Duratul Ain Tholibon ◽  
Junaidah Ariffin ◽  
Jazuri Abdullah ◽  
Juliana Idrus
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Experimental Work ◽  
Large Scale ◽  
Sediment Supply ◽  
Hydraulic Characteristics ◽  
Flow Rates ◽  
Physical Mechanisms ◽  
Bed Slope ◽  
Bar Formation

A large number of studies both theoretical and experimental have been devoted to understand the physical mechanisms underlying the bar formation. This can be investigated by carrying out an experimental work in an erodible sand bed channel using a large-scale physical river model. The study included the various hydraulic characteristics with steady flow rates and sediment supply. An experimental work consists of four matrices of flow rate and channel width with other variables namely grains size and bed slope were kept constant. Details of bar profile development that generated using Surfer, a software used for 3D elevation plots are included.

Model-Based Analysis of Transient Behavior of Large Scale CFB Boilers

2003 ◽  
Author(s):  
Ari Kettunen ◽  
Timo Hyppa¨nen ◽  
Ari-Pekka Kirkinen ◽  
Esa Maikkola
Keyword(s):  
Flow Rate ◽  
Large Scale ◽  
Air Flow ◽  
Model Parameters ◽  
Air Flow Rate ◽  
Process Data ◽  
Cfb Boiler ◽  
Flow Rates ◽  
Load Change ◽  
Secondary Air

The main objective of this study was to investigate the load change capability and effect of the individual control variables, such as fuel, primary air and secondary air flow rates, on the dynamics of large-scale CFB boilers. The dynamics of the CFB process were examined by dynamic process tests and by simulation studies. A multi-faceted set of transient process tests were performed at a commercial 235 MWe CFB unit. Fuel reactivity and interaction between gas flow rates, solid concentration profiles and heat transfer were studied by step changes of the following controllable variables: fuel feed rate, primary air flow rate, secondary air flow rate and primary to secondary air flow ratio. Load change performance was tested using two different types of tests: open and closed loop load changes. A tailored dynamic simulator for the CFB boiler was built and fine-tuned by determining the model parameters and by validating the models of each process component against measured process data of the transient test program. The know-how about the boiler dynamics obtained from the model analysis and the developed CFB simulator were utilized in designing the control systems of three new 262 MWe CFB units, which are now under construction. Further, the simulator was applied for the control system development and transient analysis of the supercritical OTU CFB boiler.

Experimental Study of Various Porosity of Fractal Flow Conditioner for Orifice Plate Flowmeters

2014 ◽  
Vol 699 ◽  
pp. 915-920 ◽  
Author(s):  
Bukhari Manshoor ◽  
Mohd Fahmi Othman ◽  
Izzuddin Zaman ◽  
Zamani Ngali ◽  
Amir Khalid
Keyword(s):  
Experimental Study ◽  
Pressure Drop ◽  
Mass Flow Rate ◽  
Flow Rate ◽  
Experimental Work ◽  
Discharge Coefficient ◽  
Orifice Plate ◽  
Rate Data ◽  
Plant Industry ◽  
Measure Flow Rate

The plant industry is required to measure flow rate more accurately to meet plant operation and cost accounting objectives. The opposing concern of improving flow meter accuracy is resolved by using flow conditioners. The distance of implementation of flow conditioner upstream of the orifice plate flowmeter is also need to be addressed. Hence, in present study, an analysis of the porosity of fractal flow conditioner towards orifice plate flowmeter’s accuracy and the best distance of fractal flow conditioner upstream of the orifice plate flowmeter was determined. In an experimental work, a different porosity of the fractal flow conditioners were installed with different distance upstream of the orifice plate in conjunction with the different disturbances to assess the effects of these devices on the measurement of the mass flow rate. Data gained for all the plates showed that there is increment of pressure drop and change in discharge coefficient of the orifice with lower β value of fractal flow conditioner. Good comparisons with the previous experimental work demonstrate the fractal flow conditioner can preserve the accuracy of metering up to the level required in the standards.

Effect of nozzle angle, turbine inlets and mass flow rate on the performance of a bladeless turbine

2019 ◽  
Vol 234 (8) ◽  
pp. 1101-1107
Author(s):  
Muhammad Ali Kamran ◽  
Shahryar Manzoor
Keyword(s):  
Experimental Study ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Working Fluid ◽  
Operating Parameters ◽  
Lower Mass ◽  
Flow Rates ◽  
Significant Parameter ◽  
Mass Flow Rates

A comprehensive experimental study on the effects of different operating parameters on the efficiency of tesla turbine is reported. A bladeless turbine with nine discs and up to four turbine inlets was used, with water as the working fluid. The parameters investigated are the nozzle angle, number of turbine inlets and mass flow rates. Contrary to earlier studies, an effort was made to determine the performance under varying loading conditions, and hence identify the complete performance characteristics. The study revealed that efficiency of the turbine increases at lower nozzle angles and higher number of turbine inlets. It was observed that the nozzle angle becomes a significant parameter when the number of turbine inlets is increased. Efficiencies up to 78% were achieved when the working fluid entered the turbine through two nozzles at an angle of 7°. It was also noted that the turbine is most efficient at the designed mass flow rate, and the efficiency reduces appreciably if lower mass flow rates are fed to the turbine. The results obtained are an important contribution to the available knowledge and can be used as design references for further studies.

Nozzle Passage Endwall Effectiveness Values with Various Combustor Coolant Flow Rates - Part 1: Flowfield Velocity and Coolant Concentration Measurements

2021 ◽  
pp. 1-53
Author(s):  
Kedar P. Nawathe ◽  
Rui Zhu ◽  
Enci Lin ◽  
Yong Kim ◽  
Terrence Simon
Keyword(s):  
Flow Rate ◽  
Large Scale ◽  
Three Dimensional ◽  
Reynolds Numbers ◽  
Coolant Flow ◽  
Surface Cooling ◽  
Cooling Effectiveness ◽  
Flow Rates ◽  
Flow Physics ◽  
High Level

Abstract The stators of the first stage of a gas turbine are exposed to severe temperatures. The coolant streams introduced to prevent the stators from thermal damage further complicate the highly three-dimensional vane passage flow. Recent results have shown that the coolant streams injected for cooling the combustor also influence the flow physics and the cooling effectiveness in the first-stage stator vanes passage. However, the effects of changing the mass flow rate of these combustor coolant streams on the passage flowfield have not been studied. As understanding the coolant transport is necessary for analyzing changes in cooling effectiveness in the vane passage, detailed aerodynamic and thermal measurements along the whole vane passage are required. This two-part paper presents such measurements taken for a variety of combustor coolant and endwall film coolant flow rates. The experiments were conducted in a low-Mach-number facility with engine-representative Reynolds numbers and large-scale high-level turbulence. The objective of the first part is to describe the flow that influences endwall and vane surface cooling effectiveness distributions, which are presented in the second part. The measurements show changes in the passage flowfield due to changes in both combustor coolant and endwall film coolant flow rates. Overall, the flow-physics remains largely unaffected by changes in coolant flow rates except in the endwall-vane surfaces region where the combustor coolant flow rate dominates changes in coolant transport. This is shown to have a high impact on endwall and vane surface cooling.

scholarly journals Hydraulic characteristic of collagen

2016 ◽  
Vol 33 (No. 5) ◽  
pp. 479-485 ◽  
Author(s):  
R. Žitný ◽  
A. Landfeld ◽  
J. Skočilas ◽  
J. Stancl ◽  
V. Flegl ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Limited Range ◽  
Hydraulic Characteristic ◽  
Hydraulic Characteristics ◽  
Flow Rates ◽  
Transient Flows ◽  
Wide Range ◽  
On Line ◽  
Collagenous Material

Hydraulic characteristic of collagen. Czech J. Food Sci., 33: 479–485. The hysteresis of a hydraulic characteristic while pumping an aqueous solution of collagen through a pipe at gradually increasing and decreasing flow rates (hysteresis means that the pressure drop curve during increased flow rate is above the pressure drop during decreasing flow rate) was observed. The problem was initiated by industry and by demand for an on-line recording of rheological properties of collagenous material used for extrusion of collagen casings. The Herschel-Bulkley rheological model was capable to describe rheograms in a wide range of deformation rates; however it was not able to describe and explain the hysteresis. As a possible reason thixotropic properties were identified and the hydraulic characteristic was calculated using a thixotropic generalisation of the Herschel-Bulkley model. The developed 1D numerical model can be applied for on-line modelling of transient flows of incompressible thixotropic food materials (startup flow) and at a limited range of flow rates it is also capable to describe the hysteresis of hydraulic characteristics.

The effects of oyygen on acclimatized men at high altitude

1954 ◽  
Vol 143 (910) ◽  
pp. 14-17 ◽  
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Experimental Work ◽  
Lung Ventilation ◽  
Open Circuit ◽  
Work Rate ◽  
Flow Rates ◽  
The Times ◽  
Extra Weight ◽  
Work Done

Knowledge of the effects of oxygen on acclimatized men at altitudes above 22 000 ft. depends entirely on the experience of mountaineers on Everest. Experimental data are, however, available up to 20000 ft. from work done on the Cho Oyu expedition in 1952, and up to 21000 ft. from work done on Everest the following year. The results of this experimental work are presented here, followed by the empirical findings of the Everest climbers in 1953. On Cho Oyu in 1952 we studied the effect of breathing different concentrations of oxygen on work rate and lung ventilation. Work rates were compared by timing men ascending a 300 ft. snow slope on a prepared track. Runs were done using open circuit equipment at flow rates of 4 and 10 l. O 2 /min. The equipment, which was carried on the back, weighed 22 lb. Control runs were done ( a ) breathing air and not carrying the equipment, ( b ) carrying the equipment with the supply of oxygen turned off. The effect of the extra weight of the equipment was to increase the times by approximately 25%. The effect of breathing extra oxygen was to shorten the times by approximately 10 %. The 10 l. flow rate was somewhat more effective than the 4 l. flow rate but the differences were small.

scholarly journals Experimental study of in-situ W/O emulsification during the injection of MgSO4 and Na2CO3 solutions in a glass micromodel

2020 ◽  
Vol 75 ◽  
pp. 87
Author(s):  
Sepideh Palizdan ◽  
Hossein Doryani ◽  
Masoud Riazi ◽  
Mohammad Reza Malayeri
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Oil Recovery ◽  
Deionized Water ◽  
Water Flooding ◽  
Flow Rates ◽  
Glass Micromodel ◽  
The Impact ◽  
Emulsification Process

In-situ emulsification of injected brines of various types is gaining increased attention for the purpose of enhanced oil recovery. The present experimental study aims at evaluating the impact of injecting various solutions of Na2CO3 and MgSO4 at different flow rates resembling those in the reservoir and near wellbore using a glass micromodel with different permeability regions. Emulsification process was visualized through the injection of deionized water and different brines at different flow rates. The experimental results showed that the extent of emulsions produced in the vicinity of the micromodel exit was profoundly higher than those at the entrance of the micromodel. The injection of Na2CO3 brine after deionized water caused the impact of emulsification process more efficiently for attaining higher oil recovery than that for the MgSO4 brine. For instance, the injection of MgSO4 solution after water flooding increased oil recovery only up to 1%, while the equivalent figure for Na2CO3 was 28%. It was also found that lower flow rate of injection would cause the displacement front to be broadened since the injected fluid had more time to interact with the oil phase. Finally, lower injection flow rate reduced the viscous force of the displacing fluid which led to lesser occurrence of viscous fingering phenomenon.

scholarly journals Importance of viscosity contrast for the motion of erythrocytes in microcapillaries

2021 ◽  
Author(s):  
Anil K. Dasanna ◽  
Johannes Mauer ◽  
Gerhard Gompper ◽  
Dmitry A. Fedosov
Keyword(s):  
Flow Rate ◽  
Blood Cells ◽  
Flow Resistance ◽  
Tube Flow ◽  
Membrane Tension ◽  
Flow Rates ◽  
Physical Mechanisms ◽  
State Diagrams ◽  
Viscosity Contrast

ABSTRACTThe dynamics and deformation of red blood cells (RBCs) in microcirculation affect the flow resistance and transport properties of whole blood. One of the key properties that can alter RBC dynamics in flow is the contrast λ (or ratio) of viscosities between RBC cytosol and blood plasma. Here, we study the dependence of RBC shape and dynamics on the viscosity contrast in tube flow, using mesoscopic hydrodynamics simulations. State diagrams of different RBC dynamical states, including tumbling cells, parachutes, and tank-treading slippers, are constructed for various viscosity contrasts and wide ranges of flow rates and tube diameters (or RBC confinements). Despite similarities in the classification of RBC behavior for different viscosity contrasts, there are notable differences in the corresponding state diagrams. In particular, the region of parachutes is significantly larger for λ = 1 in comparison to λ = 5. Furthermore, the viscosity contrast strongly affects the tumbling-to-slipper transition, thus modifying the regions of occurrence of these states as a function of flow rate and RBC confinement. Also, an increase in cytosol viscosity leads to a reduction in membrane tension induced by flow stresses. Physical mechanisms that determine these differences in RBC dynamical states as a function of λ are discussed.

scholarly journals ŠILUMNEŠIO DEBITO ĮTAKOS FAZINIO VIRSMO MEDŽIAGOS VEIKIMUI TYRIMAS / INVESTIGATION OF THE INFLUENCE OF MASS FLOW RATE ON PHASE CHANGE MATERIAL BEHAVIOUR

2019 ◽  
Vol 11 (0) ◽  
pp. 1-5 ◽  
Author(s):  
Saulius Pakalka ◽  
Kęstutis Valančius ◽  
Matas Damonskis
Keyword(s):  
Experimental Study ◽  
Phase Change ◽  
Mass Flow Rate ◽  
Phase Change Material ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Transfer Fluid ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Change Material

The paper presents an experimental study of the influence of heat transfer fluid (HTF) mass flow rate on phase change materials (PCM) behaviour. The experimental study was performed on a specially designed test bench. Research object – PCM based thermal energy storage unit which consists of a stainless steel tank with dual circuit tube-fin copper heat exchanger. The tank (storage volume) was filled with phase change material RT82. The experiment was carried out using three different mass flow rates of HTF: high – 0.25 kg/s, medium – 0.125 kg/s, low – 0.05 kg/s. The analysis showed that in the case of high and medium mass flow rates the melting/solidification process highly depends on the temperature of inlet HTF. Influence of mass flow rate is higher in the case of low mass flow rate.

Experimental Study on Planar Unidirectional Permeability of Glass Fiber Preforms at Constant Flow Rate

2010 ◽  
Vol 154-155 ◽  
pp. 494-497
Author(s):  
Shi Lin Yan ◽  
Fei Yan ◽  
Zhong Qi Qiu
Keyword(s):  
Experimental Study ◽  
Flow Rate ◽  
Resin Flow ◽  
Constant Flow ◽  
Flow Rates ◽  
One Dimensional ◽  
Constant Flow Rate ◽  
Transfer Molding ◽  
The One ◽  
Fiber Preforms

During the resin flow of Resin Transfer Molding, the permeability of fiber performs is an important parameter, which reflects the interaction between the resin and fiber. In this paper the Darcy’s law was used as the fundamentals to determine the permeability of fiber performs, an experiment installation was designed, and do some experimental study on the one-dimensional permeability of resin in the multilayer fibrous plaids at a constant flow rate. The installation was designed base on condition of different flow rates and different fiber volumes (or porosity), and compared the results of the permeability of different flow rates. Then analyzed the results, and some content conclusions were obtained.

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