Gamma Technologies Inc.
Gamma Technologies Inc.
Ghadirian E.,Gamma Technologies Inc. |
Abbasian J.,Illinois Institute of Technology |
Arastoopour H.,Illinois Institute of Technology
Powder Technology | Year: 2017
Carbon dioxide is the primary greenhouse gas emitted through human activities; therefore, efficient reduction of CO2 is regarded as one of the key environmental challenges of the current century. Different processes have been introduced in the literature for CO2 capture; among these, solid sorbent processes have shown potential advantages such as easy regeneration and high capacity. In order to achieve steady CO2 capture using solid sorbents, a circulating fluidized bed (CFB) is used that consists mainly of a carbonator reactor (where the CO2 is adsorbed by solid sorbents) and a regenerator (where carbonated sorbents release CO2 and a concentrated CO2-steam mixture is produced). Different solid sorbents have been developed to be utilized in carbon capture units such as MgO-based sorbents and CaO-based sorbents. In this study, an MgO-based solid sorbent was used due to its capability to capture CO2 at high temperature (300–550 °C), which is in the vicinity of the operating conditions of advanced power plants (e.g., integrated gasification combined cycles [IGCC]). The use of MgO-based sorbents results in a lower energy penalty in the carbonation/regeneration cycle of MgO-based sorbents. In this study, three-dimensional computational fluid dynamics (CFD) simulations of the regeneration unit of the carbon capture process using MgO-based solid sorbents were investigated and the performance of the fluidized bed regenerator unit (operating at different conditions) was studied. © 2017 Elsevier B.V.
Seldon W.,General Motors |
Hamilton J.,General Motors |
Cromas J.,Gamma Technologies Inc. |
Schimmel D.,Gamma Technologies Inc.
SAE Technical Papers | Year: 2017
As regulations become increasingly stringent and customer expectations of vehicle refinement increase, the accurate control and prediction of induction system airborne acoustics are a critical factor in creating a vehicle that wins in the marketplace. The goal of this project was to improve the predicative accuracy of a 1-D GT-power engine and induction model and to update internal best practices for modeling. The paper will explore the details of an induction focused correlation project that was performed on a spark ignition turbocharged inline four-cylinder engine. This paper and SAE paper "Experimental GT-POWER Correlation Techniques and Best Practices" share similar abstracts and introductions; however, they were split for readability and to keep the focus on a single a single subsystem. This paper compares 1D GT-Power engine air induction system (AIS) sound predictions with chassis dyno experimental measurements during a fixed gear, full-load speed sweep. The engine is a turbocharged, spark ignition I4. The air induction system includes an air box, centrifugal compressor, and charge air cooler. Engine performance predictions were first compared with measurements, in terms of brake torque and intake manifold temperature, to confirm that the model is capturing reduced performance during elevated air temperature in the intake manifold. Then, the GEM3D models of the air box and charge air cooler are discussed, along with the compressor acoustic model. The transmission loss of the air box is compared with experimental data. The predicted sound at the 2nd and 4th engine orders is compared with measurements, which shows reasonable agreement. The primary takeaway from the project is the importance of correctly modeling the geometry in detail and matching the exact operating conditions between test and CAE. Copyright © 2017 SAE International.
Seldon W.,General Motors |
Shoeb A.,General Motors |
Schimmel D.,Gamma Technologies Inc. |
Cromas J.,Gamma Technologies Inc.
SAE Technical Papers | Year: 2017
As regulations become increasingly stringent and customer expectations of vehicle refinement increase, the accurate control and prediction of exhaust system airborne acoustics are a critical factor in creating a vehicle that wins in the marketplace. The goal of this project was to improve the predicative accuracy of the GT-power engine and exhaust model and to update internal best practices for modeling. This paper will explore the details of an exhaust focused correlation project that was performed on a naturally aspirated spark ignition eight-cylinder engine. This paper and SAE paper "Experimental GT-POWER Correlation Techniques and Best Practices Low Frequency Acoustic Modeling of the Intake System of a Turbocharged Engine" share similar abstracts and introductions; however, they were split for readability and to keep the focus on a single a single subsystem. This paper compares 1D GT-Power exhaust external sound predictions with chassis dyno experimental measurements during a fixed gear, full-load speed sweep. The exhaust system includes an X-pipe and modeling with use of GEM 3D. Predictions were compared with measurements, in terms of overall sound and relevant orders, both with and without (replaced by straight pipes) mufflers. The primary takeaway from the project is the importance of correctly modeling the geometry in detail utilizing GEM3D and capturing the temperature gradient. Copyright © 2017 SAE International.
Ghadirian E.,Gamma Technologies Inc. |
Arastoopour H.,Illinois Institute of Technology
Particuology | Year: 2017
Dense gas–solid flows show significantly higher stresses compared with dilute flows, mainly attributable to particle–particle friction in dense particle flows. Several models developed have considered particle–particle friction; however, they generally underestimate its effect in dense regions of the gas–solid system, leading to unrealistic predictions in their flow patterns. Recently, several attempts have been made to formulate such flows and the impact of particle–particle friction on predicting flow patterns based on modified frictional viscosity models by including effects of bulk density changes on frictional pressure of the solid phase. The solid–wall boundary is also expected to have considerable effect on friction because particulate phases generally slip over the solid surface that directly affects particle–particle frictional forces. Polydispersity of the solid phase also leads to higher friction between particles as more particles have sustained contact in polydispersed systems. Their effects were investigated by performing CFD simulations of particle settlement to calculate the slope angle of resting material of non-cohesive particles as they settle on a solid surface. This slope angle is directly affected by frictional forces and may be a reasonably good measure of frictional forces between particles. The calculated slope angle, as a measure of frictional forces inside the system are compared with experimental values of this slope angle as well as simulation results from the literature. © 2017 Chinese Society of Particuology and Institute of Process Engineering, Chinese Academy of Sciences
Arnett M.,Gamma Technologies Inc. |
Papadimitriou I.,Gamma Technologies Inc. |
Milios J.,Sendyne Corporation
2014 IEEE Transportation Electrification Conference and Expo: Components, Systems, and Power Electronics - From Technology to Business and Public Policy, ITEC 2014 | Year: 2014
In order to ensure high accuracy of complete hybrid powertrain simulations, it is important that models capture the temperature-sensitive behavior of the involved components and the flow of energy between subsystems. This paper presents the coupling of a battery Compact Physical Model (CPM) with a hybrid electric vehicle model, including the propulsion system and the thermal aspect of its components, as well as the entire cooling system. The resulting model can accurately predict the interactions between the various subsystems and the various energy paths and thus it can be used for thermal management analysis and control strategy optimization. © 2014 IEEE.
Kersey J.,Gamma Technologies Inc. |
Loth E.,University of Virginia |
Lankford D.,Aerospace Testing Alliance
AIAA Journal | Year: 2010
A methodology for simulating two-way multiphase coupling of mass, momentum, and energy was developed to investigate the effect of droplet mass and heat transfer on one-dimensional shock waves. The numerical approach employed a conservative formulation for the gas and a Lagrangian formulation for the particles. The approach was verified for one-way heat transfer, evaporation and condensation for low-speed flows, and for two-way shock attenuation for solid particles and small evaporating drops (for which breakup is not expected and internal temperature gradients are weak). Parametric studies were conducted to investigate the coupling physics, and, surprisingly, finite rate evaporation and two-way coupling were found to increase the rate of shock attenuation and reduce the postshock gas temperature for mass loadings as small as 0.5%. Larger drops led to long regions of nonequilibrium as did, unexpectedly, effects of evaporation. Copyright © 2010.
Bissett E.J.,Gamma Technologies Inc. |
Kostoglou M.,Aerosol and Particle Technology Laboratory |
Kostoglou M.,Aristotle University of Thessaloniki |
Konstandopoulos A.G.,Aerosol and Particle Technology Laboratory |
Konstandopoulos A.G.,Aristotle University of Thessaloniki
Chemical Engineering Science | Year: 2012
In the 1D modeling of flow in the channels of wall-flow monoliths used in diesel particulate filters for engine exhaust emissions control, it is common to use friction coefficients and Nusselt numbers from idealized 2D/3D channel flows with zero wall flow. This practice implicitly makes the additional approximation that the actual velocity and scalar (temperature or species concentrations) profiles within the channels are little affected by nonzero wall flow. There is extensive related research in the filtration literature for the simpler geometries of circular tubes and parallel planes that exposes much more complex and interesting effects as the wall Reynolds number, Re w, increases. Here we extend these results to the 3D geometry of square channels appropriate for wall-flow monoliths. We solve for the fully developed laminar flow, and heat transfer, within long square channels with porous walls and uniform wall velocity. Results are generated for the appropriate parameter range applicable for the diesel particulate filter application which provide the corrected friction coefficients and Nusselt numbers for nonzero Re w. Furthermore, we confirm the observation, from prior work on the simpler geometries that there exists a limiting Re w beyond which there is no fully developed flow for the inlet channels (wall suction). Implications for modeling diesel particulate filters are discussed. © 2012 Elsevier Ltd.
Harrison J.,Gamma Technologies Inc. |
Aihara R.,Gamma Technologies Inc. |
Eisele F.,SHW Automotive GmbH
SAE International Journal of Engines | Year: 2016
Engine and transmission oil systems are commonly pressurized by gerotor style pumps, due to their simplistic design and low cost. Gerotor pumps are designed with certain tolerances of the gears and housing, thus creating a tradeoff of lower cost with larger tolerances and higher cost with smaller tolerances. By building a detailed gerotor pump model with a 1D hydraulic flow network, engineers can evaluate pump performance with these tolerances as input and compare to find the optimal design. This paper showcases the ease of building a gerotor model in 1D by using an automated process extracting the key model inputs directly from the pump CAD file. The gerotor pump performance is predicted including flow rate, total power loss, volumetric efficiency, and total efficiency vs. pump speed, pressure rise, clearance tolerances, and temperature, and compared with experiment. A predictive friction model for gerotor pumps is proposed and total torque required to drive the pump is compared directly with experiment. Additionally, an internal leakage model for predicting volumetric efficiency taking into account physical clearance between inner and outer gears, as well as temperature is discussed. Copyright © 2016 SAE International.
Lynch B.,Gamma Technologies Inc.
ASME 2015 Internal Combustion Engine Division Fall Technical Conference, ICEF 2015 | Year: 2015
Durability is a prime concern in the design of hydraulic systems and fuel injectors [1-3] thus an accurate prediction of impact velocities between components and the flow through them is essential to assessing concepts. Simulation of these systems is difficult because the geometries are complex, some volumes go to zero as the components move, and the flow at a single operating condition generally spans Reynolds numbers less than 1 to more than 104[4-8]. As a result of these challenges, experimental testing of prototypes is the dominant method for comparing concepts. This approach can be effective but is far more costly, time consuming, and less flexible than the ability to run simulations of concepts early in the design cycle. A validated model of a fuel injector built from publicly available data  is used to present a new approach to modelling hydraulic systems which overcomes many of these obstacles. This is accomplished by integrating several commercially available tools to solve the physics specific to each area within the fuel injector. First, the fuel injector is simulated using a 3D CFD simulation integrated with a 1D CFD system model. The flow in various regions of the injector is then analyzed to determine if the fluid models in these areas can be simplified based on the flow regime. Based on this analysis, a combination of models is assembled to improve the quality of the simulation while decreasing the time required to run the model. The fuel injector is simulated using a multibody dynamics model coupled to a reluctance network model of the solenoid and several fluid models. The first is a 3D CFD simulation which uses novel mesh refinement techniques during runtime to ensure high mesh quality throughout the motion of components, to resolve the velocity profile of laminar flows, and to satisfy the requirements of the RNG k-ε turbulence model and wall functions. This approach frees the analyst from defining the mesh before runtime and instead allows the mesh to adapt based on the flow conditions in the simulation. Due to the highly efficient meshing algorithm employed, it is possible to re-mesh at each timestep thus ensuring a high quality structured mesh throughout the simulation duration. Then a 3D FEM solution to the Reynolds Equation and a statistical contact model is employed to solve for the squeeze films between components and to allow separation and contact between bodies in the control valve. These detailed simulations are integrated with a 1D flow model of the fuel injection system. The results from the detailed coupled simulations are compared to the results from simpler 1D models and measured data to illustrate under which operating conditions a more advanced technique incorporating 3D CFD is worth the additional computational expense versus a traditional 1D model. Copyright © 2015 by ASME.
Gundlapally S.R.,University of Houston |
Gundlapally S.R.,Gamma Technologies Inc. |
Balakotaiah V.,University of Houston
Chemical Engineering Science | Year: 2013
We study the effect of the substrate material (ceramic versus metallic) on the steady-state and transient performance of monolith reactors using a one-dimensional two-phase model with position dependent transfer coefficients. When the operation of the reactor is on the ignited branch, it is shown that monoliths with metallic substrate clearly lead to a superior steady-state performance compared to those with ceramic substrate. In such cases, the ignited branch extends to lower inlet gas temperatures (typically 60-100 °C in after-treatment applications) for the same catalyst loading. For transient operation where the time to light-off is important, it is shown that for the case of back-end ignition (corresponding to low inlet temperatures or low catalyst loading), metallic substrates are again superior. However, for the case of front-end ignition, ceramic converters may lead to lower cumulative emissions at lower inlet gas velocities while the converse is true at higher velocities. It is shown that the transient heating time and hence the cumulative emissions decrease with decrease in the channel hydraulic diameter and thermal capacitance of the substrate but are not monotonic with the inlet gas velocity. We present mathematical analysis and simulations to support these conclusions. Some novel results on the effect of substrate conductivity on the number of steady-states and upstream propagation of temperature fronts are also presented. © 2013 Elsevier Ltd.