Heat Transfer in Engineering

The advancements in research related to heat transfer has gathered much attention in recent decades following the quest for efficient thermal systems, interdisciplinary studies involving heat transfer, and energy research. Heat transfer, a fundamental transport phenomenon, has been considered one of the critical aspects for the development and advancement of many modern applications, including cooling, thermal systems which contain symmetry analysis, energy conservation and storage, and symmetry-preserving discretization of heat transfer in a complex turbulent flow. The objective of this book is to present recent advances, as well as up-to-date progress in all areas of heat transfer in engineering and its influence on emerging technologies

Modeling of heat transfer coefficients during condensation at low mass fluxes inside horizontal and inclined smooth tubes

In this study, in-tube condensation was conducted for mass fluxes of 100, 75 and 50 kg/m2s, and temperature differences of 1, 3, 5, 8 and 10 °C. Measurements and flow regimes were captured at various mean vapor qualities between 0.1 and 0.9 inside an inclined smooth tube with an inside diameter of 8.38 mm and 1.49 m long. Fifteen distinct inclination angles from -90° to 90° were considered while the condensation temperature was always maintained at 40 °C. The experimental results showed that the inclination angle significantly influenced the flow patterns and the heat transfer coefficients. It was also shown that the heat transfer coefficient was dependent on the temperature difference, even though this dependency was greater for downward flows than for upward flows. By using the experimental data and fuzzy C-means clustering adaptive neuro-fuzzy inference system (FCM-ANFIS) technique, a model was proposed for the prediction of heat transfer coefficients during condensation of low mass fluxes inside inclined smooth tubes. By using three statistical criteria, the performance of the proposed model was examined against experimental data and it was found that FCM-ANFIS was a strong tool for the prediction of the heat transfer coefficient based on the effective parameters of vapor quality, temperature difference and inclination angle.http://www.tandfonline.com/loi/uhte20hj2022Mechanical and Aeronautical Engineerin

Numerical modeling and optimization of waterjet based surface decontamination

The mission of this study is to investigate the high-pressure waterjet based surface decontamination. Our specific objective is to develop a practical procedure for selection of process conditions at given constraints and available knowledge. This investigation is expected to improve information processing in the course of material decontamination and assist in the implementation of the waterjet decontamination technology into practice. The development of a realistic procedure for processing of a chaotic and non-accurate information constitutes the main accomplishment of this study. The research involved acquisition of representative information about removal of brittle, elastic and viscous deposits. As a result an extended database representing jet based decoating has been compiled and feasibility of the damage free decontamination of various surfaces including highly sensitive ones is demonstrated. Artificial Intelligence techniques (Fuzzy Logic, Artificial Neural Networks, Genetic Computing) have been applied for processing of the acquired information and a realistic procedure of such an application has been developed and demonstrated. This procedure enables us to integrate available information about surface in question and existing numerical models. The developed procedure allows a user to incorporate both qualitative (linguistic) and quantitative (crisp) information into a process model and to predict operational conditions for treatment of an unknown surface using a readily detectable single experimental parameter that characterizes a deposit/substrata combination. The suggested technique is shown to perform reliably in the case of incomplete and chaotic information, where the traditional regression based methods fail. Numerical simulations of the two-phase flow inside a waterjet nozzle are conducted. Numerical solutions of the partial differential equations of the two-phase turbulent jet flow are obtained using FLUENT package. The numerical prediction of jet velocity profiles and the interface between the two phases (water - air) inside a nozzle are in good agreement with experimental data available in the literature. Thus the current problem setup and the results of simulations can be applied to improvement in the nozzle design. A realistic procedure for the design of the jet based surfaces decontamination developed, as a result of this study, is applied for optimization of the removal of the paint, rust, tar and rubber from the steel surface

Prediction of Flow in Non-prismatic Compound Open Channel using Artificial Neural Network

Every stream on the planet is one of a kind. Some are tenderly bended, others are wind, and some others are generally straight and skewed. The extent of stream geometry additionally changes from segment to area longitudinally because of various pressure driven and surface conditions called non-prismatic channel. A significant part of the examination work are observed to be done on prismatic compound channels. There has additionally been an advancement of work found for winding channels. However, a time which has been dismissed is that of the work for non-prismatic compound channels. An exertion has been made to investigate the examination business related to non-prismatic directs in various sorts of stream conditions. A trial perception has been made to examine the speed appropriation, limit shear stress dispersion and vitality loss of a compound channel with merging surge plain. The computation of Depth normal speed, vitality misfortune, limit shear stress in non-prismatic compound channel stream is more perplexing. The expectation of the stream qualities in compound channels with prismatic and non-prismatic floodplains is a testing assignment for power through pressure engineers because of the three dimensional nature of the stream Basic traditional methodologies can't foresee the aforementioned stream attributes with adequate precision, subsequently here can effortlessly implementable system the Artificial Neural Network can be utilized for forecast, approval and investigation of the stream parameters specified. The model performed entirely agreeable when contrasted and the other traditional strategies

Flow Analysis of Compound Channels With Converging Floodplains

The main objective of this research analyses is to study the flow behavior of both prismatic and non-prismatic compound channels having converging floodplains of width ratio varies from 1.8 to 1.0 and main channel aspect ratio of more than 5. Experiments were conducted for these channels in the Fluid Mechanics and Hydraulics laboratory of National Institute of Technology, Rourkela, India by making smooth, rigid, straight and converging within a concrete flume. Micro-ADV, Preston tube, notch, pointer gauge, manometers and other hydraulic equipment have been used to measure 3-d velocity, boundary shear stress, and water surface profile at different sections of the channels. The research investigates the modeling of water surface profile, distribution of longitudinal velocity, depth-averaged velocity, boundary shear stress and energy loss for overbank flow cases in both prismatic and non-prismatic sections of converging compound channels. As a complementary study to the experimental research, numerical hydrodynamic tools viz. ANSYS is applied to simulate the flow for both prismatic and non-prismatic sections of converging compound channels. All the important flow parameters are extracted numerically from the simulation results to study them vis a vis their observed values. As a prediction of flow variables in a non-prismatic converging compound channel is a much complex phenomenon, so an ANN has also been employed for prediction of depth-averaged velocity, boundary shear, and energy loss for different flow conditions. From the experimental study, new expressions for the water surface, energy loss and stage-discharge relationship for converging compound channels have been developed and validated with the present data and data sets from previous research projects. The distribution of boundary shear stress over different zones of a compound section of prismatic and non-prismatic compound channels are analyzed with several data sets of other researchers, new models for predicting subsection shear force are also suggested. Using the proposed shear models, the stage–discharge relations in case of both prismatic compound channels having different width ratio and non-prismatic compound channel of different converging angles are then evaluated. These developed models are well validated with new experimental data as well as with datasets of another researcher. The efficiency of the model has also been verified by applying natural river data sets and comparing well with other existing models

Development, Characterization of Mechanical Properties, Wear behaviour and Machining Analysis of Ceramic Composites for Bio-Medical Applications

Ceramic composites incorporating synthetic hydroxyapatite (HAp) particulate and thermoplastic polymer matrices are finding wide spread applications in bio-medical field. The fractured or damaged bone can be repaired or replaced by artificial bone materials. HAp has been tested many times as an artificial bone, especially as augmentation material in surgery work or as a coating material on bio-inert implants materials. It has shown excellent biocompatibility and bonding characteristics. Many implant materials used for last three decades are basically metals, alloys, ceramics and polymers etc. Most metals and ceramics are much stiffer than bone tissue resulting in mechanical mismatch (i.e. “stress shielding”) between the implant and the adjacent bone tissue. Metals are too stiff and pose other biocompatibility problems whereas ceramics are too brittle but polymers are too flexible and weak to meet the mechanical strength. However, polymers are popular due to their low density, good mechanical strength and easy formability. Therefore, polymeric bone implants are widely used. HAp particulates are mixed with polymer matrix through a series of processing stages involving melt compounding, granulating and micro-injection moulding. HAp is a suitable ceramic material for hard tissue replacement. In the present work, HAp is synthesized by wet chemical precipitation route. The mechanical properties such as tensile, compressive, flexural, impact and hardness are assessed for the composites varying HAp volume percentage in polycarbonate (PC) and polysulfone (PSU) polymers. The wear resistance of composites in abrasion, erosion, sliding and fretting mode is assessed in dry environment. Adaptive neuro-fuzzy inference system (ANFIS) model is proposed for prediction of wear behaviour of composites. The effect of drilling parameters on surface integrity of internal holes made on composite is assessed to provide insight into machinability (i.e. drilling) aspects of composites. The aim of this study is to develop material that has similar mechanical properties to that of human bone in order to achieve mechanical compatibility in the body, examine the various mechanical properties of ceramic composites, assess the performance of the ceramic composites under different wear modes and evaluate the performance of the composites in drilling operation. The samples were characterized by x-ray diffraction (XRD), fourier transform infrared test (FTIR), and scanning electron microscopy (SEM). Two-body abrasion wear behaviour of the composite is evaluated using pin-on-disc friction and wear test rig (ASTM G99). The experiment is conducted using three different water proof silicon carbide (SiC) abrasive papers of 400, 600 and 1000 grit size. Taguchi’s L27 orthogonal array is used to evaluate the tribological property with four control variables such as HAp volume percentage, load applied, sliding speed and track radius, each at three levels. The highest abrasive wear loss is noticed in the specimens worn with 400 grit size SiC paper. Erosion wear of ceramic composites is performed on air jet erosion test rig (ASTM G76). In this study, dry silica sand (spherical) of different particle size of 300μm, 400μm and 500μm are used as erodent. Taguchi’s L27 design is used to evaluate the tribological property with three control variables such as pressure, HAp volume, and impingement angle, each at three levels. The higher erosive wear loss is noticed in the specimens worn with 500μm erodent particle size as compared to both 300μm and 400μm erodent particle size. The sliding wear test of ceramic composites is performed on ball on plate wear tester (ASTM G194). Taguchi’s L27 design is designed to evaluate the tribological properties with three control variables such as HAp volume percentage, load applied and sliding speed, each at three levels. The fretting wear test of ceramic composites is performed on high frequency reciprocating rig (HFRR) testing machine (ASTM D6079). Taguchi’s L27 orthogonal array is used to evaluate the tribological properties with three control variables such as HAp volume, load applied and frequency, each at three levels. Since drilling is used to join the composite material with adjacent bone tissue in orthopaedic surgery, it is important to study drilling performance of the composite. Experiments have been conducted on a CNC milling machine using Taguchi’s L27 design with four control variables such as HAp volume percentage, drilling speed, feed rate and drill bit diameter, each at three levels. The responses considered are circularity at entry and exit, torque and thrust force. The circularity at both entry and exit is measured using the ratio of minimum diameter (Dmin) to maximum diameter (Dmax) of the drilled hole. The torque and thrust force are measured using drill dynamometer. Best parametric setting for simultaneous optimization of multiple performance measures such as circularity at entry, circularity at exit, torque and thrust in drilling operation is suggested using principal component analysis

Experimental study for determination of infiltration rate of soils in field using double ring infiltrometer

Infiltration is the process of penetration of water into the ground surface and the intensity of this process is known as infiltration rate. The infiltration rate is expressed in term of volume of water poured per ground surface per unit of time. Soil erosion, surface runoff & ground water recharge are affected by this process. At a certain moment the maximum infiltration rate can be indicated by the infiltration capacity of soil. Infiltration of water into the soil can be determined by a simple instrument called Double ring infiltrometer. The cylindrical ring infiltrometer consist of single metal cylinder. These cylinders are partially inserted into the ground and water is filled up to a margin inside the cylinder and after that the speed of penetration of water is measured with respect to the time and depth of penetration of water inside the cylinder. Four types of cylinders are taken for this experiment of diameter 15cm, 30cm, 45cm & 60cm and they are experimented as 15-45cm & 30-60cm double ring infiltrometer. To spread the water vertically after infiltration we use double ring infiltrometer. Double ring infiltrometer is better than single ring infiltrometer. In single ring infiltrometer the water will spread horizontally & vertically both, from which water will not move only towards the ground water but using double ring infiltrometer the water will penetrate in one direction that is towards the ground water without much wastage of water

CFD and neuro-fuzzy modelling of fuel cells

This thesis presents some model developments for the simulation and optimization of the design of fuel cells, in particular for the Solid Oxide Fuel Cell (SOFC) and Proton Exchange Membrane Fuel Cell (PEMFC). However, the approaches and models presented can be basically applied to any type of fuel cell. In this study, the multicomponent diffusion processes in the porous medium of a SOFC anode has been investigated through comparison of the Stefan Maxwell Model, Dusty Gas Model and Binary Friction Model in terms of their prediction performance of the concentration polarization of a SOFC anode to mainly investigate the effect of the Knudsen diffusion on the predictions. The model equations are first solved in 1 D using an in-house code developed in MATLAB. Then the diffusion models have been implemented into COMSOL to obtain 2D and 3D solutions. The model predictions have been evaluated for different parameters and operating condi- tions for an isothermal system and assuming that reaction kinetics are not rate limiting. The results show that the predictions of the models are similar and the differences in the predictions of the models reported previously are mainly due to the definition of the effective diffusion coefficient, i.e. the tortuosity parame- ter, and with a tortuosity parameter fitted for each model, the models that take into account the Knudsen diffusion and that do not predict similar concentration polarization. Moreover, in this research, the application of an Adaptive Neuro- Fuzzy Inference System (ANFIS) to predict the performance of an Intermediate Temperature Solid Oxide Fuel Cell and a Proton Exchange Membrane Fuel Cell (PEMFC) have been presented. The results show that a well trained and tested ANFIS model can be used as a viable tool to predict the performance of the fuel cell under different operational conditions to facilitate the understanding of the combined effect of various operational conditions on the performance of the fuel cell and this can assist in reducing the experimentation and associated costs

Prediction of flow in non prismatic compound open channel using artificial neural network

Each river in the world is unique. Some are gently curved, others are meander, and some others are relatively straight and skewed. The size of river geometry also changes from section to section longitudinally due to different hydraulic and surface conditions called non-prismatic channel. Much of the research work are found to be done on prismatic compound channels. There has also been a progress of work found for meandering channels. But an era which has been neglected is that of the work for non-prismatic compound channels. An effort has been made to scrutinize the research work related to non-prismatic channels in different types of flow conditions. An experimental observation has been made to investigate the velocity distribution, boundary shear stress distribution and energy loss of a compound channel with converging flood plain. The calculation of Depth average velocity, energy loss, boundary shear stress in non-prismatic compound channel flow is more complex. The prediction of the flow characteristics in compound channels with prismatic and non-prismatic floodplains is a challenging task for hydraulics engineers due to the three dimensional nature of the flow. Simple conventional approaches cannot predict the above mentioned flow characteristics with sufficient accuracy, hence in this area an easily implementable technique the Artificial Neural Network can be used for prediction, validation and analysis of the flow parameters mentioned. The model performed quite satisfactory when compared with the other conventional methods