Measurement of properties of a dispersed phase in air-water multiphase flow using novel four-sensor probe and orthogonal high speed cameras

Measurement of the volumetric flow rate of each of the flowing components in multiphase flow is required to be monitored in production logging applications. Thus, an increasing level of interest has been shown by researchers worldwide in making flow rate measurements in multiphase flow accurate to a high level. A new generation of tomographic instruments, which enable the measurement of the instantaneous local velocity vector and the instantaneous local volume fraction of the dispersed phase, are now being introduced. However validation and calibration of such instruments is very important to enable quality assured measurements. This paper introduces a camera based calibration system for local 4-sensor probes which can be used to quantify the bubble-probe interaction and the accuracy with which the probe can measure velocity vector, for air bubbles in water and oil droplets in wate

Three-body constrained bosons in double-well optical lattice

We analyse the ground-state properties of three-body constrained bosons in a one dimensional optical lattice with staggered hoppings analogous to the double well optical lattice. By considering attractive and repulsive on-site interactions between the bosons, we obtain the phase diagram which exhibits various quantum phases. Due to the double-well geometry and three-body constraint several gapped phases such as the Mott insulators and dimer/bond-order phases emerge at commensurate densities in the repulsive interaction regime. Attractive interaction leads to the pair formation which leads to the pair bond order phase at unit filling which resembles the valence-bond solid phase of composite bosonic pairs. At incommensurate densities we see the signatures of the gapless pair superfluid phase.Comment: 10 pages, 19 figure

Advanced Techniques for Surface Engineering of Industrial Materials

This paper deals with the various advanced surface modification techniques. It has been pointed out that each techniques has its own merits and demerits and a proper choice has to made depending upon the properties and quality expected from for specific applications

Condition Based Monitoring of Vertical Axis Wind Turbines using Computational Fluid Dynamics

Scarcity of fossil fuels and a rapid escalation in the fuel prices around the world recently has lead the search for alternative energy sources. Out of the available energy sources, wind is being considered as the prime next generation energy source. The fundamental principle of wind turbines is to convert the wind energy into first mechanical and then into electrical form. The relatively simple operation of such turbines has stirred the researchers to come up with innovative designs for global acceptance and to make these turbines commercially viable. Furthermore, the maintenance of wind turbines has long been a topic of interest. On-line health monitoring of wind turbines is essential to maintain continuous operation of wind turbines. The present work focuses on the difference in the outputs of a vertical axis wind turbine (VAWT) under different operational conditions. A Computational Fluid Dynamics (CFD) technique has been used to monitor various blade conditions of a VAWT. The results indicate that there is significant degradation in the performance output of wind turbines as the number of blades broken or missing from the VAWT increases. The study predicts the faults in the blades of VAWTs by monitoring its output

Flow diagnosis in a domestic radiator

In UK, domestic heating contributes to about 40% of annual energy consumption. Effective and efficient heating systems are essential to drive the cost of heating down. Although there are several types of heating systems, radiators are the most popular heat emitters. Head loss in a radiator depends on various design parameters based on fluid flow path conditions and design of the radiator. In the present study, a computational fluid dynamics (CFD) code has been used to analyse flow distribution within a domestic radiator. For this study a radiator with dimensions of 300mm by 600mm with 18 columns has been considered. The study has been carried out on a radiator with BBOE and BTOE configuration at various flow rates. In this paper results are presented from a series of analysis in which flow structure within the radiator has been diagnosed

Effect of the shape of connecting pipes on the performance output of a closed-loop hot water solar Thermo-syphon

In order to conserve the environment from pollution, which is caused by the use of the fossil fuels, numerous research works have been carried out in renewable energy area to minimize the dependency on the fossil fuels. There are several energy sources naturally available, and solar energy is considered to be the best amongst them. Therefore it became a motivating area for the researchers in recent years. Thermo-syphon is one of many devices that use solar energy for power generation. Thermo-syphon converts solar energy into internal energy of the working fluid; mainly water. In this work, a computational fluid dynamics (CFD) code has been used to analyse the natural convection phenomenon in a thermo-syphon. The thermo-syphon model consist of steel pipes with an internal diameter of 25mm, along with a condenser having diameter equal to five times the pipe’s diameter, has been considered. The study has been carried out under no-loading conditions, for two thermo-syphon models comprising of straight and helical shaped pipes of 10, 20 and 30. A practical solar heat flux of 500W/m2 has been applied on the pipes. The numerical results depict that the working fluid within the condenser, in case of helical pipes, gains higher temperature as compared to the straight pipes. Furthermore, increase in the number of helical pipes has negligibly small effect on the temperature of the fluid within the condenser, and hence on the performance output of the thermo-syphon

Flow diagnostics

The measurement of flow properties within fluid handling systems is of utmost importance for efficient operation and control of such systems. For single phase flow systems, extensive research has been carried out world over to diagnose the flow properties both globally and locally. Considerable advancements are being made to perfect these technologies. For multiphase flows there is still a lot of scope for technological development that needs to take place to diagnose the flow conditions accurately efficiently and effectively. In this present paper two methods are described that can be used effectively for measurement of flow properties in solid-liquid flows and gas-liquid flows. One of the methods relies on isokinetic sampling used in conjunction with impact probe for the determination of solid distribution and solid velocity in solid-liquid flows through a pipeline. The other method relies on electrical resistance method to calculate local flow velocity corresponding to the dispersed phase as well as volume fraction and interfacial area concentration

Visual estimation of blood loss versus quantification of blood loss after vaginal birth using an innovative drape: a prospective study

Background: This study was done to compare the accuracy of visual estimation of blood loss (EBL) and quantitative assessment of blood loss (QBL, sum of volumetric and gravimetric assessment) against a reference standard i.e. calculated QBL (C-QBL) and also with each other after vaginal birth.Methods: Prospective observational cohort study conducted at Pt. JNM medical College Raipur, Chhattisgarh, India and involved 101 low risk women after vaginal birth. Women were allocated alternately to EBL or QBL group (volumetric component of measured blood loss was done with an innovative low cost drape prepared with a plastic apron at the point of care. Gravimetric component was measured by weight difference of the mops and pads before and after use). C-QBL was calculated for each case with a standard formula. Main outcome measure was comparing the correlation coefficient of EBL and QBL each with C-QBL.Results: The mean blood loss in 51 women of EBL group and 50 women of QBL group was 275.29 ml and 380 ml respectively. Pearson’s correlation coefficient (r) of EBL with C-QBL was 0.4984 (weak correlation) compared to that of QBL with C-QBL (r=0.9093, strong positive correlation). The error of underestimation by EBL compared to QBL was 28% (mean=104.71 ml p500 ml by EBL method was 5 (95% CI .605-41.3).Conclusions: Visual EBL should be replaced with QBL for measurement of postpartum blood loss. Using innovative under-buttock low cost drape greatly helps in routine QBL