K.N. Seetharamu

The pressure drop due to Joule-Thomson effect shows an improved effectiveness. Due to miniaturization Joule-Thomson effect are more prominent, hence it's effect should be considered. The current study on a counter-current, parallel flow cryogenic heat exchanger presents improved effectiveness due to the Joule-Thomson pressure drop. The investigatio...

The present study investigates the Joule–Thomson (JT) effect due to pressure drop on three-fluid heat exchangers (HXs) with three thermal communications. The increased miniaturization of cryogenic HXs has led to the introduction of the JT effect. The present study investigates JT effects on a three-fluid HX with three communications presenting diff...

Nano-coolants are engineered colloidal suspensions of nanoparticles in the conventional coolant (water-ethylene glycol). Use of metals and metallic oxide nanofluids at concentrations greater than 0.01 vol. % have been studied in greater detail compared to functionalized graphene nanofluids. In the present work, an experimental investigation is carr...

The combined effect of the longitudinal wall heat conduction in the partitioning wall and ambient heat‐in‐leak (HL) from the surrounding to the heat exchanger is a serious factor affecting the performance of a multifluid heat exchanger. The performance of a three‐fluid cross‐cocurrent flow heat exchanger under such circumstances is investigated in...

The optimal life of the Lithium-ion battery is ensured when cooled effectively against excessive heat generation. One such thermal management method is liquid cooling using cold plates. The purpose of this study is to find the temperature distribution and the maximum temperature across a Cold Plate Heat Exchanger in the Battery Thermal Management s...

Metals and metallic oxide nanoparticles have been studied extensively for heat transfer applications as compared to functionalized graphene and hybrid nanoparticles. Volume concentrations of nanoparticles studied have been greater than 0.01%. In the present work, an attempt is made to study the effect by adding carboxyl graphene (CG), graphene oxid...

Supercritical fluids find vast applications in numerous industries. This research work aims to develop specific heat transfer correlations for turbulent forced, forced with buoyancy effects, and free convection heat transfers from an isothermal horizontal flat plate to supercritical Nitrogen. Numerical predictions are made computationally by incorp...

Mixed convective heat transfer in a vertical parallel plate micro-porous channel with internal heat generation and viscous dissipation, varying wall heat flux ratio and wall temperature ratio at the boundaries is investigated using the Darcy-Brinkman model under local thermal non-equilibrium assumption. Numerical solution for both fluid and solid t...

In multi-fluid heat exchangers, local equalization of fluid temperatures occur(s) at certain location(s) within the heat exchanger, depending on the chosen values of the operating condition parameters and design parameters. This is referred to as a ‘temperature cross’ between the concerned fluids. The formation of the temperature cross leads to a s...

Optimization technique for a three-fluid cross-flow plate-fin heat exchanger with offset strip fins is developed, considering significant variables subjected to given constraints. The objective of optimization is focused on maximizing the hot fluid effectiveness and minimizing the number of entropy generation units in the three-fluid cross-flow pla...

Purpose Heat exchangers working in cryogenic temperature ranges are strongly affected by heat ingression from the ambient. This paper aims to investigate the effect of ambient heat-in-leak on the performance of a three-fluid cross-flow cryogenic heat exchanger. Design/methodology/approach The governing equations are derived for a three-fluid cro...

The need for compactness and efficiency of processing devices has kept increasing rapidly over the past few years. This need for compactness has driven the dice to be stacked one above the other. But with this come the difficulty of heat dissipation and its characterization because there are multiple heat sources and a single effective heat-conduct...

Nanofluid is a promising solution for the improvement of the radiator performance. In the current research work, the effect of the nanofluid carboxyl graphene on the performance of a radiator is studied. Carboxyl graphene nanoplatelets are added to 50:50 ethylene glycol–distilled water at three concentrations of 0.02, 0.03, and 0.04 vol%. The liqui...

As the technology is developing day by day, there is a requirement for enhancement in performance of automobile radiator to have a better performance of the IC Engine and fuel effectiveness. One of the major and recent approach to upgrade the performance of a radiator is that nanoparticles must be suspended in the general coolant (Ethylene Glycol –...

A feasible solution to increase the effectiveness of the radiator will be the use of stabilized nanofluid. A mixture of small amount of solid particle, whose size is less than 100nm in the fluid phase, is termed as nanofluid. In current work, a small concentration of carboxyl-graphene nanostructure sheets/flakes are used as the solid medium, where...

Thermal contact conductance (TCC) at the interface of two nominally flat surfaces is studied using inverse heat conduction analysis based on transient heat flow. Near-surface temperatures along the lateral surface of cylindrical stainless steel specimens with different surface roughness values (0.9 - 6.9 µm) were measured for a range of contact pre...

The paper presents an approach to investigate and monitor the air pollution caused by the palm oil mill. A concept of dealing with the problem from its causes is used where the sources of pollution from the stack gases were examined. The main causes were from the combustion of shell fibre and of the palm oil. However, in the boiler itself, several...

Artificial Neural Network (ANN) based on feed-forward backpropagation model is used to predict junction temperature in PBG A package. The limited results obtained from FEM (using IDEAS software) are used to train the neural network. The effect of source power, substrate and mold compound thermal conductivity, die size, substrate thickness and air v...

Steady state analysis of a single stack cold plate used for the cooling of electronic components is carried out using the finite element method. The present methodology takes into account the heat losses from the top and bottom surfaces of the stack. In addition dimensionless parameters are used in the analysis. The analysis is divided into two par...

With increasing urbanization and globalization, automotive vehicles are important than ever before to tackle the challenges of mobility. Hence it is becoming increasingly important for automotive industries and engineers to provide efficient and economical technologies. The performance of an engine is affected by various systems like the fuel suppl...

In this study, a feed-forward back-propagation Artificial Neural Network (ANN) is used to predict the stress relaxation and behavior of creep for bimaterial microcantilever beam for sensing device. Results obtained from ANSYS® 8.1 finite element (FE) simulations, which show good agreement with experimental work [1], is used to train the neural netw...

The phenomenon of forced convective heat transfer with internal heat generation in a micro-channel filled with a porous material saturated with a rarefied gas is studied using finite element method by varying wall heat flux and wall temperature ratio under local thermal non-equilibrium (LTNE) conditions. The Darcy–Brinkman model is used to describe...

A Numerical study is carried out to investigate the effect of Rayleigh number with rotation on the flow and heat transfer characteristics in a differentially heated enclosure rotating about the horizontal axis. A Fortran Code developed based on FVM is used to discretize governing equations. Upwind difference scheme for convective terms and fully im...

As the technology is emerging day by day, there is a need for some better methodology which will enhance the performance of radiator. Nanofluid is the one area which has promised the enhancement of the radiator performance. Currently, nanofluid has got a well effective solution for enhancing the performance of the automobile radiators. Suspending t...

Simulations were carried out for natural convection in a trapezoidal cavity filled with porous media to investigate the effect of uniformly and non-uniformly heated bottom wall using finite element computational procedure. The enclosure used for flow and heat transfer analysis has hot bottom wall, constant temperature cold top wall and adiabatic si...

In the current paper the effect of ambient heat in leak on transient behaviour of three-fluid heat exchangers is described using the finite element method. The solution is obtained for parallel flow three-fluid heat exchanger with two thermal communications; it is obtained for step change in the inlet temperature of hot fluid. Comparison with the p...

Optimization is carried out based on multivariable functions such as effectiveness and total cost. These two objective functions are plotted by considering various design parameters such as baffle cuts, baffle spacing’s, pitch, tube length, tube layout pattern in order to get Pareto optimal solutions and it captures the trade-off between those two...

In the present paper the transient temperature response of a counter-flow three-fluid heat exchanger with three thermal communications is investigated numerically using finite element method. Comparison with the previously published steady state results shows excellent agreement. The effects of step change in inlet temperature of fluids on time to...

Natural convection heat transfer in a two dimensional unsteady rotating differentially heated enclosure is studied numerically in this paper. The enclosure is filled with air and executes a steady counterclockwise rotation about the centre of the enclosure. A finite volume code on a staggered grid arrangement with TDMA algorithm is developed and em...

The development of heat exchangers from two streams to multi-stream passage arrangement becomes a key problem for heat exchanger design. In this paper, a new design is developed for multi-stream (four-channel) heat exchanger. Multi-channel heat exchangers are extensively used in refrigeration and air conditioning, chemical industries, milk pasteuri...

Purpose - The purpose of this paper is to analyse the dynamic behaviour of a three-fluid heat exchanger subjected to a step change in the temperature and velocity of the fluids at the inlet. Design/methodology/approach - The analysis is carried out using the finite element methodology, adopting the Galerkin's approach, using implicit method for tra...

This paper deals with an 8-bar mechanism, which finds its application in a deep drawing press. It is required in the process of deep drawing that the slider maintains an almost constant velocity during a portion of the return stroke. The approach for the kinematic simulation is based on loop closure analysis, which has been performed to derive expr...

Pressure drop predictions on the shell side of a shell and tube heat exchanger (STHX) are investigated using the concept of Finite Element Method (FEM). In this model the shell side region is discretised into a number of elements and by taking into account the effect of flow pattern, the pressure drop on the shell side of a STHX is determined. The...

This paper deals with a 6-bar mechanism, which! finds its application in a precision deep drawing press. The approach for the kinematic simulation is based on loop closure analysis, which has been performed to derive expressions for slider displacement. The results are consolidated using Artificial Neural Network (ANN). Genetic Algorithm (GA) is us...

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This paper deals with double toggle mechanism used for exerting clamping force between movable and fixed dies of a die casting machine. Loop closure method has been adopted to determine the displacement of the movable plate. In addition to stroke ratio, velocity ratio and mechanical advantage, this paper also investigates the effect of link lengths...

Natural convection is studied numerically using finite element based computational procedure. The enclosure used for flow and heat transfer analysis has been bounded by adiabatic top wall, constant temperature cold vertical walls and a horizontal bottom wall. The grid independent study has been made with different grids to yield consistent values....

In internal combustion engines, only a part of the fuel energy flow is transformed into power available at the crankshaft, while the most part of the fuel energy flow is lost as coolant, exhaust gases and other waste heat flows.The focus of this study is to evaluate the performance of three-fluid re-circulating type heat exchanger to recover energy...

A three-fluid heat exchanger for a cryogenic application, involving two thermal interactions, is investigated for the effect of ambient heat-in-leak, using both the analytical and finite element methods. Cooling of the hot fluid is identified as the objective of the threefluid heat exchanger. Six nondimensional parameters, including one to account...

This paper demonstrates the capability of curve fitting using Artificial Neural Network (ANN), not only for a moderate set of input data but also for a coarse set of input. When appropriate number of neurons is chosen for the training purpose, accurate graphs can be obtained, despite having a coarse data. The effect of number of neurons used for cu...

The engineering applications of multi fluid heat exchangers are found in petrochemical industries, aerospace, cryogenics, etc. In this paper, thermal analysis of a cross-flow three-fluid heat exchanger is carried out using the finite element method. The hot stream is assumed to exchange heat with two cross-flow cold streams. This study investigates...

In addition to operating and design parameters, the thermal performance of heat exchangers, working in cryogenic temperature range, is strongly governed by losses such as longitudinal conduction through the wall, heat-in-leak from the surroundings, flow maldistribution, etc. In this paper, a three-fluid cryogenic heat exchanger, involving two therm...

Three-fluid heat exchangers find wide usage in chemical processes and cryogenics. Knowledge of dynamic behaviour of heat exchangers is necessary for designing control and regulation systems of different industrial processes and operations, such as in nuclear reactors, cryogenic and petrochemical process plants. In the current paper, dynamic behavio...

Implementation of Finite Element Method (FEM) in transient thermal analysis usually will produce a formulation in space/time domain. This kind of space/time domain formulation leads to a set of ordinary differential equation and have to be solved in the time domain. But, the size of the equations or matrices in FEM usually are large, thus the conve...

In addition to operating and design parameters, the thermal performance of heat exchangers, working in cryogenic temperature range, is strongly governed by losses such as longitudinal conduction through the wall, heat-in-leak from the surroundings, flow maldistribution, etc. In this paper, a three-fluid cryogenic heat exchanger, involving thermal i...

Numerical predictions are made for laminar forced and mixed convection heat transfer from a plane vertical isothermal surface to near critical carbon dioxide. The variation of all the thermo-physical properties with temperature has been taken into consideration. The governing equations are integrated using the Patankar–Spalding implicit finite diff...

Simulations were carried out for natural convection in a square cavity using finite volume based computational procedure with biased quadratic elements to investigate the influence of convective boundary conditions at bottom wall. Parametric study has been carried out for a wide range of Rayleigh number (Ra) (103 ≤ Ra ≤ 108), Prandtl number (Pr) (0...

This paper deals with the numerical solution for natural convection in a vertical annular porous medium for various cold wall temperature boundary conditions and radiation parameters. The heat transfer is assumed to take place by convection and radiation. The inner wall (hot wall) of the annulus is maintained at an isothermal temperature while the...

In most cryogenic applications, heat in leak from the ambient is a significant factor for the degradation in the performance of heat exchangers. The effect of heat in leak to the cold fluid in a three-fluid heat exchanger, for a cryogenic application, involving thermal interaction between all the three fluids, has been investigated using both the a...

Study of laminar boundary layer in mixed convection from vertical plates is carried out. The surface temperature along the vertical plate is assumed to vary arbitrarily with vertical distance. Perturbation technique is used to solve the governing boundary layer equations. The differentials of the wall temperature are used as perturbation elements,...

An attempt has been made to simulate the temperature distribution in prostate cancer tissue during laser ablation using finite element approach. Parameter studies have been carried out. The results have been consolidated using tool of artificial intelligence-Artificial Neural Network. Feed forward back propagation network has been used for this pur...

Natural convection in cavities is studied numerically using a finite volume based computational procedure. The enclosure used for flow and heat transfer analysis has been bounded by adiabatic top wall, constant temperature cold vertical walls and a horizontal bottom wall. The bottom wall is subjected to uniform/sinusoidal/linearly varying temperatu...

An experimental study on pulsating heat pipe (PHP) is presented in this work. A closed loop PHP with a single U turn is fabricated and tested. The transient and steady state experiments are conducted and operating temperatures are measured. The experiments are carried out for different working fluids, heat input and for different evacuation levels....

When two thin plates or layers are bonded together, an extremely thin bond layer of third material exists between the two layers. This research work examines the effect of bond layer on the interfacial shearing and peeling stresses in a bimaterial model. Earlier papers on this topic are based on several mutually contradictory expressions for the sh...

An interfacial shearing and peeling stress model is proposed to account for different uniform temperatures and thickness wise linear temperature gradients in the layers. This upgraded model can be viewed as a more generic form to determine interfacial stresses under different temperature conditions in a bi-layered assembly. The selected shearing an...

A predictive model of thermal actuator behavior has been developed and validated that can be used as a design tool to customize the performance of an actuator to a specific application. Modeling thermal actuator behavior requires the use of two sequentially or directly coupled models, the first to predict the temperature increase of the actuator du...

The study of thermal mismatch induced stresses and their role in mechanical failure is one relevant topic to composite materials and electronic packages. An understanding of the nature of the interfacial stresses under different temperature conditions is necessary in order to minimize or eliminate the risk of mechanical failure. An accurate estimat...

This paper attempts to analyze and optimize the design of a liquid cooling module for an array of light emitting diodes (LEDs). Simulations of various models were carried out in FLUENT, CFD based software package with variations in five parameters to find the junction temperature of LEDs and pressure drop across the cooling module. The presence of...

An integral approach to the theoretical analysis for the skin friction of a non-Newtonian, power-law-fluid flow over a wedge is presented, when the inertia terms in the boundary-layer equations are small but need consideration. The method adopted for the solution of the equations considers an integrated average value of the inertia terms in the mom...

Natural convection in cavities is studied numerically using a finite volume based computational procedure. The enclosure used for flow and heat transfer analysis has been bounded by adiabatic top wall, constant temperature cold vertical walls and a horizontal bottom wall. The bottom wall is subjected to uniform / sinusoidal / linearly varying tempe...

Thermal performance of a water cooled multistack microchannel heat sink with counterflow arrangement has been analyzed using the finite element method. Performance parameters such as thermal resistance, pressure drop, and pumping power are computed for a typical counterflow heat sink with different number of stacks. The temperature distribution in...

Purpose The purpose of this paper is to present a numerical investigation on pulsating heat pipe (PHP) to study the slug velocities as a function of various parameters. Design/methodology/approach The governing equation of PHP is solved using explicit embedded Runge‐Kutta method, the Dormand–Prince pair in conjunction with MATLAB with the nomencla...

In this paper, the mass optimization of four bar linkages is carried out using genetic algorithms (GA) with single and dual constraints. The single constraint of bending stress and the dual constraints of bending and buckling stresses are imposed. From the movement response of the bar linkage mechanism, the analysis of the mechanism is developed us...

Numerical investigations with regard to the thermal characteristics of water cooled single stack and multistack microchannel heat sinks subjected to nonuniform base heating are conducted. Nonuniformities in base heating are accomplished by applying gradually increasing and gradually decreasing base heat fluxes with respect to coolant flow direction...

A 3-D study of heat transfer from three heated blocks in a square channel at a Reynolds number of 108 with height of the chip assembly as the characteristic length is presented. Heated blocks affixed to the bottom plate represent electronic chips mounted on horizontal circuit board. A hexahedron block is affixed on to the top shrouding wall over th...

Problem statement: The thermal mismatch induced interfacial stresses are one of the major reliability issues in electronic packaging and composite materials. Consequently an understanding of the nature of the interfacial stresses under different temperature conditions is essential in order to eliminate or reduce the risk of structural and functiona...

Purpose – The purpose of this paper is to apply asymptotic waveform evaluation (AWE) to the transient analysis of a two-layered counter-flow microchannel heat sink. Design/methodology/approach – A two-layered counter-flow microchannel heat sink in both steady state and transient conditions is analysed. Finite element analysis is used in the steady...

Microchannel heat sinks are widely regarded as being amongst the most effective heat removal techniques from the space constrained electronic devices. Electronic components and chips are often subjected to spatially varying heat fluxes and hot spots in certain regions. In the present work, effects of non-uniform base heating on the performance of s...

Epoxy composites containing particulate fillers-fused silica, glass powder, and mineral silica were investigated to be used as substrate materials in electronic packaging application. The content of fillers were varied between 0 and 40 vol%. The effects of the fillers on the thermal properties—thermal stability, thermal expansion and dynamic mechan...

Epoxy composites with mineral silica containing 0—60 vol% were prepared using a mechanical stirrer. Ethanol at 10wt% was used as the diluent in the epoxy system. The mechanical properties of epoxy composites were studied through flexural and single etch notch tensile mode (SEN-T) fracture toughness tests. Scanning electron microscopy (SEM) was used...

Microchannel heat sinks are widely regarded as being amongst the most effective heat removal techniques from the space constrained electronic devices. Electronic components and chips are often subjected to spatially varying heat fluxes and hot spots in certain regions. In the present work, effects of non-uniform base heating on the performance of s...

Castings are often required to have holes and recesses of various sizes and shapes. These impressions in castings can be obtained by using cores. In the present work, a numerical study of heat transfer during the solidification of steel casting with core has been presented. A conjugate conduction based finite element heat transfer analysis of metal...

Closed-form solutions for shearing and peeling stresses of trimaterial assembly were initially provided by Schmidt in 1999 [1] and Suhir in 2001 [2]. However, there exist some contradictions and inconsistencies the solutions of both Schmidt and Suhir. The contradiction arises in consideration of the exponent parameter E in the characteristic equati...

Increasing demands in the electronic packaging industries have led to the need for high-performance organic substrate material like epoxy composites. This paper investigates the effect of ethanol as diluent in epoxy composites containing 0 to 60 vol% of mineral silica. Flexural properties of epoxy composites were studied at room temperature. Therma...

In this paper, asymptotic waveform evaluation (AWE) has been successfully used for fast transient characterization of Fourier and non-Fourier heat conduction. The Fourier and non-Fourier equations are reduced to a system of linear differential equations, respectively, using finite element method and then solved with AWE. Besides providing equivalen...

In this study, a hybridized neuro-genetic optimization methodology realized by embedding finite element analysis (FEA) trained artificial neural networks (ANN) into genetic algorithms (GA), is used to optimize temperature control in a ceramic based continuous flow polymerase chain reaction (CPCR) device. The CPCR device requires three thermally iso...

A simplified general purpose analytical finite element model has been developed to analyze the thermal performance of a continuous flow polymerase chain reaction (CPCR) microdevice. The corresponding governing differential equations along with the appropriate boundary conditions have been solved using a self-developed code in Matlab®. Results obtai...

A one dimensional Finite element method (FEM) model is used to analyze two phase flow in mini/micro channels. The model is verified by comparing the results with those obtained by popular mini/micro channel correlations. Flow parameters such as the pressure drop, two phase friction multiplier void fraction and slip ratio are determined for differen...

Epoxy resin coated silica fillers composites with high percentage of filler loading, such as 80 to 95 vol.% are able to be produced by a mechanical mixing technique. The advantages of high filler loading of theses materials are noted from the thermal and flexural modulus. Apparently, the materials exhibit low coefficient of thermal expansion (CTE)...

Numerical analysis of heat transfer by convection, conduction and radiation in a saturated porous medium enclosed in a square cavity is investigated using a thermal non-equilibrium model. The flow is assumed to follow Darcy law. The governing partial differential equations are non-dimensionalised and solved numerically using finite element method....

Purpose – This paper seeks to introduce an optimization method for maximizing the effectiveness of the micro compact heat exchanger (MHE) under various geometrical parameters. Design/methodology/approach – Optimization is realized using the neuro-genetic methodology which combines the application of artificial neural network (ANN) together with ge...

The closed-form solution of thermo-mechanical analysis of tri-material assembly is initially provided by Schmidt in 1999 and Suhir in 2003. However, there exist some contradictions and inconsistencies in both the solutions of Schmidt and Suhir. The contradiction arises in consideration of the exponent parameter k in the characteristic equation. Bot...

Present study is undertaken to investigate the steady state heat transfer in a porous medium fixed in a vertical annular cylinder. A two-temperature, thermal non-equilibrium model is used to analyse the heat transfer behavior in the porous medium. The Darcy model of flow is employed. The inner surface of the vertical annulus is maintained at consta...

Heat transfer by natural convection through a vertical annular cylinder filled with porous media is investigated. The temperature at the inner surface of annular cylinder is assumed to vary according to power law, along the height of the cylinder. The outer surface is exposed to ambient temperature. The flow inside the porous medium is assumed to b...

Electronic packaging protects the integrated circuit chip from environmental and mechanical damages. Underfilling encapsulation is an electronic packaging technology used to reinforce the solder joints between chip and the substrate. For better mould design and optimization of the process, flow analysis during the encapsulation process is the first...

The present paper discusses (a) the analysis of a wire-on-tube condenser under varying operating conditions of free convection using FEM, and (b) experimental verification of the performance of two wire-on-tube condensers in a retrofitted domestic refrigerator using refrigerant R-134a. The study is motivated by the desire to investigate if the wire...

Purpose – Aims to present a finite element analysis based methodology for estimating the characteristic fatigue life of a solder joint interconnect under accelerated temperature cycling to predict the reliability performance of a flip chip package. Design/methodology/approach – The method uses the ANSYSTM finite element analysis tool along with An...

Free convection with and without radiation past a vertical plate embedded in a saturated porous medium has been analysed. The partial differential equations are non-dimensionalised and solved using Finite Element Method. Temperature distribution in the porous medium has been studied for constant and varying wall temperatures. For non-isothermal cas...

Purpose This paper's purpose is to review the design of a flip chip thermal test vehicle. Design/methodology/approach Design requirements for different applications such as thermal characterization, assembly process optimization, and product burn‐in simulation are outlined and the design processes of different thermal test chip structures includin...

Heat transfer under the influence of radiation and viscous dissipation in a square cavity filled with saturated porous medium is analysed. The flow is assumed to follow Darcy law. The governing equations are non-dimensionalised and solved numerically using finite element method. Left vertical surface of the square cavity is maintained at isothermal...

The effect of radiation and natural convection in a saturated porous medium embedded in a vertical annular cylinder has been investigated. Finite element method has been used to solve the governing equations. Influence of aspect ratio (A) and radius ratio (R) on Nusselt number is presented. The effect of radiation on heat transfer behavior is discu...

The effects of alumina (Al2O3) and zinc oxide (ZnO) fillers on the curing characteristics, thermal and mechanical properties of silicone rubber were studied. Rheometer results indicate that the incorporation of ZnO fillers retards the curing process, whereas an enhancement in cure rate was observed for Al2O3. Higher maximum torque (MH) and minimum...