The Experts below are selected from a list of 297 Experts worldwide ranked by ideXlab platform
Hoi Dick Ng - One of the best experts on this subject based on the ideXlab platform.
-
EMBC - Optimization of drug viscosity used in gas-powered liquid jet injectors.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and, 2015Co-Authors: Rocco Portaro, Haruka Nakayama, Hoi Dick NgAbstract:This paper describes the effect of drug viscosity on the performance of gas powered liquid jet injectors. The analysis is accomplished utilizing a Computational Fluid Dynamics (CFD) model that obtains the Stagnation Pressure at the nozzle outlet. The technique is based on previous work used to predict gas power driven injector piston velocity with time. The results depict the variation in average and peak injector Stagnation Pressure for three different driven Pressures; driving injections which vary from 0.2 cP to 87 cP in viscosity. Furthermore, a numerical representation of jet shape is also obtained to verify the effect of viscosity on jet geometry. These results demonstrate that increasing viscosity by 10 times that of water produces only a slight decrease in injector Stagnation Pressure and produces jets with greater confinement, which will display better characteristics for puncturing the skin.
-
Optimization of drug viscosity used in gas-powered liquid jet injectors
2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015Co-Authors: Rocco Portaro, Haruka Nakayama, Hoi Dick NgAbstract:This paper describes the effect of drug viscosity on the performance of gas powered liquid jet injectors. The analysis is accomplished utilizing a Computational Fluid Dynamics (CFD) model that obtains the Stagnation Pressure at the nozzle outlet. The technique is based on previous work used to predict gas power driven injector piston velocity with time. The results depict the variation in average and peak injector Stagnation Pressure for three different driven Pressures; driving injections which vary from 0.2 cP to 87 cP in viscosity. Furthermore, a numerical representation of jet shape is also obtained to verify the effect of viscosity on jet geometry. These results demonstrate that increasing viscosity by 10 times that of water produces only a slight decrease in injector Stagnation Pressure and produces jets with greater confinement, which will display better characteristics for puncturing the skin.
-
Experimental analysis of the performance of an air-powered needle-free liquid jet injector
2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2013Co-Authors: Rocco Portaro, Hoi Dick NgAbstract:An experimental study was performed using a custom-built air-powered needle-free injector to investigate the various injector parameters governing the dynamics of jet injection. A parametric study using five different nozzle sizes at driver Pressure ranging from 4 to 8 bar was carried out. The fluid Stagnation Pressure of the liquid jet was determined using a Honeywell force sensor. Performance plots as a function of various parameters were constructed. It was determined that as the driver Pressure increased both the peak and average Stagnation Pressure increased almost linearly within the operating range considered. Varying the injection nozzle diameter, whilst keeping the driver Pressure constant did not have any significant impact on the peak or average Stagnation Pressure. The chamber length was also varied and no significant influence was found on peak or average Stagnation Pressure.
-
EMBC - Experimental analysis of the performance of an air-powered needle-free liquid jet injector
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and, 2013Co-Authors: Rocco Portaro, Hoi Dick NgAbstract:An experimental study was performed using a custom-built air-powered needle-free injector to investigate the various injector parameters governing the dynamics of jet injection. A parametric study using five different nozzle sizes at driver Pressure ranging from 4 to 8 bar was carried out. The fluid Stagnation Pressure of the liquid jet was determined using a Honeywell force sensor. Performance plots as a function of various parameters were constructed. It was determined that as the driver Pressure increased both the peak and average Stagnation Pressure increased almost linearly within the operating range considered. Varying the injection nozzle diameter, whilst keeping the driver Pressure constant did not have any significant impact on the peak or average Stagnation Pressure. The chamber length was also varied and no significant influence was found on peak or average Stagnation Pressure.
Jason Cassibry - One of the best experts on this subject based on the ideXlab platform.
-
One-dimensional radiation-hydrodynamic simulations of imploding spherical plasma liners with detailed equation-of-state modeling
Physics of Plasmas, 2012Co-Authors: J. S. Davis, Igor Golovkin, Joseph J. Macfarlane, Jason CassibryAbstract:This work extends the one-dimensional radiation-hydrodynamic imploding spherical argon plasma liner simulations of Awe et al. [Phys. Plasmas 18, 072705 (2011)] by using a detailed tabular equation-of-state (EOS) model, whereas Awe et al. used a polytropic EOS model. Results using the tabular EOS model give lower Stagnation Pressures by a factor of 3.9–8.6 and lower peak ion temperatures compared to the polytropic EOS results. Both local thermodynamic equilibrium (LTE) and non-LTE EOS models were used in this work, giving similar results on Stagnation Pressure. The lower Stagnation Pressures using a tabular EOS model are attributed to a reduction in the liner's ability to compress arising from the energy sink introduced by ionization and electron excitation, which are not accounted for in a polytropic EOS model. Variation of the plasma liner species for the same initial liner geometry, mass density, and velocity was also explored using the LTE tabular EOS model, showing that the highest Stagnation Pressure...
-
One-dimensional radiation-hydrodynamic scaling studies of imploding spherical plasma liners
Physics of Plasmas, 2011Co-Authors: C. S. Adams, J. S. Davis, D. S. Hanna, Jason CassibryAbstract:One-dimensional radiation-hydrodynamic simulations are performed to develop insight into the scaling of Stagnation Pressure with initial conditions of an imploding spherical plasma shell or “liner.” Simulations reveal the evolution of high-Mach-number (M), annular, spherical plasma flows during convergence, Stagnation, shock formation, and disassembly, and indicate that cm- and μs-scale plasmas with peak Pressures near 1 Mbar can be generated by liners with initial kinetic energy of several hundred kilo-joules. It is shown that radiation transport and thermal conduction must be included to avoid non-physical plasma temperatures at the origin which artificially limit liner convergence and, thus, the peak Stagnation Pressure. Scalings of the stagnated plasma lifetime (τstag) and average Stagnation Pressure (Pstag, the Pressure at the origin, averaged over τstag) are determined by evaluating a wide range of liner initial conditions. For high-M flows, τstag ∼ ΔR/v0, where ΔR and v0 are the initial liner thick...
Rocco Portaro - One of the best experts on this subject based on the ideXlab platform.
-
EMBC - Optimization of drug viscosity used in gas-powered liquid jet injectors.
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and, 2015Co-Authors: Rocco Portaro, Haruka Nakayama, Hoi Dick NgAbstract:This paper describes the effect of drug viscosity on the performance of gas powered liquid jet injectors. The analysis is accomplished utilizing a Computational Fluid Dynamics (CFD) model that obtains the Stagnation Pressure at the nozzle outlet. The technique is based on previous work used to predict gas power driven injector piston velocity with time. The results depict the variation in average and peak injector Stagnation Pressure for three different driven Pressures; driving injections which vary from 0.2 cP to 87 cP in viscosity. Furthermore, a numerical representation of jet shape is also obtained to verify the effect of viscosity on jet geometry. These results demonstrate that increasing viscosity by 10 times that of water produces only a slight decrease in injector Stagnation Pressure and produces jets with greater confinement, which will display better characteristics for puncturing the skin.
-
Optimization of drug viscosity used in gas-powered liquid jet injectors
2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015Co-Authors: Rocco Portaro, Haruka Nakayama, Hoi Dick NgAbstract:This paper describes the effect of drug viscosity on the performance of gas powered liquid jet injectors. The analysis is accomplished utilizing a Computational Fluid Dynamics (CFD) model that obtains the Stagnation Pressure at the nozzle outlet. The technique is based on previous work used to predict gas power driven injector piston velocity with time. The results depict the variation in average and peak injector Stagnation Pressure for three different driven Pressures; driving injections which vary from 0.2 cP to 87 cP in viscosity. Furthermore, a numerical representation of jet shape is also obtained to verify the effect of viscosity on jet geometry. These results demonstrate that increasing viscosity by 10 times that of water produces only a slight decrease in injector Stagnation Pressure and produces jets with greater confinement, which will display better characteristics for puncturing the skin.
-
Experimental analysis of the performance of an air-powered needle-free liquid jet injector
2013 35th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2013Co-Authors: Rocco Portaro, Hoi Dick NgAbstract:An experimental study was performed using a custom-built air-powered needle-free injector to investigate the various injector parameters governing the dynamics of jet injection. A parametric study using five different nozzle sizes at driver Pressure ranging from 4 to 8 bar was carried out. The fluid Stagnation Pressure of the liquid jet was determined using a Honeywell force sensor. Performance plots as a function of various parameters were constructed. It was determined that as the driver Pressure increased both the peak and average Stagnation Pressure increased almost linearly within the operating range considered. Varying the injection nozzle diameter, whilst keeping the driver Pressure constant did not have any significant impact on the peak or average Stagnation Pressure. The chamber length was also varied and no significant influence was found on peak or average Stagnation Pressure.
-
EMBC - Experimental analysis of the performance of an air-powered needle-free liquid jet injector
Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and, 2013Co-Authors: Rocco Portaro, Hoi Dick NgAbstract:An experimental study was performed using a custom-built air-powered needle-free injector to investigate the various injector parameters governing the dynamics of jet injection. A parametric study using five different nozzle sizes at driver Pressure ranging from 4 to 8 bar was carried out. The fluid Stagnation Pressure of the liquid jet was determined using a Honeywell force sensor. Performance plots as a function of various parameters were constructed. It was determined that as the driver Pressure increased both the peak and average Stagnation Pressure increased almost linearly within the operating range considered. Varying the injection nozzle diameter, whilst keeping the driver Pressure constant did not have any significant impact on the peak or average Stagnation Pressure. The chamber length was also varied and no significant influence was found on peak or average Stagnation Pressure.
S V Prabhu - One of the best experts on this subject based on the ideXlab platform.
-
theoretical study on the prediction of the hydrodynamic performance of a savonius turbine based on Stagnation Pressure and impulse momentum principle
Energy Conversion and Management, 2018Co-Authors: Vimal Patel, T I Eldho, S V PrabhuAbstract:Abstract A theoretical study is introduced to predict the hydrodynamic performance of a vertical axis Savonius turbine with semicircular vanes. This theory is based on the concept of Stagnation Pressure rise at the turbine vanes and Newton’s second law of impulse momentum principle. The present theory predicts the performance of a Savonius rotor with semicircular vane including overlapping vanes. Although the present model is derived for semicircular vanes, it can also be used for any type of the vanes with minor modifications. For the validation of an investigated theory, the results obtained by the presented theory is compared with the experimental results available in the published literatures. The comparison of the results are done for two major cases of the Savonius turbine, i. Turbine with an end plate and ii. Turbine without end plates for low aspect ratio. The calculation shows that, the theoretically calculated results predicts the maximum power within 3.6% and maximum coefficient of power within 6.67% variation. It can be conclude that the present theory will be most useful to decide the best design configurations of Savonius turbine unit for specific available flow conditions and quick performance prediction of a Savonius turbine for different operating conditions.
-
Velocity measurement in low Reynolds and low Mach number slip flow through a tube
Experimental Thermal and Fluid Science, 2015Co-Authors: Vijay Varade, S V Prabhu, Amit Agrawal, A. M. PradeepAbstract:This paper presents an experimental procedure and results of velocity measurement in the slip flow regime. The measurements are for nitrogen gas flowing at low Pressure (flow Reynolds number: 4–198, Mach number: 0.05–0.12) in a conventional tube of 16 mm internal diameter. The static Pressure is measured at the wall of the tube and the Stagnation Pressure is measured through a Pitot tube, for different mass flow rates. The velocity is estimated by applying Stagnation Pressure correction proposed by earlier researchers, as the Bernoulli equation cannot be applied in gas flow for Rep < 30. In the slip regime, the Stagnation Pressure correction is found to be a function of Reynolds number and a weak function of rarefaction. A new correlation for Stagnation Pressure correction is also proposed. Using this correction, velocity within ±8% with reference to the analytical solution is obtained. These results are not previously available and should help in velocity measurement ability of low Reynolds number slip flows.
Jovan Isakovic - One of the best experts on this subject based on the ideXlab platform.
-
cascade nonlinear feedforward feedback control of Stagnation Pressure in a supersonic blowdown wind tunnel
Measurement, 2017Co-Authors: Biljana Ilic, Marko Milos, Jovan IsakovicAbstract:Abstract Current trends in the development of control systems involve disproportionately high costs for embedded software integration and testing techniques that rely almost exclusively on exhaustive testing of more or less complete versions of complex systems. Wind tunnel control systems are not an exception. A formal methodology for supersonic flow control does not exist, which is not acceptable from a perspective of cost, reliability and safety of wind tunnel operations. The cascade nonlinear feedforward-feedback Stagnation Pressure controller proposed here is intended to address this deficiency in the operation of a supersonic blowdown wind tunnel. By focusing on a model-based approach using physical principles and hierarchical design methodologies, a systematic design method is offered for Stagnation Pressure control in particular, and control of flow parameters in general. The suggested mathematical model of supersonic flow in a blowdown wind tunnel is analyzed and main challenges of using a model-based approach are identified, with an emphasis on high process nonlinearity and an infinite number of possible operating conditions. The model is applied to the VTI Belgrade T-38 blowdown wind tunnel to identify the feedforward component that accurately predicts the nonlinear response of the facility. The Simulink® models of the facility and the proposed controller are developed to tune the feedback component in numerical simulations and verify the controller. The wind tunnel control system is implemented as an embedded distributed hierarchical system and experiments to verify the suggested control method are realized at Mach numbers 1.0–4.0. Both simulations and experiments demonstrate that feedback calculation successfully captures nonlinearities in the facility response, enabling a simple linear feedback controller with a single set of control terms to be used only to trim out additional deviations for an entire operating range of the facility. The feedforward-feedback architecture thus improves setpoint reference tracking, while the cascade architecture improves disturbance rejection performance compared to common single loop solutions. Combined within a single system, they eliminate large transient Pressure overshoots typical for blowdown facilities, decrease the setpoint settling time and improve overall Stagnation Pressure control accuracy. In addition, system integration and testing time and costs are significantly reduced by analyzing physical properties of the process and taking them into consideration during early stages of the system development.
-
Stagnation Pressure transient control in a supersonic blowdown wind tunnel test facility
Materials Today: Proceedings, 2016Co-Authors: Biljana Ilic, Mirko Milosavljevic, Jovan Isakovic, Marko MilosAbstract:Abstract Research in the area of wind tunnel flow parameters control has been intensified in recent years, in an attempt to improve quality and efficiency of the wind tunnel operation. In this paper, Stagnation Pressure transient control in a supersonic blowdown-type wind tunnel is considered, with the aim of increasing available measurement time and bringing improvement in the operation efficiency. The Stagnation Pressure control strategy in the VTI Belgrade T-38 wind tunnel is analyzed. A mathematical model of a blowdown wind tunnel is developed and applied to the T-38 test facility. The model is used to incorporate a modified Stagnation Pressure transient control in the original T-38 control system, in order to establish the required Stagnation Pressure with the shortest possible settling time. The actual wind tunnel tests confirm model-predicted decrease of the Pressure settling time and increase of available measurement time, bringing significant improvement in the facility operation efficiency.
-
model based Stagnation Pressure control in a supersonic wind tunnel
FME Transactions, 2016Co-Authors: Biljana Ilic, Mirko Milosavljevic, Marko Milos, Jovan IsakovicAbstract:The flow parameters control in wind tunnels is an area of intense research in recent years, with the aim of improving quality and efficiency of the wind tunnel operation. In this paper, an attempt is made to contribute to a better understanding of the Stagnation Pressure control in supersonic blowdown-type facilities. The Stagnation Pressure control strategy in the VTI Belgrade T-38 wind tunnel is discussed. An improved mathematical model for a supersonic wind tunnel is suggested and applied to the T-38 facility. Comparisons of simulation and experimental data are made to demonstrate accurate prediction of the facility response in supersonic flow conditions by the mathematical model. The model is used to incorporate a modified feedforward control in the original T-38 wind tunnel control system. The actual wind tunnel tests confirm model-predicted decrease of flow stabilization time and increase of available measurement time, bringing significant improvement in the wind tunnel operation efficiency.