Satyajit Sahu - Academia.edu (original) (raw)
Papers by Satyajit Sahu
Materials Today: Proceedings, 2018
In the present work, effect of addition of Copper powder in the dielectric media during electro-d... more In the present work, effect of addition of Copper powder in the dielectric media during electro-discharge machining of Inconel 718 has been attempted. Since, traditional machining routes are inappropriate for 'difficult-to-cut' materials (like Inconel 718 super alloys); EDM process has been adapted. In contrast to conventional EDM (no powder); addition of conductive powder particles into the dielectric media has been recommended in literature in order to improve machinability of super alloys. Experiments have been performed by varying peak discharge current and pulse duration; Copper powder (400 Mesh) has been added to the EDM oil (dielectric media). Performance of powder-mixed EDM has been analyzed in terms of material removal efficiency, surface roughness, surface crack density and white layer thickness. EDS and XRD tests have been carried out to understand chemical composition and metallurgical aspects of the machined surface (viz. material migration, phase, extent of grain refinement, formation of intermetallic compounds, residual stress) as compared to 'as received' parent material.
Chemical Engineering and Processing - Process Intensification, 2018
Present investigation reports the effect of helical surface disc turbulators (HSDTs) on heat tran... more Present investigation reports the effect of helical surface disc turbulators (HSDTs) on heat transfer and pressure drop characteristics in double pipe heat exchanger (DPHE). HSDTs has been utilized in the annulus region. Tests are conducted by insertion of HSDTs with various operating parameters including three different diameter ratios (DR= do/Di = 0.42, 0.475 and 0.54), three different helix angles (ɸ = 20 o , 30 o and 40 o) and varied range of Reynolds Number (3500-10500). Water, used as hot fluid, flows in the inner tube, while air, used as cold fluid, flows through the annulus. The tests are conducted for air for uniform wall temperature condition. The heat exchanger with least diameter ratio and increased helix angle is found to exhibit the highest Nusselt number and friction factor. Results indicate that maximum enhancement is obtained for smallest diameter ratio (DR = 0.42) and helix angle (ɸ = 40 o). The thermal performance factor is found to be greater than unity for each configuration studied with DPHE using HSDTs. Correlations have been developed Nusselt number, friction factor and thermal performance factor for Reynolds number varying between 3500-10500.
Volume 3: Thermal-Hydraulics, 2016
Impinging jet surface cooling is being used in many industrial and engineering applications due t... more Impinging jet surface cooling is being used in many industrial and engineering applications due to their higher heat removal rate. Jet impingement is one of the methods to cool hot surfaces, especially in textile, metal and electronic industries. Due to high heat removal rate the jet impingement cooling of the hot surfaces is being used in nuclear industries. During the loss of coolant accidents (LOCA) in nuclear power plant, an emergency core cooling system (ECCS) cool the cluster of clad tubes using consisting of fuel rods. The usual water flow within a reactor core is bottom to top, parallel to the fuel rods. When a hot surface quenched at very high temperature using a jet of cold fluid, during the quenching the initial heat transfer is limited by film boiling. The effective cooling takes place only after the surface temperature is below the leidenfrost temperature. In the present work an experimental investigation has been carried out to analyze the rewetting phenomenon of a hot...
Lecture Notes in Mechanical Engineering, 2016
In the present study, an experimental investigation has been carried out to analyze the effect of... more In the present study, an experimental investigation has been carried out to analyze the effect of surfactant on heat transfer characteristics of a circular impinging liquid jet. A rectangular stainless steel foil (AISI-304, 0.15 mm thick), used as the target surface, was electrically heated to obtain the required initial temperature. A single-phase circular water jet of diameter 1.38 mm is allowed to impinge on the hot surface. Thermal images of the target surface during liquid jet impingement were recorded by using an infrared camera (A655sc, FLIR System) positioned on the side of the target surface opposite to the impinging nozzle. The distribution of heat flux on the target surface is evaluated from the recorded thermal images during transient cooling. Tests were performed for an initial surface temperature of 500 °C, Reynolds number (8893 ≤ Re ≤ 12847) and nozzle to plate distance was l/d = 2.5. Experiments have been performed using 2-Ethyl Hexanol added water solution at different concentration (0–400 ppm). Surface heat flux distribution during transient cooling of hot surface is obtained. It was observed that the surface heat flux increases with the rise in the jet Reynolds number and achieves its maximum at surfactant concentration of 200 ppm at stagnation point (6.2 MW/m2 at Re = 8893 to 6.5 MW/m2 at Re = 12847; 200 ppm).
Journal of The Institution of Engineers (India): Series C, 2016
This paper reports the hydrodynamically and thermally fully developed, laminar, incompressible, f... more This paper reports the hydrodynamically and thermally fully developed, laminar, incompressible, forced convective heat transfer characteristics of gaseous flows through a parallel plate microchannel with different constant heat flux boundary conditions. The first order velocity slip and viscous dissipation effects are considered in the analysis. Here, three different thermal boundary conditions such as: both plates kept at different constant heat fluxes, both plates kept at equal constant heat fluxes and one plate kept at constant heat flux and other one insulated are considered for the analysis. The deviation in Nusselt number between the model that considers both first order velocity slip and temperature jump and the one that considers only velocity slip is reported. Also, the effect of various heat flux ratios on the Nusselt number is reported in this analysis. In addition, the deviation in Nusselt number between first and second order slip model is discussed in this study. Keywords Brinkman number Á Heat flux ratio Á Knudsen number Á Velocity slip Á Viscous dissipation List of Symbols a 1 Parameter defined in Eq. (10) a 2 Parameter defined in Eq. (24) a 3 Parameter defined in Eq. (34) Br q1 Modified Brinkman number, defined in Eq. (9)
This is to certify that the thesis entitled Agility Evaluation in Fuzzy Environment submitted by ... more This is to certify that the thesis entitled Agility Evaluation in Fuzzy Environment submitted by Sri Suraj Kant Sahu has been carried out under my supervision in partial fulfillment of the requirements for the Degree of
Topics in Current Chemistry, 2011
A short introduction to the fundamental features and recent developments of supramolecular chemis... more A short introduction to the fundamental features and recent developments of supramolecular chemistry is presented besides defining scope and limitation of this review article. A brief overview about calix[n]arenes and especially resorcin[4]arenes and their conformationally rigid cavitands is given. Selected examples are presented to demonstrate the dependence of self-assembly of cavitands exhibiting different flexibility either due to their basic macrocycle or due to flexible receptor units commonly located at the o,o'-position of the resorcinarene ring. In addition, the process of self-assembly is also controlled by metal coordination geometry as shown by one example. The receptor units may also be connected at the methylene group of the cavitand as shown by one example. Examples of supramolecular architectures are presented utilizing the special features of 2,2':6',2″-terpyridine (terpy) metal-binding ligand. The synthesis and characterization of a metallo-supramolecular Zn-coordination cage with a diameter of 4-5 nm based on a cavitand-terpy building block is presented in detail.
Journal of Molecular Liquids, 2011
The fluorescence quenching behaviour of naphthols by copper ion has been studied in different con... more The fluorescence quenching behaviour of naphthols by copper ion has been studied in different concentration of anionic sodium lauryl sulphate micelle. Various quenching processes have been analyzed to explain the quenching efficiency. The quenching behaviour of naphthols and naphtholates explained by a biphasic model consisting of two phases i.e.(a) quenching spheres containing the excited fluorophores and the quenchers resulting in transient component (for ROH*) and (b) the bulk phase where quenching is dynamic or diffusional (for RO¯*). The probable number of quenchers present in the quenching sphere of action has been calculated.
![Research paper thumbnail of Supramolecular Capsules Derived from Resorcin[4]arenes by H-Bonding and Metal Coordination: Synthesis, Characterization, and Single-Molecule Force Spectroscopy](https://attachments.academia-assets.com/95468492/thumbnails/1.jpg)
](Israel Journal of Chemistry, 2011
Self-assembly by H-bonding and by metal-coordination of functionalized calix[4]arenes and cavitan... more Self-assembly by H-bonding and by metal-coordination of functionalized calix[4]arenes and cavitands to large supramolecular capsules is described. In addition, a new method of analyzing supramolecular recognition processes at the single molecule level is discussed. By measuring interaction forces in a hydrogen-bonded assembly using single-molecule force spectroscopy (SMFS), the dynamics of the self-assembly process can be evaluated. In the future, consequent application of this new technique will influence supramolecular design principles and the use of non-covalent interactions as construction elements in the field of nanotechnology.
Indian Journal of Chemistry, 2008
Materials Today: Proceedings, 2018
In the present work, effect of addition of Copper powder in the dielectric media during electro-d... more In the present work, effect of addition of Copper powder in the dielectric media during electro-discharge machining of Inconel 718 has been attempted. Since, traditional machining routes are inappropriate for 'difficult-to-cut' materials (like Inconel 718 super alloys); EDM process has been adapted. In contrast to conventional EDM (no powder); addition of conductive powder particles into the dielectric media has been recommended in literature in order to improve machinability of super alloys. Experiments have been performed by varying peak discharge current and pulse duration; Copper powder (400 Mesh) has been added to the EDM oil (dielectric media). Performance of powder-mixed EDM has been analyzed in terms of material removal efficiency, surface roughness, surface crack density and white layer thickness. EDS and XRD tests have been carried out to understand chemical composition and metallurgical aspects of the machined surface (viz. material migration, phase, extent of grain refinement, formation of intermetallic compounds, residual stress) as compared to 'as received' parent material.
Chemical Engineering and Processing - Process Intensification, 2018
Present investigation reports the effect of helical surface disc turbulators (HSDTs) on heat tran... more Present investigation reports the effect of helical surface disc turbulators (HSDTs) on heat transfer and pressure drop characteristics in double pipe heat exchanger (DPHE). HSDTs has been utilized in the annulus region. Tests are conducted by insertion of HSDTs with various operating parameters including three different diameter ratios (DR= do/Di = 0.42, 0.475 and 0.54), three different helix angles (ɸ = 20 o , 30 o and 40 o) and varied range of Reynolds Number (3500-10500). Water, used as hot fluid, flows in the inner tube, while air, used as cold fluid, flows through the annulus. The tests are conducted for air for uniform wall temperature condition. The heat exchanger with least diameter ratio and increased helix angle is found to exhibit the highest Nusselt number and friction factor. Results indicate that maximum enhancement is obtained for smallest diameter ratio (DR = 0.42) and helix angle (ɸ = 40 o). The thermal performance factor is found to be greater than unity for each configuration studied with DPHE using HSDTs. Correlations have been developed Nusselt number, friction factor and thermal performance factor for Reynolds number varying between 3500-10500.
Volume 3: Thermal-Hydraulics, 2016
Impinging jet surface cooling is being used in many industrial and engineering applications due t... more Impinging jet surface cooling is being used in many industrial and engineering applications due to their higher heat removal rate. Jet impingement is one of the methods to cool hot surfaces, especially in textile, metal and electronic industries. Due to high heat removal rate the jet impingement cooling of the hot surfaces is being used in nuclear industries. During the loss of coolant accidents (LOCA) in nuclear power plant, an emergency core cooling system (ECCS) cool the cluster of clad tubes using consisting of fuel rods. The usual water flow within a reactor core is bottom to top, parallel to the fuel rods. When a hot surface quenched at very high temperature using a jet of cold fluid, during the quenching the initial heat transfer is limited by film boiling. The effective cooling takes place only after the surface temperature is below the leidenfrost temperature. In the present work an experimental investigation has been carried out to analyze the rewetting phenomenon of a hot...
Lecture Notes in Mechanical Engineering, 2016
In the present study, an experimental investigation has been carried out to analyze the effect of... more In the present study, an experimental investigation has been carried out to analyze the effect of surfactant on heat transfer characteristics of a circular impinging liquid jet. A rectangular stainless steel foil (AISI-304, 0.15 mm thick), used as the target surface, was electrically heated to obtain the required initial temperature. A single-phase circular water jet of diameter 1.38 mm is allowed to impinge on the hot surface. Thermal images of the target surface during liquid jet impingement were recorded by using an infrared camera (A655sc, FLIR System) positioned on the side of the target surface opposite to the impinging nozzle. The distribution of heat flux on the target surface is evaluated from the recorded thermal images during transient cooling. Tests were performed for an initial surface temperature of 500 °C, Reynolds number (8893 ≤ Re ≤ 12847) and nozzle to plate distance was l/d = 2.5. Experiments have been performed using 2-Ethyl Hexanol added water solution at different concentration (0–400 ppm). Surface heat flux distribution during transient cooling of hot surface is obtained. It was observed that the surface heat flux increases with the rise in the jet Reynolds number and achieves its maximum at surfactant concentration of 200 ppm at stagnation point (6.2 MW/m2 at Re = 8893 to 6.5 MW/m2 at Re = 12847; 200 ppm).
Journal of The Institution of Engineers (India): Series C, 2016
This paper reports the hydrodynamically and thermally fully developed, laminar, incompressible, f... more This paper reports the hydrodynamically and thermally fully developed, laminar, incompressible, forced convective heat transfer characteristics of gaseous flows through a parallel plate microchannel with different constant heat flux boundary conditions. The first order velocity slip and viscous dissipation effects are considered in the analysis. Here, three different thermal boundary conditions such as: both plates kept at different constant heat fluxes, both plates kept at equal constant heat fluxes and one plate kept at constant heat flux and other one insulated are considered for the analysis. The deviation in Nusselt number between the model that considers both first order velocity slip and temperature jump and the one that considers only velocity slip is reported. Also, the effect of various heat flux ratios on the Nusselt number is reported in this analysis. In addition, the deviation in Nusselt number between first and second order slip model is discussed in this study. Keywords Brinkman number Á Heat flux ratio Á Knudsen number Á Velocity slip Á Viscous dissipation List of Symbols a 1 Parameter defined in Eq. (10) a 2 Parameter defined in Eq. (24) a 3 Parameter defined in Eq. (34) Br q1 Modified Brinkman number, defined in Eq. (9)
This is to certify that the thesis entitled Agility Evaluation in Fuzzy Environment submitted by ... more This is to certify that the thesis entitled Agility Evaluation in Fuzzy Environment submitted by Sri Suraj Kant Sahu has been carried out under my supervision in partial fulfillment of the requirements for the Degree of
Topics in Current Chemistry, 2011
A short introduction to the fundamental features and recent developments of supramolecular chemis... more A short introduction to the fundamental features and recent developments of supramolecular chemistry is presented besides defining scope and limitation of this review article. A brief overview about calix[n]arenes and especially resorcin[4]arenes and their conformationally rigid cavitands is given. Selected examples are presented to demonstrate the dependence of self-assembly of cavitands exhibiting different flexibility either due to their basic macrocycle or due to flexible receptor units commonly located at the o,o'-position of the resorcinarene ring. In addition, the process of self-assembly is also controlled by metal coordination geometry as shown by one example. The receptor units may also be connected at the methylene group of the cavitand as shown by one example. Examples of supramolecular architectures are presented utilizing the special features of 2,2':6',2″-terpyridine (terpy) metal-binding ligand. The synthesis and characterization of a metallo-supramolecular Zn-coordination cage with a diameter of 4-5 nm based on a cavitand-terpy building block is presented in detail.
Journal of Molecular Liquids, 2011
The fluorescence quenching behaviour of naphthols by copper ion has been studied in different con... more The fluorescence quenching behaviour of naphthols by copper ion has been studied in different concentration of anionic sodium lauryl sulphate micelle. Various quenching processes have been analyzed to explain the quenching efficiency. The quenching behaviour of naphthols and naphtholates explained by a biphasic model consisting of two phases i.e.(a) quenching spheres containing the excited fluorophores and the quenchers resulting in transient component (for ROH*) and (b) the bulk phase where quenching is dynamic or diffusional (for RO¯*). The probable number of quenchers present in the quenching sphere of action has been calculated.
Israel Journal of Chemistry, 2011
Self-assembly by H-bonding and by metal-coordination of functionalized calix[4]arenes and cavitan... more Self-assembly by H-bonding and by metal-coordination of functionalized calix[4]arenes and cavitands to large supramolecular capsules is described. In addition, a new method of analyzing supramolecular recognition processes at the single molecule level is discussed. By measuring interaction forces in a hydrogen-bonded assembly using single-molecule force spectroscopy (SMFS), the dynamics of the self-assembly process can be evaluated. In the future, consequent application of this new technique will influence supramolecular design principles and the use of non-covalent interactions as construction elements in the field of nanotechnology.
Indian Journal of Chemistry, 2008