A LabVIEW-based PI controller for controlling CE 105 coupled Tank System

In this paper, use of Proportional-Integral (PI) controller to monitor and control liquid level in an interconnected CE 105 model coupled tank is investigated. To achieve a system which can instantaneously and accurately control the liquid level in a coupled tank, two different PI controllers have been tested. The LabVIEW library for the PI controller is used to measure liquid levels in the coupled tank. The PI SubVI already exists in the LabVIEW library that gives reasonable performance but to get a better system performance and monitor the liquid levels more accurately another SubVI is derived from the PI controller mathematical equations. The practical results and the system performance of the second SubVI show a faster response and more accurate instantaneous data which minimises the error in the measurements to ±1 mm. Furthermore, the robustness of the controller to change in the system’s parameters is also investigated and established

Using Computer Technology Tools to Improve the Teaching-Learning Process in Technical and Vocational Education: Mechanical Engineering Subject Area

This paper discusses the integration of computer assisted instructions (CAI) with traditional class room teaching. It describes a teaching method to bring real-world of industrial work into the classroom that underscores the need to learn fundamental principles while adding excitement and relevance to the experience. This paper presents results of a case study undertaken to understand the effect of computer assisted teaching methodology on learning effectiveness in classroom environment. The effects of computer assisted instructions on different levels of cognition of individual learners have also been evaluated. The computer aided drawing (CAD), computer aided manufacturing (CAM) and computer numerical control (CNC) courses at the Bahrain institute are an integral part of this attempt. These courses emphasize the development of a 3-D geometric computer model and application of this digital database to all phases of the design process. The students make freehand sketches, build computer models, mate assemblies of parts, perform various analysis, create kinematics simulations, generate final design drawings, import engineering drawing as DXF file, generate NC file to build rapid prototypes as shown in the table 1 below. Keywords: Computer Technology, C.N.C and AutoCad Softwar

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

How has the Indian Corporate Sector Responded to Two Decades of Economic Reforms in India? An Exploration of Patterns and Trends

In the context of various policy initiatives made during the last two decades to reform the Indian economy in general and corporate sector in particular, the present paper attempts to assess how the firms have responded to these policy measures and the resultant changes in the business conditions in a long run perspective. The paper finds that although the rate of growth of the Indian industry sector has not accelerated following economic reforms probably due to slow growth in agriculture and industrial productivity, investment in general and FDI in particular have shown considerable increase. Increase in competitive pressures during this period has forced the firms to adopt a variety of strategies. While reliance on mergers and acquisitions (M&A) has increased to restructure business and grow, the role of embodied and disembodied technology purchase has declined with firms relying somewhat more on in-house R&D. On the other hand, although strategies of building marketing and distribution related complementary assets continue to dominate the strategy of product differentiation, their role in a relative sense seems to have declined as these expenses as a proportion of sales show a declining trend. However, the emerging competitive pressures have raised the importance of sub-contracting/ outsourcing manufacturing, reducing the degrees of vertical integration. Interestingly, while cost-efficiencies do not show improvements, export orientation has increased across the industries significantly signaling enhanced global competitiveness of Indian firms, although imports have risen faster than exports. Overall, the observed trends of corporate response to economic reforms are interesting, but one need to systematically explore how M&A led consolidation and flows of FDI are linked to the adoption of various non-price strategies relating to technology and product differentiation. As economic reform deepens and competitive pressures build up, an analysis of these interactions would provide useful insights for understanding corporate behaviour and for making policy choices.

Numerical Investigations on the Transient Performance of a Centrifugal Pump

Centrifugal pumps are an integral part of plants used in process industries. The flow structure within a centrifugal pump is very complex due to the interaction between the rotating impeller and the geometric features around it. In the present study, numerical investigations on a centrifugal pump have been carried out using a Computational Fluid Dynamics (CFD) based solver. This study employs finite volume technique in order to analyse the influence of variations in the rotational speed of the pump on its head. The instantaneous behaviour of a centrifugal pump with varying rotational speeds is studied using the Sliding Mesh technique. The performance parameters of a centrifugal pump have been predicted using numerical simulations. The results indicate that as the rotational speed of the centrifugal pump decreases, the head developed by the pump also decreases, where the effects of varying rotational speeds are dominant in the volute region. Furthermore, the complex interaction between the impeller blades and the tongue region has been analysed in the present study

Numerical Investigations on the Performance Degradation of a Vertical Axis Wind Turbine Operating in Dusty Environment

Rapid increase in global energy requirements has resulted in considerable attention towards energy generation from the renewable energy sources. In order to meet renewable energy targets, harnessing energy from all available resources including those from urban environment is required. Vertical Axis Wind Turbines (VAWTs) are seen as a potential way of utilising distributed wind energy sources. Most of the research on the wind turbines constitutes performance analysis and optimisation of VAWTs, in a clean environment, using steady state approximations where the transient effects are not considered. Operations in dusty environments (such as in desserts) may change the nature of the flow field around the VAWT which could decrease its life cycle. This study is an attempt to use Computational Fluid Dynamic’s based techniques to study and analyse the performance of a wind turbine under dusty environment. For this purpose, a novel modelling technique, known as Discrete Phase Modelling (DPM), has been used in the present study to introduce dust particles in the vicinity of a VAWT. The predicted results show that the instantaneous torque output of the VAWT decreases significantly in dusty environment. This abrupt change in the instantaneous torque output of the turbine may give rise to highly transient loads on the turbine’s structure which may induce heavy stresses on the turbine, leading to structural failure

Computational Fluid Dynamics based Flow Diagnostics in Hydraulic Capsule Pipeline Bends

Hydraulic Capsule Pipelines (HCPs) are the third generation of pipelines that are based on the transport of hollow spherical, or cylindrical, capsules by the force exerted on them from the carrier fluid, which is water. These hollow capsules can be filled with a variety of cargo goods, such as minerals, jewellery etc. The hydrodynamics of this transport phenomena is quite complex, and researchers around the globe have been trying to analyse the hydrodynamics of such systems. However, most of these studies are based on experimental investigations, which can provide reasonably accurate results for the pressure drop etc. across the pipeline. However, the flow structure within HCPs cannot be easily mapped using experimental facilities. Furthermore, in case of pipe bends, the difficulty level increases exponentially due to a constant curvature in the geometry of the pipeline, and hence mounting the flow measuring instruments can be very challenging. The present study makes use of the advanced Computational Fluid Dynamics (CFD) based solvers, with powerful computing services, in order to analyse the flow structure within HCP bends. It is expected that this information can provide valuable information to the HCP designers, not only to calculate pressure drop across HCP bends, but in order to select the correct size etc. bends for the pipeline

Numerical Investigations on Vortical Structures in the Near Tongue Region of a Centrifugal Pump during Transient Operation

Centrifugal pumps are considered to be an integral part of process industries around the world. The flow structure within centrifugal pumps is very complex due to the interaction between the rotating impeller and the geometric features around it, such as tongue. Researchers have been analysing the effects of the interactions between impeller blades and the tongue, however, most of these studies are based on steady-state approximations where the impeller blades are modelled using frozen-rotor approach which leads to discrepancies in the predicted flow fields. In the present study, fully transient numerical investigations, on the generation and dissipation of vortical structures in the vicinity of the tongue region, have been carried out using a commercial Computational Fluid Dynamics (CFD) based solver. The instantaneous behaviour of a centrifugal pump is studied using the Sliding Mesh technique. Simulations have been carried out on both a constant rotating speed and under decelerating conditions. The second invariant of the velocity gradient tensor i.e. Q-criterion, has been employed to identify the generation and dissipation of vortical structures near the tongue region of the pump. The results indicate that the Q-criterion is fairly non-uniform downstream the tongue region due to the complex interaction between the impeller blades and the tongue. Furthermore, it has been observed that as the rotational speed of the centrifugal pump decreases, the Q-criterion in the near tongue region remains constant. The generation, expansion and subsequent mixing of two distinct vortical structures have been noticed downstream the tongue (within the volute), whereby the strength of these structures has been observed to be decreasing as the distance from the tongue increases

Behavior of a CI Engine Running by Biodiesel under Transient Conditions

The emission characteristics of compression ignition (CI) engines running on biodiesel during transient operating conditions, which is the most usual case in urban and extra-urban transportation, have rarely been investigated. In the present study an experimental investigation on emission characteristics of a CI engine has been carried out both under steady state and transient operating conditions. The experimental work has been carried out on CI engine, which is integrated with transient testing facility. This facility is capable of varying the engine speed and load over a given time period. To measure the engine emissions, an emission analyser has been used to measure CO2, CO, THC, and NOx emissions. The fuels used in the analyses are 25% (25B) and 100% (100B) of biodiesel blend and diesel. The series of the transient events studied are speed changes from 900 to 1200rpm, 1200 to 1500rpm and 1500 to 1800rpm over a time period of 4 seconds each. These tests were performed at a constant load of 105Nm, 210Nm, 315Nm and 420Nm. The transient test results have shown that the emissions of CI engine running on biodiesel were reduced by up to 17%, 52% and 38% for CO, CO2 and THC emissions respectively as compared to diesel fuel. However, the NOx emission was seen to be 17% higher for engine running on biodiesel than that on diesel during transient conditions