Faculty Publications
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Item Modeling of single and multilayer polyvinylidene fluoride film for micro pump actuation(2010) Karanth P, P.N.; Desai, V.; Kulkarni, S.M.Micro pumps are essential components of micro devices such as drug delivery systems. Large numbers of pumps have been proposed based on different actuating principles. Piezoelectric actuation offers advantages such as reliability and energy efficiency. Lead zirconate titanate (PZT) based piezoelectric actuation for micro pumps is predominantly explored despite its disadvantages such as brittle nature, low straining and difficulties in processing. Polymer piezoelectric materials like polyvinylidene fluoride (PVDF) could be promising replacements for PZT owing to their availability in form of films and good strain coefficients. Very limited literature on micro pump with PVDF as an actuator is available. In this paper, finite element analysis (FEA) model of a micro pump actuator using single and multilayer PVDF for actuation is developed in ANSYS. The model takes into account the influence of driving voltage and actuator. Copyright © Springer-Verlag 2009.Item Harnessing maximum power from solar PV panel for water pumping application: A simple approach(2012) Kappali, M.; Uday Kumar, R.Y.Among alternate sources of electricity, solar photovoltaic (PV) energy is gaining prominence due to its plentiful availability. Water pumping is an important application of solar PV power. However people are not opting for it in large numbers as "cost per watt" for solar pumping systems is high and the reliability is poor due to complex technology. The cost can be reduced by harnessing more power per unit installed capacity of the solar panel. One of the methods of realizing this is by Maximum Power Point Tracking (MPPT) wherein a power electronic converter is used to match pump with the PV panel. Currently "panel power" is the widely employed control parameter for MPPT. This approach can be referred to as MPPTPP. Present paper proposes load voltage as control parameter for MPPT. Varying the duty cycle of the MPPT converter such that load voltage is always maximum leads to harnessing maximum power output. This approach can be referred to as MPPTLV. Here only one parameter i.e. load voltage needs to be monitored. MPPTLV is simpler than MPPTPP as in the latter case it"s necessary to measure both panel voltage and current and then find their product. The proposed method is substantiated by theoretical explanation followed by simulation as well as experimentation results. The system considered is a standalone PV source connected to Permanent Magnet (PM) brushed DC motor driving centrifugal pump.Item Saltwater intrusion in coastal aquifers subjected to freshwater pumping(2014) Mahesha, A.; Lakshmikant, P.Investigations are carried out to analyze the effect of freshwater pumping on saltwater intrusion in coastal aquifers in the presence of a semipervious subsurface barrier along the coast. A conceptual, unconfined aquifer with a subsurface barrier subjected to simultaneous freshwater pumping at single/multiple locations perpendicular to the coast is considered for the analysis. The location, width, and the conductivity of the subsurface barrier being held constant, the effect of freshwater pumping at seaward and landward locations from the barrier is investigated on the interface motion. The performance of the barrier is compared with a nonbarrier condition. The numerical model developed predicts the behavior of the saltwater-freshwater interface and the piezometric surface due to simultaneous pumping at single/multiple wells across the sea cost. The barrier is effective in checking the progress of saltwater for freshwater pumping on the landward side of the barrier compared to no barrier condition. The freshwater pumping on the seaward side of the barrier should be limited to smaller rates. Additionally, safer zones for simultaneous freshwater withdrawal are identified for single, two, three, and four wells without the advancement of saltwater intrusion. The results obtained are of general nature and would be useful in determining the ideal location and rate of freshwater withdrawal minimizing the saltwater intrusion in coastal aquifers. © 2014 American Society of Civil Engineers.Item Solar Load Voltage Tracking for Water Pumping: An Algorithm(Springer India sanjiv.goswami@springer.co.in, 2015) Kappali, M.; Udayakumar, R.Y.Maximum power is to be harnessed from solar photovoltaic (PV) panel to minimize the effective cost of solar energy. This is accomplished by maximum power point tracking (MPPT). There are different methods to realise MPPT. This paper proposes a simple algorithm to implement MPPTlv method in a closed loop environment for centrifugal pump driven by brushed PMDC motor. Simulation testing of the algorithm is done and the results are found to be encouraging and supportive of the proposed method MPPTlv. © 2014, The Institution of Engineers (India).Item Effect of Partial Shading on PV Fed Induction Motor Water Pumping Systems(Institute of Electrical and Electronics Engineers Inc., 2019) Mudlapur, M.; Ramana, V.V.; Damodaran, R.; Balasubramanian, B.; Mishra, S.Partial shading is one of the certain conditions in photovoltaic (PV) power plants. Often the panels get partially shaded due to soiling, clouds, and trees. The effect of shading is of high concern and importance especially in applications such as water pumps due to agricultural environments in which they are employed in. However, the research focus on PV fed pumps till date has been restricted to only uniform shading conditions. Unlike uniform shading conditions during maximum power tracking, where the panel voltage remains almost constant for an entire range of irradiance, partial shading offer conditions such as highly variable panel voltage and transitions of intermediate DC-DC power converter from continuous conduction mode to discontinuous conduction mode. These effects severely affect the performance of the power converter and, therefore, the power output of the pump. This paper presents a study on the effects caused by partial shading conditions on pumps through simulations and verified by experimentations. The simulation and experimental results are found to be in good agreement with each other. This research thus helps in understanding the detrimental effects caused by partial shading conditions and thus serves as a reference tool for practitioners who wish to study PV fed pumps. © 1986-2012 IEEE.Item Failure of a Cooling Water Pump Shaft(Springer, 2021) Sondar, P.R.; Kumar, J.K.R.; Chawla, S.; Dsilva, P.C.; Hegde, S.R.This study investigates the failure of an industrial cooling water pump which experienced a drive shaft failure. As per the fail-safe design, during adverse loading of the shaft, key should fail by shear. The key, if fails, can be easily replaced to resume the operation of the pump. However, this investigation reveals that both the key and the shaft failed due to materials processing issues. A detailed failure analysis was carried out including design calculations, visual inspection, dye penetrant inspection, magnetic particle inspection, hardness test, microstructural analysis, and fractography. The study found that the hardness of the shaft varied radially from the core to the surface. The subsurface of the shaft near the keyway, happened to be significantly softer than the key. During operation, the keyway widened by plastic deformation and caused rattling of the key. Due to rattling and vibration, the key developed numerous fatigue cracks and eventually failed by crack linkages. The shaft eventually failed by torsional shear near the midpoint of the keyway. The analysis adjudged hardness variation in the shaft due to materials processing issues as the root cause of the failure. © ASM International 2020.Item Performance comparison of piezo actuated valveless micropump with central excitation and annular excitation for biomedical applications(IOP Publishing Ltd, 2021) Mohith, S.; Karanth P, N.; Kulkarni, S.M.; Desai, V.; Patil, S.S.In recent years, microfluidic devices, particularly micropumps, are extensively utilized in biomedical applications. The micropump used in biomedical applications needs to possess precise delivery of fluids at requires rate and pressure. The present work proposes a valveless mechanical micropump with a disposable chamber integrated with a novel concept of annular excitation of the diaphragm to fulfil the need for precise delivery of fluids in biomedical applications. The proposed design of the micropump involves a reusable configuration of the amplified piezoelectric actuator (APA) for micropump actuation and a disposable pump chamber. The pumping of the fluids occurs through the oscillation of the silicone rubber bossed diaphragm. The performance of a mechanical micropump depends on the oscillation amplitude of the diaphragm. Thus, the conventional approach of central excitation of the bossed diaphragm is replaced by a novel approach of annular excitation intended to enhance the deflection range, thus the volumetric performance of the micropump. An experimental comparative study is carried out to assess the deflection characteristics of central excitation and annular excitation of the bossed diaphragm. The maximum deflection measured with the annularly excited configuration of the bossed diaphragm is about 1953.4 ± 8.00 µm at 150 V, 43.5 Hz, which is superior to the maximum deflection of centrally excited configuration delivering 717.99 ± 4.00 µm at 150 V, 9.5 Hz. Further, the experimental studies aimed to fabricate and characterize the micropump with central and annular excitation approaches. The proposed micropump with central excitation delivered the maximum water flow rate of about 7.192 ± 0.147 ml min-1 and backpressure of 0.294 kPa at 150 V, 5 Hz. However, the enhancement of the deflection characteristics of the bossed diaphragm under annular excitation leads to performance enhancement of the micropump with the flow rate of 95.10 ± 0.444 ml min-1 and backpressure of 1.472 kPa at 150, 30 Hz. © 2021 IOP Publishing Ltd.Item An effective standalone hybrid wind-photovoltaic water pumping system with reduced power converter count(John Wiley and Sons Ltd, 2021) Angadi, S.; Yaragatti, U.R.; Yellasiri, Y.; Raju, A.B.This article proposes a standalone hybrid wind-photovoltaic (PV) water pumping system (WPS) with minimal power electronics interface, simple composite control, and optimal energy management strategy (EMS) for effective utilization of both renewable sources. The proposed system consists of classic Perturb and Observe (P&O) algorithm applied to the boost converter of the solar PV system and voltage regulation algorithm/hill-climbing MPPT algorithm with zero steady-state oscillation (ZSSO) applied to bidirectional voltage source converter (VSC) of wind energy conversion systems (WECS) for optimal power extraction at all times. The constant voltage to frequency (V/F) ratio is ensured at the point of common coupling (PCC) for the entire operating range to avoid saturation in the self-excited induction generator (SEIG) and the induction motor (IM) pump. The energy management strategy is devised to effectively harness renewable energy from both sources while ensuring the DC-link voltage stability. The system forms compelling proposition, given the least converter count to integrate solar-PV and wind energy employing easy to implement control algorithms with optimal energy extraction. The results of simulation and experimental studies on the proposed system reveal the effectiveness of the composite controller in terms of energy utilization, constant flux operation, and power balance for the entire operating range. Additionally, system exhibits acceptable dynamic and steady-state behavior against variations in wind velocity, solar irradiation, and load. © 2021 John Wiley & Sons Ltd.Item Design and implementation of constant flux controller for VSI assisted SEIG feeding induction motor pump(Inderscience Publishers, 2022) Angadi, S.; Yaragatti, U.R.; Yellasiri, Y.; Raju, A.B.In small scale, stand-alone, wind-power generation employing self excited induction generator (SEIG), water pumping using an induction motor is a typical application. In this paper, a simple voltage regulation scheme for the constant flux operation of the inverter assisted SEIG feeding three-phase induction motor pump is presented. The behaviour of DC-link voltage, frequency, amplitude modulation index (ma) and the shaft speed for load and speed perturbations are discussed in detail. Also, the overall active and reactive power flow for constant flux operation at the point of common coupling (PCC) is analysed. The proposed work presents a simple and reliable controller for SEIG-based stand-alone system for frequency-dependent loads using only a DC-link voltage sensor. Detailed system simulations are performed using Matlab/Simulink and the results of a laboratory prototype are presented to validate the theoretical analysis and practical operability of the proposed system. © 2022 Inderscience Publishers. All rights reserved.Item Analysis of annularly excited bossed diaphragm for performance enhancement of mechanical micropump(Elsevier B.V., 2022) Mohith, M.; Karanth P, N.K.; Kulkarni, S.M.Piezo actuated mechanical micropumps find extensive application in microfluidic devices for precise delivery of the fluids. The deflection of the diaphragm dramatically influences the performance of the mechanical micropump. The present work emphasises a novel method of annular excitation of the diaphragm to enhance the volumetric performance of the micropump. The proposed work incorporates a bossed diaphragm excited through a novel approach of annular excitation. The amplified piezoelectric actuator is used as a primary source of actuation. In the present work, theoretical and finite element methods are considered to analyse the deflection behaviour of the bossed diaphragm under central and annular excitation. Experimental characterisation is carried out to validate the results obtained from finite element analysis. The annular excitation of the bossed diaphragm delivers a higher range of deflection when compared with the conventional central excitation. The maximum simulated deflection of about 1998.4 µm is achieved with an annularly excited bossed diaphragm at 150 V, 45.5 Hz, which is far superior to the deflection range achieved with a conventional centrally excited bossed diaphragm with the deflection of 725.91 µm at 150 V, 9.96 Hz. The corresponding experimental deflection of annularly excited and centrally excited bossed diaphragm is about 1953.4 ± 8.00 µm at 50 V, 43.5 Hz and 717.99 ± 4.00 µm at 150 V, 9.5 Hz. © 2022 Elsevier B.V.