Mechanical Engineeringhttp://repository.iitgn.ac.in/handle/123456789/5872017-05-23T16:51:27Z2017-05-23T16:51:27ZGlobal stability analysis of axisymmetric boundary layer over a circular coneBhoraniya, RameshNarayanan, Vinodhttp://repository.iitgn.ac.in/handle/123456789/29422017-05-23T09:55:49Z2017-04-01T00:00:00ZGlobal stability analysis of axisymmetric boundary layer over a circular cone
Bhoraniya, Ramesh; Narayanan, Vinod
This paper presents linear biglobal stability analysis of axisymmetric boundary layer over a circular cone. An incompressible flow over a sharp circular cone is considered with zero angle of attack. The base flow velocity profile is fully non-parallel and non-similar. Linearized Navier-Stokes (LNS) equations are derived for disturbance flow quantities using the standard procedure. The LNS equations are discretized using Chebyshev spectral collocation method. The governing equations along with boundary conditions form a general eigenvalues problem. The numerical solution of general eigenvalues problem is obtained using ARPACK subroutine, which uses Arnoldis iterative algorithm. The global temporal modes are computed for the range of Reynolds number and semi-cone angles(α)for the axisymmetric mode(N=0). The flow is found temporally and spatially stable for 1° semi-cone angle and the range of Reynolds numbers considered. However, flow becomes temporally unstable and spatially stable with the increase in semi-cone angle(α). The wave-like behaviour of the disturbances is found at small semi-cone angles (α).
2017-04-01T00:00:00ZAn input reconstruction approach for command following in linear MIMO systemsChavan, Roshan A.Kadam, Sujay D.Rajiv, AbhijithPalanthandalam-Madapusi, Harish J.http://repository.iitgn.ac.in/handle/123456789/28992017-04-28T14:01:22Z2017-04-01T00:00:00ZAn input reconstruction approach for command following in linear MIMO systems
Chavan, Roshan A.; Kadam, Sujay D.; Rajiv, Abhijith; Palanthandalam-Madapusi, Harish J.
2017-04-01T00:00:00ZRevisiting trackability for linear time-invariant systemsKadam, Sujay D.Palanthandalam-Madapusi, Harish J.http://repository.iitgn.ac.in/handle/123456789/28952017-04-28T09:09:47Z2017-05-24T00:00:00ZRevisiting trackability for linear time-invariant systems
Kadam, Sujay D.; Palanthandalam-Madapusi, Harish J.
2017-05-24T00:00:00ZOxidative steam reforming of ethanol on rhodium catalyst – I: Spatially resolved steady-state experiments and micro kinetic modelingBaruah, RenikaDixit, MarmParejiya, AnandBasarkar, PratikBhargav, AtulSharma, Sudhanshuhttp://repository.iitgn.ac.in/handle/123456789/28872017-04-27T11:25:18Z2017-04-01T00:00:00ZOxidative steam reforming of ethanol on rhodium catalyst – I: Spatially resolved steady-state experiments and micro kinetic modeling
Baruah, Renika; Dixit, Marm; Parejiya, Anand; Basarkar, Pratik; Bhargav, Atul; Sharma, Sudhanshu
Oxidative steam reforming of ethanol is an important process for on board production of hydrogen in fuel cell based auxiliary power systems. Although the process has been extensively studied from a catalyst perspective, accurate models that capture species and temperature information required by model-based control algorithms during operation have not yet been developed adequately. In this work, we develop a reduced micro-kinetic model for ethanol oxidative steam reforming, which can be used in computational fluid dynamics (CFD) studies and subsequently to develop model-based control strategies. We experimentally study cordierite monolith based reactors in which Rh/CeO2 catalysts are prepared by the solution-combustion method. The catalyst system is characterized by X-ray diffraction (XRD), Scanning Electron Microscope (SEM), temperature programmed reduction and temperature programmed desorption analyses. The experimental reformer design enables measurement of species concentrations at various points along the reactor length, along with radial temperature profiles. A micro-kinetic model is adapted from the literature and validated against these experiments, with good agreement. The model results suggest a linear activation pathway for ethanol over rhodium catalysts by forming ethoxide, acetyl and acetate intermediates. After formation of single carbon species, the methane reforming pathway is followed. We expect that these studies, when coupled with transient studies will help in formulating model-based control strategies for ethanol reformers in complex fuel cell systems.
2017-04-01T00:00:00Z