Kunio Kataoka - Academia.edu (original) (raw)
Papers by Kunio Kataoka
Journal of Chemical Engineering of Japan, 2004
ABSTRACT
Industrial & Engineering Chemistry Research, Aug 18, 2001
This paper presented a non-steady-state operation for controlling latex particle size distributio... more This paper presented a non-steady-state operation for controlling latex particle size distribution by using continuous emulsion polymerization of vinyl acetate. The experiment was conducted in a CSTR under conditions below the critical micelle concentration of the emulsifier. The monomer conversion attained in the time-independent steady-state operation showed a dramatic rise from nearly 0 to over 60% at the mean residence time of the continuously stirred tank reactor (CSTR), τ c) 22 min. The mean residence time was switched alternately between two values in the non-steady-state operation, one giving zero monomer conversion and the other a high monomer conversion in the usual steady-state operation. The periodic-switching operation induced oscillations in monomer conversion in time. When the switching interval was sufficiently long as compared with the mean residence time, the particle size distribution (PSD) varied synchronously with the switching operation. The present work showed the possibility of controlling the temporal PSD by adjusting the frequency and/or the amplitude of the temporal variation of the mean residence time.
Journal of Fluids and Structures, Apr 1, 2005
The stability of the helical flow in a system of coaxial rotating conical cylinders, the inner on... more The stability of the helical flow in a system of coaxial rotating conical cylinders, the inner one rotating and the outer one stationary was experimentally investigated. The helical flow resulted from a Hopf bifurcation, which occurred only when the acceleration of the inner conical cylinder was smaller than 0.06 rad/s 2. When the rotational speed of the inner conical cylinder was increased, the transition to turbulence occurred following a succession of flow states: (i) threedimensional laminar flow (TDLF), (ii) laminar periodic helical flow (LPHF), (iii) doubly periodic wavy helical flow (DWHF), (iv) weakly turbulent helical flow (WTHF) and (v) fully turbulent helical flow (FTHF). Time series obtained by an electrochemical method permitted the identification and analysis of the fundamental frequencies and their evolutions associated with each time-dependent flow state, using Fourier and wavelet transforms. Phase space analysis revealed the associated attractors constructed from the embedded time series. In the FTHF flow state, the fundamental frequency of the helical flow was observed to have a ratio to the rotational frequency of almost twice that of the one measured in the LPHF regime.
Laser Techniques Applied to Fluid Mechanics, 2000
Tbe purpose of the experimental work is to elucidate the mechanism for the occurrence of chaos in... more Tbe purpose of the experimental work is to elucidate the mechanism for the occurrence of chaos in a Taylor-Couette flow system. Tbe attention was focused on the higher instability region from the doubly-periodic to the weaklyturbulent wavy vortex flow. In order to take note of the effect of hysteresis, the inner cylinder rotation was accelerated at a constant rate from rest until a specified Reynolds number was reached. Tbe test section with the radius ratio of 0.625 had an annular gap width of 22.5 mm and an aspect ratio of 4. A fiberoptic laserDoppler velocimeter was employed to observe a time-dependent, peripheral component of velocity at the central region of vortex ceHs. At the same time, timedependent peripheral component of velo city gradients on the wall of the stationary outer cylinder were measured in the neighborhood of one of the outflow ceH boundaries with a hot-film shear sensor embedded flush with the inside cylindrical surface. Four vortex ceHs were always formed regardless of the acceleration rate of the inner cylinder rotation tested in the start-up operation, but the axial wavelength of the two central vortices was shorter than that of the remaining two end vortices. The amplitudes of the fluctuations of velocity and velocity-gradient varied irregularly whereas the first fundamental frequency was maintained in proportion to the inner cylinder rotation as long as the azimuthaIly-traveling waves existed. It has been conc1uded that chaos occurs firstly at the inflow cell boundaries as a result of instabiIity in the viscous interaction of end vortices with the fixed bottom and top surfaces and that the chaotic turbulence is propagated along the secondary flow streamlines toward the central vortices and penetrated very slowly toward the center of vortex cells.
Journal of Chemical Engineering of Japan, 2008
This is an experimental and analytical report of the second-phase national research project of en... more This is an experimental and analytical report of the second-phase national research project of energy-saving heat integrated distillation column (HIDiC) technology applied to multi-component hydrocarbon distillation processes downstream of the naphtha cracking process. The first column of an existent commercial-scale distillation plant extracting cyclopentane from multi-component hydrocarbon mixtures was selected as the model column of the HIDiC project. The actual operation data were employed not only for the specification of distillation system design but also for the energy-saving analysis. A commercial-scale HIDiC pilot plant has been constructed based on the computer-aided HIDiC design of system and operation. A comparison of the test operation data was made with the computer simulation taking into account the power consumption of the compressor installed between the rectifying and stripping sections. It has been confirmed that the energy conservation level better than the design specification can be attained by means of the actual internal heat integration of the HIDiC pilot plant. The target of energy saving more than 50% of the energy consumption of the existent conventional distillation column (model column) was achieved in various operation conditions. The energy saving higher than 76% was achieved under the condition when the external reflux ratio was reduced to zero. The stable continuous HIDiC operation for 1,000 hr has successfully been realized by the pilot plant.
Theoretical and applied mechanics Japan, 2002
Proceedings of thermal engineering conference, 2001
The purpose qf thr present work is to investigate the transition from periodic to chaotic flows i... more The purpose qf thr present work is to investigate the transition from periodic to chaotic flows in Taylor vortex flow with the aid of a wavelet analysis ． Time series data of fl ロctuating tangential velocity were obta 血 ed with afiberoptic laser −DDppler velocimeter ． To c］ arjfy the dependence of time − fluc 加 ation flow properties on spatial location ， the velocity was measured at several positions with each ' vo 煙 ex ． Ih order to estimate wavelet cor 爬 lation pattems ， logarithmic expectation and information entropy were calculated at each time scale ． コhe wave 】 et paロ ems
International Journal of Heat and Mass Transfer, 1987
The mechanism for the enhancement of stagnation-point heat transfer was explored analyzing the la... more The mechanism for the enhancement of stagnation-point heat transfer was explored analyzing the large-scale turbulent structures of an impinging round jet by a statistical technique with conditional sampling. It has been found that large-scale eddies impinging on the heat transfer surfaces produce a turbulent surface-renewal effect dominant for the enhancement of the jet impingement heat transfer. The effect of heat transfer enhancement can be described in terms of the turbulent Reynolds and Strouhal numbers based on the characteristic turbulence intensity and frequency of the large-scale eddies impinging on the stagnation-point boundary layer.
Proceeding of International Heat Transfer Conference 8, 1986
ABSTRACT
A fermented mash liquid (3,000 kg/h, 5 wt% ethanol) is firstly enriched up to near-azeotropic poi... more A fermented mash liquid (3,000 kg/h, 5 wt% ethanol) is firstly enriched up to near-azeotropic point by using a compressor-free HIDiC (Heat Integrated Distillation Column) system developed by our NEDO project. This system consists of a mash column followed by a double-tube HIDiC trayed column. The mash column operated at 1 atm supplies vapour into the bottom of HIDiC rectifying section operated at 1 atm while the HIDiC stripping section having an overhead condenser is depressurized below 300 mmHg by a vacuum pump. When an internal heat integration was made between these rectifying and stripping sections, it brings about a great energy saving effect > 50%. Its enriched HIDiC overhead product (around 93 wt% ethanol) is further dehydrated up to > 99.5 wt% ethanol by the next azeotropic distillation using c-hexane as an entrainer. The first column with a decanter (azeotropic column) is operated at 1 atm while the second column (water column) is pressurized at 2 atm, so that the hea...
The objective of this study is to model the transport phenomena in packed column distillation wit... more The objective of this study is to model the transport phenomena in packed column distillation with the aid of experiment and computer-aided process simulation. The main concept is in that local distillation efficiency HETP is considered as the height of control volume for shell balance of mass and enthalpy, so that it becomes possible to bridge between the ideal and real processes. Distillation experiment was conducted under the total-reflux condition. Determination of local HETPs was performed by comparing the vertical temperature distribution experimentally observed with the stage-by-stage temperature distribution calculated by computer process simulation. In a manner similar to the analogy analysis of a single-phase boundary layer flow over a flat plate, a semi-empirical model of local similarity between simultaneous interphase mass and enthalpy transfer was successfully built by experiment collaborating with a computer-aided process simulation.
Journal of the Society of Mechanical Engineers, 1990
AIChE Journal, 1981
The rate of exchange of fluid elements between Taylor vortices was experimentally determined for ... more The rate of exchange of fluid elements between Taylor vortices was experimentally determined for low axial flow rates. A model was formulated defining the exchange coefficient appropriate for this flow system. In the laminar vortex flow region, the measured exchange coefficient increases with Re but is almost independent of Ta. SCOPE The tangential annular flow between two coaxial cylinders has a transition from the purely laminar to the laminar Taylor vortex flow when the revolution of the inner cylinder exceeds a critical value. If a small axial flow is independently added to this laminar vortex motion, each vortex pair marches through the annulus in single file holding its original shape. The toroidal motion of fluid elements within vortices causes effective radial mixing whereas the cell boundaries prevent fluid elements from being exchanged between vortices, especially when the axial flow rate is small. Each pair of vortices can be considered as a well-mixed batch vessel moving through the annulus with the same residence time. The flow system has the possibility of a locally well-mixed, plug-flow reactor required for slow liquid reactions. The exchange coefficient at the cell boundaries is defined to establish a new model appropriate for this Row system and measured by salt-solution tracer technique. CONCLUSIONS AND SIGNIFICANCE There exists a small degree of exchange of fluid elements between pairs of Taylor vortices. The exchange coefficient at the cell boundaries has been defined to establish a new model. The measured exchange coefficient was found to be almost independent of the rotating speed of the inner cylinder and has been correlated by Sh, = 3.7 x 10' Re'.' in the range 0 < Re < 35 and 220 < Ta < 660. The exchange coefficient decreases with decreasing axial flow rate; the flow system approaches a desired plug-flow, whose fluid elements are locally well-mixed but have very narrow residence time distribution.
KAGAKU KOGAKU RONBUNSHU, 1994
Theoretical and applied mechanics Japan, 2002
Proceeding of International Heat Transfer Conference 9, 1990
Journal of Chemical Engineering of Japan, 2004
ABSTRACT
Industrial & Engineering Chemistry Research, Aug 18, 2001
This paper presented a non-steady-state operation for controlling latex particle size distributio... more This paper presented a non-steady-state operation for controlling latex particle size distribution by using continuous emulsion polymerization of vinyl acetate. The experiment was conducted in a CSTR under conditions below the critical micelle concentration of the emulsifier. The monomer conversion attained in the time-independent steady-state operation showed a dramatic rise from nearly 0 to over 60% at the mean residence time of the continuously stirred tank reactor (CSTR), τ c) 22 min. The mean residence time was switched alternately between two values in the non-steady-state operation, one giving zero monomer conversion and the other a high monomer conversion in the usual steady-state operation. The periodic-switching operation induced oscillations in monomer conversion in time. When the switching interval was sufficiently long as compared with the mean residence time, the particle size distribution (PSD) varied synchronously with the switching operation. The present work showed the possibility of controlling the temporal PSD by adjusting the frequency and/or the amplitude of the temporal variation of the mean residence time.
Journal of Fluids and Structures, Apr 1, 2005
The stability of the helical flow in a system of coaxial rotating conical cylinders, the inner on... more The stability of the helical flow in a system of coaxial rotating conical cylinders, the inner one rotating and the outer one stationary was experimentally investigated. The helical flow resulted from a Hopf bifurcation, which occurred only when the acceleration of the inner conical cylinder was smaller than 0.06 rad/s 2. When the rotational speed of the inner conical cylinder was increased, the transition to turbulence occurred following a succession of flow states: (i) threedimensional laminar flow (TDLF), (ii) laminar periodic helical flow (LPHF), (iii) doubly periodic wavy helical flow (DWHF), (iv) weakly turbulent helical flow (WTHF) and (v) fully turbulent helical flow (FTHF). Time series obtained by an electrochemical method permitted the identification and analysis of the fundamental frequencies and their evolutions associated with each time-dependent flow state, using Fourier and wavelet transforms. Phase space analysis revealed the associated attractors constructed from the embedded time series. In the FTHF flow state, the fundamental frequency of the helical flow was observed to have a ratio to the rotational frequency of almost twice that of the one measured in the LPHF regime.
Laser Techniques Applied to Fluid Mechanics, 2000
Tbe purpose of the experimental work is to elucidate the mechanism for the occurrence of chaos in... more Tbe purpose of the experimental work is to elucidate the mechanism for the occurrence of chaos in a Taylor-Couette flow system. Tbe attention was focused on the higher instability region from the doubly-periodic to the weaklyturbulent wavy vortex flow. In order to take note of the effect of hysteresis, the inner cylinder rotation was accelerated at a constant rate from rest until a specified Reynolds number was reached. Tbe test section with the radius ratio of 0.625 had an annular gap width of 22.5 mm and an aspect ratio of 4. A fiberoptic laserDoppler velocimeter was employed to observe a time-dependent, peripheral component of velocity at the central region of vortex ceHs. At the same time, timedependent peripheral component of velo city gradients on the wall of the stationary outer cylinder were measured in the neighborhood of one of the outflow ceH boundaries with a hot-film shear sensor embedded flush with the inside cylindrical surface. Four vortex ceHs were always formed regardless of the acceleration rate of the inner cylinder rotation tested in the start-up operation, but the axial wavelength of the two central vortices was shorter than that of the remaining two end vortices. The amplitudes of the fluctuations of velocity and velocity-gradient varied irregularly whereas the first fundamental frequency was maintained in proportion to the inner cylinder rotation as long as the azimuthaIly-traveling waves existed. It has been conc1uded that chaos occurs firstly at the inflow cell boundaries as a result of instabiIity in the viscous interaction of end vortices with the fixed bottom and top surfaces and that the chaotic turbulence is propagated along the secondary flow streamlines toward the central vortices and penetrated very slowly toward the center of vortex cells.
Journal of Chemical Engineering of Japan, 2008
This is an experimental and analytical report of the second-phase national research project of en... more This is an experimental and analytical report of the second-phase national research project of energy-saving heat integrated distillation column (HIDiC) technology applied to multi-component hydrocarbon distillation processes downstream of the naphtha cracking process. The first column of an existent commercial-scale distillation plant extracting cyclopentane from multi-component hydrocarbon mixtures was selected as the model column of the HIDiC project. The actual operation data were employed not only for the specification of distillation system design but also for the energy-saving analysis. A commercial-scale HIDiC pilot plant has been constructed based on the computer-aided HIDiC design of system and operation. A comparison of the test operation data was made with the computer simulation taking into account the power consumption of the compressor installed between the rectifying and stripping sections. It has been confirmed that the energy conservation level better than the design specification can be attained by means of the actual internal heat integration of the HIDiC pilot plant. The target of energy saving more than 50% of the energy consumption of the existent conventional distillation column (model column) was achieved in various operation conditions. The energy saving higher than 76% was achieved under the condition when the external reflux ratio was reduced to zero. The stable continuous HIDiC operation for 1,000 hr has successfully been realized by the pilot plant.
Theoretical and applied mechanics Japan, 2002
Proceedings of thermal engineering conference, 2001
The purpose qf thr present work is to investigate the transition from periodic to chaotic flows i... more The purpose qf thr present work is to investigate the transition from periodic to chaotic flows in Taylor vortex flow with the aid of a wavelet analysis ． Time series data of fl ロctuating tangential velocity were obta 血 ed with afiberoptic laser −DDppler velocimeter ． To c］ arjfy the dependence of time − fluc 加 ation flow properties on spatial location ， the velocity was measured at several positions with each ' vo 煙 ex ． Ih order to estimate wavelet cor 爬 lation pattems ， logarithmic expectation and information entropy were calculated at each time scale ． コhe wave 】 et paロ ems
International Journal of Heat and Mass Transfer, 1987
The mechanism for the enhancement of stagnation-point heat transfer was explored analyzing the la... more The mechanism for the enhancement of stagnation-point heat transfer was explored analyzing the large-scale turbulent structures of an impinging round jet by a statistical technique with conditional sampling. It has been found that large-scale eddies impinging on the heat transfer surfaces produce a turbulent surface-renewal effect dominant for the enhancement of the jet impingement heat transfer. The effect of heat transfer enhancement can be described in terms of the turbulent Reynolds and Strouhal numbers based on the characteristic turbulence intensity and frequency of the large-scale eddies impinging on the stagnation-point boundary layer.
Proceeding of International Heat Transfer Conference 8, 1986
ABSTRACT
A fermented mash liquid (3,000 kg/h, 5 wt% ethanol) is firstly enriched up to near-azeotropic poi... more A fermented mash liquid (3,000 kg/h, 5 wt% ethanol) is firstly enriched up to near-azeotropic point by using a compressor-free HIDiC (Heat Integrated Distillation Column) system developed by our NEDO project. This system consists of a mash column followed by a double-tube HIDiC trayed column. The mash column operated at 1 atm supplies vapour into the bottom of HIDiC rectifying section operated at 1 atm while the HIDiC stripping section having an overhead condenser is depressurized below 300 mmHg by a vacuum pump. When an internal heat integration was made between these rectifying and stripping sections, it brings about a great energy saving effect > 50%. Its enriched HIDiC overhead product (around 93 wt% ethanol) is further dehydrated up to > 99.5 wt% ethanol by the next azeotropic distillation using c-hexane as an entrainer. The first column with a decanter (azeotropic column) is operated at 1 atm while the second column (water column) is pressurized at 2 atm, so that the hea...
The objective of this study is to model the transport phenomena in packed column distillation wit... more The objective of this study is to model the transport phenomena in packed column distillation with the aid of experiment and computer-aided process simulation. The main concept is in that local distillation efficiency HETP is considered as the height of control volume for shell balance of mass and enthalpy, so that it becomes possible to bridge between the ideal and real processes. Distillation experiment was conducted under the total-reflux condition. Determination of local HETPs was performed by comparing the vertical temperature distribution experimentally observed with the stage-by-stage temperature distribution calculated by computer process simulation. In a manner similar to the analogy analysis of a single-phase boundary layer flow over a flat plate, a semi-empirical model of local similarity between simultaneous interphase mass and enthalpy transfer was successfully built by experiment collaborating with a computer-aided process simulation.
Journal of the Society of Mechanical Engineers, 1990
AIChE Journal, 1981
The rate of exchange of fluid elements between Taylor vortices was experimentally determined for ... more The rate of exchange of fluid elements between Taylor vortices was experimentally determined for low axial flow rates. A model was formulated defining the exchange coefficient appropriate for this flow system. In the laminar vortex flow region, the measured exchange coefficient increases with Re but is almost independent of Ta. SCOPE The tangential annular flow between two coaxial cylinders has a transition from the purely laminar to the laminar Taylor vortex flow when the revolution of the inner cylinder exceeds a critical value. If a small axial flow is independently added to this laminar vortex motion, each vortex pair marches through the annulus in single file holding its original shape. The toroidal motion of fluid elements within vortices causes effective radial mixing whereas the cell boundaries prevent fluid elements from being exchanged between vortices, especially when the axial flow rate is small. Each pair of vortices can be considered as a well-mixed batch vessel moving through the annulus with the same residence time. The flow system has the possibility of a locally well-mixed, plug-flow reactor required for slow liquid reactions. The exchange coefficient at the cell boundaries is defined to establish a new model appropriate for this Row system and measured by salt-solution tracer technique. CONCLUSIONS AND SIGNIFICANCE There exists a small degree of exchange of fluid elements between pairs of Taylor vortices. The exchange coefficient at the cell boundaries has been defined to establish a new model. The measured exchange coefficient was found to be almost independent of the rotating speed of the inner cylinder and has been correlated by Sh, = 3.7 x 10' Re'.' in the range 0 < Re < 35 and 220 < Ta < 660. The exchange coefficient decreases with decreasing axial flow rate; the flow system approaches a desired plug-flow, whose fluid elements are locally well-mixed but have very narrow residence time distribution.
KAGAKU KOGAKU RONBUNSHU, 1994
Theoretical and applied mechanics Japan, 2002
Proceeding of International Heat Transfer Conference 9, 1990