Department of Mechanical engineering
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Item Numerical simulation of Laminar flow heat transfer Enhancement in a three-dimensional Channel flow with Inclined ribs(Cyber Times International Journal of Technology & Management, 2014-09) Bhattacharyya, SuvanjanEffects of ribs on forced convection heat transfer and friction loss behaviors for laminar airflow through a constant heat flux channel are numerically investigated in the present work. Ribs are known to enhance the heat transfer between the energy-carrying fluid and the heat transfer surfaces. A numerical investigation on the laminar flow and heat transfer behavior in the circular channel with inclined ribs for three different. The computations based on the finite volume method with the SIMPLE algorithm have been carried out with Reynolds number ranging from 100 to 1000. The numerical results show that the heat transfer of the inclined ribbed channel are improved about 90-110% compared with smooth duct because co-rotating vortices are generated on the cross section of channel. In addition, the effects of geometric parameters for ribs on the heat transfer, such as rib height, rib pitch, were analyzed. The heat transfer, pressure loss and thermal performance of the inclined ribs with different attack angles (θ) of 0o, 10o, 15o, 20o, 25o, and 90oare examined.Item 3d computational study of fluid flow and heat transfer in a dimple enhancer channel(Begell House, 2017) Bhattacharyya, SuvanjanHeat transfer behaviour in dimple enhancer channel swirl generator is investigated numerically. Vortex generator geometry is a widely used procedure for heat transfer improvement. This work presents the investigation of a dimple enhancer channel for turbulent heat transfer with air (Pr 0.707) as the working fluid. In the present paper, transition - SST model which can predict the change of flow regime from laminar through intermittent to turbulent has been used for numerical simulations. The simulation are performed using three dimple ratio (r = d/D = 0.1, 0.15 and 0.2) and three different space ratios (s = y/D = 2.0, 2.5, and 3.0). The computations were conducted with Reynolds number ranging from 100 to 50,000. The results indicate that the large dimple ratio and small space ratio yields a higher heat transfer value with relatively lower performance penalty. The transition from laminar to turbulent regime is observed between Reynolds numbers of 2000 to 3500 for all cases. For all investigated cases the performance factor (η) are almost greater than unity. This result is useful for the design of solar thermal heaters.Item Heat Transfer and Fluid Flow behaviours of a Square Twisted Micro-Channel(IIT Bombay, 2018-12) Bhattacharyya, SuvanjanThe heat transfer and pressure drop analysis of twisted square micro-channel is studied numerically for Reynolds number (Re) ranging from 10 to 250. The laminar flow model is used for formulation in Ansys fluent 15.0, since the flow is laminar. The governing equations are solved with a finite-volume-based numerical method. A three-dimensional non uniform grid was generated, in order to critically examine the flow and heat transfer. The effects of aspect ratio and twist ratio on the Nusselt number and friction factor are investigated. It is found that the twisted geometry of the channel evidently enhance heat transfer by generating longitudinal vortices, which strengthen flow mixing. Such small vortices also upsurge the turbulent kinetic energy (TKE) and decrease thickness of the boundary layer, which lowers local temperature nearby the target surface. Computational results show that the simulation with twisted micro-channel geometry considerably better than the case with straight micro-channel with respect to heat transfer performance.Item Simulation of two-phase nanofluid flow and heat transfer in a 3D diamond shape cavity equipped with square shaped obstacle and decreasing dimensions(Authero, 2020-03) Bhattacharyya, SuvanjanThe present study investigates numerically symmetry simulation of two-phase nanofluid flow and heat transfer in a 3D diamond shape cavity equipped with square-shaped obstacle and decreasing dimensions. The studied material in the present study is assumed with two different emissivity values, ԑ = 0.3 and ԑ = 0.9, due to analyze the effects of emissivity values on radiation heat transfer. Also two different Rayleigh numbers, Ra=106 and 108. The heat transfer fluid is water-based Cu nanofluid which makes a Newtonian nanofluid, but other base fluid is also analyzed. The main aim of present work is to simulate the 3D diamond shape cavity equipped with square-shaped obstacle and decreasing dimensions geometry using symmetry method and also investigate the effects of different Rayleigh numbers, emissivity values and different nanoparticles volume concentrations on thermal and hydraulic characteristics of the model. Base on obtained results, by an increase of nanoparticles volume concentration the temperature gradients and heat transfer characteristics are improved but the streamlines have not a significant change and by an increase of nanoparticles volume concentration the temperature gradients and heat transfer characteristics are improved, but the streamlines have not a significant change. According to results at higher Rayleigh numbers, the heat transfer characteristics are enhanced. Also, it is found that higher Rayleigh numbers and nanoparticles volume concentrations lead to more heat transfer inside the cavity and changes in emissivity coefficients have not a significant effect on heat transfer characteristics and nanofluid flow in the cavity.Item Experimental and Numerical Investigation of the Heat Transfer Characteristics of Laminar Flow in a Vertical Circular Tube at Low Reynolds Numbers(Springer, 2021-06) Bhattacharyya, SuvanjanLaminar flow is very common in practical situations and vertical tubes are used for many industrial applications ranging from cooling of thermal systems such as compact heat exchangers, solar energy collectors, boilers, and nuclear reactor.Item Research Article Investigation of Counterflow Microchannel Heat Exchanger with Hybrid Nanoparticles and PCM Suspension as a Coolant(MDPI, 2021-03) Bhattacharyya, SuvanjanA circular tube fitted with novel corrugated spring tape inserts has been investigated. Air was used as the working fluid. A thorough literature review has been done and this geometry has not been studied previously, neither experimentally nor theoretically. A novel experimental investigation of this enhanced geometry can, therefore, be treated as a new substantial contribution in the open literature. Three different spring ratio and depth ratio has been used in this study. Increase in thermal energy transport coefficient is noticed with increase in depth ratio. Corrugated spring tape shows promising results towards heat transfer enhancement. This geometry performs significantly better (60% to 75% increase in heat duty at constant pumping power and 20% to 31% reduction in pumping power at constant heat duty) than simple spring tape. This paper also presented a statistical analysis of the heat transfer and fluid flow by developing an artificial neural network (ANN)- based machine learning (ML) model. The model is evaluated to have an accuracy of 98.00% on unknown test data. These models will help the researchers working in heat transfer enhancementbased experiments to understand and predict the output. As a result, the time and cost of the experiments will reduce. The results of this investigation can be used in designing heat exchangersItem Computational Investigation on Flow Dynamics and Heat Transfer of Nanofluid in Low Reynolds Number Under Magnetic Field(Springer, 2023-04) Bhattacharyya, SuvanjanThe effect of magnetic field on the heat transfer enhancement and pressure drop is studied numerically. A water based Fe3O4 nanofluid (2 Vol%) is flowing in a 2-dimensional heated channel at low Reynold’s number (Re = 150 - 250) and different magnetic field intensities ranging from 1200 G to 2000 G are applied. The heat sink with dimensions of 40 mm (L) X 4 mm (H) consists of magnets placed at four different locations. The magnetic field is acting as a vortex generator which enhance heat transfer for highly concentrated heat fluxes. The heat transfer enhancement due to the magnetic field at x = 25 mm is studied. Results showed that there is an improvement of maximum 26% in heat transfer using magnetic nano fluid with magnetic field as compared to pure water. This value grows to around 35% when a magnetic field of strength 1200G is applied and even around 200% at magnetic field of strength 4000G as compared to pure water. However, this enhancement comes with an increase of pressure drop and back flow. This can be explained due to formation of vortices due to the turbulence caused by the sudden force of magnetic field. The optimum condition is obtained at magnetic field of strength 2000 G with a heat transfer enhancement of around 70%.Item Numerical Analysis of Heat Transfer and Pressure Drop in a Square Channel with Novel Centre Hole Inclined Ribs(Springer, 2023-04) Bhattacharyya, SuvanjanIn present simulation analysis, heat transfer, pressure drop and thermal performance factor in a square channel equipped with inclined ribs with central hole is investigated. The study is conducted in turbulent flow regime with Reynolds number ranging from 10000 to 80000. The variable parameters are pitch ratio (y = p/D = 0.5, 1.0 and 1.5), hole ratio (h = d/D = 0.1 and 0.2) and rib angle (θ =30°, 45°, and 60°). ANSYS Fluent 19.0 is used for simulations and governing equation are solved using RANS turbulence model. It is revealed from the investigation that presence of inclined ribs enhance the heat transfer and pressure drop. For the case of inclined ribs with central hole, enhancement is further increased. For all the cases the thermal performance factor remains higher than unity.Item Flow and Heat Transfer Over a Moving Surface Due to Impinging Annular Jets(Springer, 2023-04) Bhattacharyya, SuvanjanIn the present paper, fluid flow and heat transfer over a moving surface owing to an array of impinging annular jets at a constant temperature have been numerically studied at a Reynolds number of 5000. The flow field was resolved using the transition SST model with highly refined mesh. In the direction of the surface movement, a periodic element from a jet-bank design was chosen. Different nondimensional surface velocities were considered from zero (stationary surface) to two times of inlet jet velocity. It is observed that both the flow field and thermal performance of the jet is strongly affected by the surface motion. The initial symmetric distribution alters when the surface motion increases up to a particular degree of surface velocity, and the average heat transfer decreases. When surface motion exceeds this threshold, net heat transmission increases which leads to the more uniform and enhance heat transfer for high surface velocity cases.Item Thermo-Hydraulic Characteristics of a Stepped Micro-Channel Under Pulsating Inlet Flow Condition(Springer, 2023-04) Bhattacharyya, SuvanjanPresent work constitutes of numerical analysis of fluid flow as well as heat transfer for a flow through a corrugated micro-channel. Water, which has a Pr = 7, is apprehended to be the fluid flowing through the corrugated channel. A sinusoidal pulsation was introduced at the inlet to regulate the inlet velocity as well as incoming volume flow rate towards the channel. A commercial code ANSYS FLUENT 19.2 was used for the inspection purpose. The flow is apprehended to be laminar and a laminar flow model was employed accordingly. The solution is carried out employing a finite volume based method. Isothermal wall boundary condition was engaged for the case, to realize the fluid flow and thermal performance of the proposed geometry. Reynolds number (Re) ranging from 1–100 was engaged for the analysis purpose. Also, a wide range of amplitude (A) of the pulsation and the frequency (f) which is represented by dimensionless Strouhal number (St), was taken on. Nusselt number, friction factor are reported characteristics to assess the overall thermal performance of the enhanced geometry.