This chapter discusses design of shell and tube exchanger with particular reference to TEMA and I... more This chapter discusses design of shell and tube exchanger with particular reference to TEMA and IS 4503 design codes. Prior to design, different components of a typical exchanger, criteria for selection of exchanger type and number of passes as well as considerations for mechanical and process design are discussed. Exchanger specification sheet for input process data and design summary as per TEMA are provided. The stepwise procedure for process design using FT method is detailed and estimation of different pressure drop components is included. This is followed by mechanical detailing of shell and tube, channel cover, segmental and impingement baffle, nozzles, exchanger support and exchanger material. Tables of standard dimensions for different exchanger components are included in this chapter and also as Appendix for the convenience of the designer. The procedure outlined and the relevant discussions are illustrated by a design problem at the end.
This study explores the physics of laminar planar hydraulic jump of power-law liquids in a horizo... more This study explores the physics of laminar planar hydraulic jump of power-law liquids in a horizontal channel through shallow water analysis. The theory is supplemented and validated by numerical simulation performed by the phase-field method in COMSOL Multiphysics. The analysis is applicable for shear thinning as well as thickening liquids and reduces to Newtonian equations when the flow behavior index (n) is unity. The analytical and numerical results are further validated with experimental data of the present study. The steady state free surface profile in conjunction with a modified Bélanger type equation predicts jump location and strength (the ratio of film height just after and before the jump). The analysis provides a modified scaled relationship between the jump location and the liquid flow rate compared to that proposed for inviscid and viscous Newtonian liquids. An order of magnitude analysis expresses the scaled jump location and strength as a function of inlet Reynolds ...
Abstract This chapter presents the design procedure and examples of tower internals for gas–liqui... more Abstract This chapter presents the design procedure and examples of tower internals for gas–liquid and vapour–liquid contacting towers. The criteria for selection of tower type and tray type are discussed. In each case, estimation of tower diameter and height is elaborated. The design aspects including range of operation, tray layout and downcomer dynamics along with different head losses and check for limiting conditions are discussed separately for bubble cap, sieve plate and valve tray towers. Each design procedure is illustrated with examples at the end of this chapter. This chapter concludes with discussions on designing chimney trays and draw off boxes, feed tray and reflux entry arrangement on top tray and tower bottom arrangement.
Abstract The chapter deals with the design of absorption and stripping columns, covering both tra... more Abstract The chapter deals with the design of absorption and stripping columns, covering both tray and packed type. For tray columns, the graphical procedure to estimate the number of contacting stages is discussed, and the concept of operating line, equilibrium curve, and absorption factor is introduced. For packed columns, the design based on the mass transfer coefficient is elaborated to estimate bed height from HTU, NTU, and HETP. The estimation procedure for minimum liquid absorbent or stripping gas flow requirement and the simplified expressions for dilute solutions are provided. The concept of enhancement factor for absorption with chemical reaction is also discussed. The Chapter concludes with two design examples illustrating the difference in consideration for dilute and concentrated systems in packed column absorber.
The chapter presents a detailed discussion on plant utilities, namely, steam at different levels,... more The chapter presents a detailed discussion on plant utilities, namely, steam at different levels, compressed air, including plant air, and instrumentation air, electrical power, commonly used inert gases and different quality water streams like firewater, demineralized water and boiler feed water. The importance of steam as a hot utility and a typical steam generation and consumption network, the specific uses, and production routes of common inert gases and specifications, and uses of different quality water streams in process plants are covered. The need for proper planning of utility utilization at the design stage is emphasized. Detailed design of a compressed air supply stream is illustrated, and the design of a fuel system is elaborated. The chapter concludes with good design practices for efficient utility systems.
We reformulate shallow water theory to understand viscous shear induced natural hydraulic jumps i... more We reformulate shallow water theory to understand viscous shear induced natural hydraulic jumps in channels slightly deviated from the horizontal. One of the interesting contributions of the study is a modified expression for Froude number to predict jumps in inclined channels. The proposed Froude number is different from the conventional expression which incorporates channel inclination as a straight forward component of gravity. This highlights the complexity that a jump can generate even in single phase laminar flow. We also obtain an analytical expression for predicting jump strength and show that the scaling relationship originally proposed for jump location in horizontal channels is applicable for both upslope and downslope flows. As expected, upslope flow aids jump formation and beyond a critical adverse tilt, a submerged jump results in subcritical flow right from the entry. On the other hand, both Reynolds number and channel tilt suppress the tendency to jump in downslope flows and below a critical downslope inclination, the flow remains supercritical throughout the channel length. The film thickness for fully developed flow can be predicted from the exact solution of the Navier–Stokes equations. As the theory encounters a singularity in the jump region, numerical simulations and experimental results have been used to obtain additional insights into the physics of jump formation. They have revealed the existence of submerged jump, wavy jump, smooth jump and no jump conditions as a function of liquid Reynolds number, scaled channel length and channel inclination. Such a variety of jump geometries in planar laminar flow has not been reported earlier. Both theory and simulations also reveal that the linear free surface profile upstream of the jump is a function of Reynolds number only, while the downstream profiles can be tuned by changing both Reynolds number as well as the channel length and tilt over the range of parameters studied. We thus demonstrate that, despite the simplicity and the approximations involved, shallow water equations formulated assuming self-similar velocity profiles can elucidate the physics of planar laminar jumps over slight inclinations, difficult to avoid in practice. The analytical and simulated results have been extensively validated with experimental data obtained from a specially designed test rig which ensures laminar flow before and after the jump. To the authors’ knowledge, almost no experimental study has to date been reported on films ‘thin enough’ to remain laminar even after the planar jump.
Material flow in a rectangular quasi-two-dimensional silo discharging simultaneously through two ... more Material flow in a rectangular quasi-two-dimensional silo discharging simultaneously through two orifices has been investigated. A number of variations of the proximity of the sidewall of the silo with an individual orifice and the distance between the two orifices have been tried. It has been observed that beyond a certain distance between the two orifices, a neutral axis parallel to the axes of the orifices can be identified. The neutral axis divides the flow field in the silo between two non-interfering zones each of which is created due to the flow through a single orifice. Flow field created by a single orifice on the other hand depends on its proximity to the sidewall. Based on the above observation, an extension of the kinematic model for material discharge through a single orifice has been extended for predicting the velocity field during simultaneous discharge through two orifices. Based on the distance between two orifices, the limitation of this model has also been predicted.
The phenomenon of draining, although ubiquitous in nature, has received scant attention especiall... more The phenomenon of draining, although ubiquitous in nature, has received scant attention especially in the meso-scale. We observe that closed top tubes drain by the inception of an axisymmetric 'Taylor finger' while a minute pierce of the top closure results in an altogether different physics with air entry from the top pushing the liquid out. Again, a coupled mechanism comprising full bore followed by film draining is observed for "too small" a top pierce at "high enough" Eotvos number. Top pierce initiates draining in dimensions which would not drain otherwise and finger entry hastens the process of draining. The myriad of phenomena thus exhibited is depicted as phase diagrams in vertical and inclined conduits. A mechanistic model has been proposed to predict draining and the onset of finger entry in vertical tubes.
This chapter discusses design of shell and tube exchanger with particular reference to TEMA and I... more This chapter discusses design of shell and tube exchanger with particular reference to TEMA and IS 4503 design codes. Prior to design, different components of a typical exchanger, criteria for selection of exchanger type and number of passes as well as considerations for mechanical and process design are discussed. Exchanger specification sheet for input process data and design summary as per TEMA are provided. The stepwise procedure for process design using FT method is detailed and estimation of different pressure drop components is included. This is followed by mechanical detailing of shell and tube, channel cover, segmental and impingement baffle, nozzles, exchanger support and exchanger material. Tables of standard dimensions for different exchanger components are included in this chapter and also as Appendix for the convenience of the designer. The procedure outlined and the relevant discussions are illustrated by a design problem at the end.
This study explores the physics of laminar planar hydraulic jump of power-law liquids in a horizo... more This study explores the physics of laminar planar hydraulic jump of power-law liquids in a horizontal channel through shallow water analysis. The theory is supplemented and validated by numerical simulation performed by the phase-field method in COMSOL Multiphysics. The analysis is applicable for shear thinning as well as thickening liquids and reduces to Newtonian equations when the flow behavior index (n) is unity. The analytical and numerical results are further validated with experimental data of the present study. The steady state free surface profile in conjunction with a modified Bélanger type equation predicts jump location and strength (the ratio of film height just after and before the jump). The analysis provides a modified scaled relationship between the jump location and the liquid flow rate compared to that proposed for inviscid and viscous Newtonian liquids. An order of magnitude analysis expresses the scaled jump location and strength as a function of inlet Reynolds ...
Abstract This chapter presents the design procedure and examples of tower internals for gas–liqui... more Abstract This chapter presents the design procedure and examples of tower internals for gas–liquid and vapour–liquid contacting towers. The criteria for selection of tower type and tray type are discussed. In each case, estimation of tower diameter and height is elaborated. The design aspects including range of operation, tray layout and downcomer dynamics along with different head losses and check for limiting conditions are discussed separately for bubble cap, sieve plate and valve tray towers. Each design procedure is illustrated with examples at the end of this chapter. This chapter concludes with discussions on designing chimney trays and draw off boxes, feed tray and reflux entry arrangement on top tray and tower bottom arrangement.
Abstract The chapter deals with the design of absorption and stripping columns, covering both tra... more Abstract The chapter deals with the design of absorption and stripping columns, covering both tray and packed type. For tray columns, the graphical procedure to estimate the number of contacting stages is discussed, and the concept of operating line, equilibrium curve, and absorption factor is introduced. For packed columns, the design based on the mass transfer coefficient is elaborated to estimate bed height from HTU, NTU, and HETP. The estimation procedure for minimum liquid absorbent or stripping gas flow requirement and the simplified expressions for dilute solutions are provided. The concept of enhancement factor for absorption with chemical reaction is also discussed. The Chapter concludes with two design examples illustrating the difference in consideration for dilute and concentrated systems in packed column absorber.
The chapter presents a detailed discussion on plant utilities, namely, steam at different levels,... more The chapter presents a detailed discussion on plant utilities, namely, steam at different levels, compressed air, including plant air, and instrumentation air, electrical power, commonly used inert gases and different quality water streams like firewater, demineralized water and boiler feed water. The importance of steam as a hot utility and a typical steam generation and consumption network, the specific uses, and production routes of common inert gases and specifications, and uses of different quality water streams in process plants are covered. The need for proper planning of utility utilization at the design stage is emphasized. Detailed design of a compressed air supply stream is illustrated, and the design of a fuel system is elaborated. The chapter concludes with good design practices for efficient utility systems.
We reformulate shallow water theory to understand viscous shear induced natural hydraulic jumps i... more We reformulate shallow water theory to understand viscous shear induced natural hydraulic jumps in channels slightly deviated from the horizontal. One of the interesting contributions of the study is a modified expression for Froude number to predict jumps in inclined channels. The proposed Froude number is different from the conventional expression which incorporates channel inclination as a straight forward component of gravity. This highlights the complexity that a jump can generate even in single phase laminar flow. We also obtain an analytical expression for predicting jump strength and show that the scaling relationship originally proposed for jump location in horizontal channels is applicable for both upslope and downslope flows. As expected, upslope flow aids jump formation and beyond a critical adverse tilt, a submerged jump results in subcritical flow right from the entry. On the other hand, both Reynolds number and channel tilt suppress the tendency to jump in downslope flows and below a critical downslope inclination, the flow remains supercritical throughout the channel length. The film thickness for fully developed flow can be predicted from the exact solution of the Navier–Stokes equations. As the theory encounters a singularity in the jump region, numerical simulations and experimental results have been used to obtain additional insights into the physics of jump formation. They have revealed the existence of submerged jump, wavy jump, smooth jump and no jump conditions as a function of liquid Reynolds number, scaled channel length and channel inclination. Such a variety of jump geometries in planar laminar flow has not been reported earlier. Both theory and simulations also reveal that the linear free surface profile upstream of the jump is a function of Reynolds number only, while the downstream profiles can be tuned by changing both Reynolds number as well as the channel length and tilt over the range of parameters studied. We thus demonstrate that, despite the simplicity and the approximations involved, shallow water equations formulated assuming self-similar velocity profiles can elucidate the physics of planar laminar jumps over slight inclinations, difficult to avoid in practice. The analytical and simulated results have been extensively validated with experimental data obtained from a specially designed test rig which ensures laminar flow before and after the jump. To the authors’ knowledge, almost no experimental study has to date been reported on films ‘thin enough’ to remain laminar even after the planar jump.
Material flow in a rectangular quasi-two-dimensional silo discharging simultaneously through two ... more Material flow in a rectangular quasi-two-dimensional silo discharging simultaneously through two orifices has been investigated. A number of variations of the proximity of the sidewall of the silo with an individual orifice and the distance between the two orifices have been tried. It has been observed that beyond a certain distance between the two orifices, a neutral axis parallel to the axes of the orifices can be identified. The neutral axis divides the flow field in the silo between two non-interfering zones each of which is created due to the flow through a single orifice. Flow field created by a single orifice on the other hand depends on its proximity to the sidewall. Based on the above observation, an extension of the kinematic model for material discharge through a single orifice has been extended for predicting the velocity field during simultaneous discharge through two orifices. Based on the distance between two orifices, the limitation of this model has also been predicted.
The phenomenon of draining, although ubiquitous in nature, has received scant attention especiall... more The phenomenon of draining, although ubiquitous in nature, has received scant attention especially in the meso-scale. We observe that closed top tubes drain by the inception of an axisymmetric 'Taylor finger' while a minute pierce of the top closure results in an altogether different physics with air entry from the top pushing the liquid out. Again, a coupled mechanism comprising full bore followed by film draining is observed for "too small" a top pierce at "high enough" Eotvos number. Top pierce initiates draining in dimensions which would not drain otherwise and finger entry hastens the process of draining. The myriad of phenomena thus exhibited is depicted as phase diagrams in vertical and inclined conduits. A mechanistic model has been proposed to predict draining and the onset of finger entry in vertical tubes.
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