Faculty Publications
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Item Effects of wet compression on the flow behavior of a centrifugal compressor: A CFD analysis(American Society of Mechanical Engineers (ASME) infocentral@asme.org, 2014) Anish, A.; Kim, H.D.Wet compression has been emerging as a prominent method for augmenting net power output from land based gas turbine engine. It is proven more effective than the conventional inlet cooling methods. In this method, fine water droplets are injected just upstream of the compressor impeller. These water droplets absorb the latent heat of evaporation during the compression process of gas-water droplet two-phase flow, consequently reducing the temperature rise. Many gas turbine engineers have performed the feasibility and usefulness studies on this wet compression, but physical understanding on the wet compression process is highly lacking, and related compression flow mechanism remains ambiguous. In the present study, a computational fluid dynamics method has been applied to investigate the wet compression effects on a low speed centrifugal compressor. A Langrangian particle tracking method was employed to simulate the air-water droplet twophase flow. The power saving achieved with different injection ratio of water droplets has been calculated and it is found that significant saving can be obtained with a water droplet injection ratio of above 3%. The vapor mass fraction varies linearly along the streamwise direction, making the assumption for a constant evaporation rate is valid. With the increase in the injection ratio the polytropic index for compression is coming down. The diffuser pressure recovery has been improved significantly with the wet compression; while the total pressure ratio across the impeller does not improve much. Contrary to the expectation, the evaporation rate is found to be coming down with the increase in the compressor mass flow rate. It is observed that the operating point, at which the peak pressure ratio occurs, shift towards higher mass flow rate during wet compression due to the local recirculation region within the vaneless space between the impeller and diffuser. © 2014 by ASME.Item Simulation and analysis of energy harvesting from grey water and rain water in high rises(Institute of Electrical and Electronics Engineers Inc., 2016) Kumar, K.R.; Kulgod, S.P.; Anish, A.Leading edge research on the renewable sources of energy is on a rise in order to meet the increasing energy demand. The objective of this project is to harvest potential energy inherent in tall buildings using micro-pelton turbine at the ground from grey water and rain water. Purified water is collected in separate tanks and a control system is designed for optimum power output from the micro-turbine which is analyzed computationally. With the escalating number of high rises and increasing awareness about renewable sources of energy, this source of energy can become a viable alternative. © 2016 IEEE.Item Computational investigation of the temperature separation in vortex chamber(Korean Society of Mechanical Engineers, 2014) Anish, A.; Setoguchi, T.; Kim, H.D.The vortex chamber is a mechanical device, without any moving parts that separates compressed gas into a high temperature region and a low temperature region. Functionally vortex chamber is similar to a Ranque-Hilsch vortex tube (RVHT), but it is a simpler and compact structure. The objective of the present study is to investigate computationally the physical reasoning behind the energy separation mechanism inside a vortex chamber. A computational analysis has been performed using three-dimensional compressible Navier-Stokes equations. A fully implicit finite volume scheme was used to solve the governing equations. A commercial software ANSYS CFX is used for this purpose. The computational predictions were validated with existing experimental data. The results obtained show that the vortex chamber contains a large free vortex zone and a comparatively smaller forced vortex region. The physical mechanism that causes the heating towards periphery of the vortex chamber is identified as the work done by the viscous force. The cooling at the center may be due to expansion of the flow. The extent of temperature separation greatly depends on the outer diameter of the vortex chamber. A small amount of compression is observed towards the periphery of the vortex chamber when the outer diameter is reduced. © 2014 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.