bluuebunny/crossref_metadata_2025 huggingface dataset:
Found Guilty by Association: In Defence of the Quinean Criterion
Authors: Egerton Karl
Published: August 2016

Much recent work in metaontology challenges the so‐called ‘Quinean tradition’ in metaphysics. Especially prominently, Amie Thomasson argues for a highly permissive ontology over ontologies which eliminate many entities. I am concerned with disputing not her ontological claim, but the methodology behind her rejection of eliminativism – I focus on ordinary objects. Thomasson thinks that by endorsing the Quinean criterion of ontological commitment eliminativism goes wrong; a theory eschewing quantification over a kind may nonetheless be committed to its existence. I argue that, contrary to Thomasson's claims, we should retain the Quinean criterion. Her arguments show that many eliminativist positions are flawed, but their flaws lie elsewhere: the Quinean criterion is innocent. Showing why reveals the importance of pragmatism in ontology.

In §1 I compare Thomasson's account and the eliminativist views to which it stands in opposition. In §2 I re‐construct Thomasson's reasons for rejecting the Quinean criterion. In §3 I defend the Quinean criterion, showing that the eliminativists’ flaws are not consequences of applying the Quinean criterion, before explaining the criterion's importance when properly understood. I conclude that Thomasson, though right to criticise the methodology of ordinary‐object eliminativists, is wrong to identify the Quinean criterion as the source of their mistake.
Religion and Latin drama in the early modern Low Countries
Authors: Bloemendal Jan
Published: August 2016

In the sixteenth and seventeenth centuries the Low Countries were a melting pot of religious beliefs: Roman Catholicism and several Protestant and Catholic Reformation movements coexisted together, the ‘radical Reformation movement’ of the Anabaptists, the ‘militant movement’ of Calvinism, and the more mild variant of Lutheranism. The Southern part of the Low Countries were ‘re‐catholicized’ after the Fall of Antwerp in 1585, and the Counter‐ Reformation was active there. Authors of several denominations wrote Latin plays. In this article I will look at the theology represented in some of these plays, particularly those of Macropedius and Laurimanus as examples of Roman Catholic (non‐Jesuit) plays; those of Lummenaeus a Marca and Libenius as examples of Jesuit drama; and those of Gnapheus as examples of Protestant theatrical writing. Thus, it will be possible to draw some general conclusions about religion, theology and confessionalization in neo‐Latin drama of the Low Countries.
Byzantine tragedy in Restoration England: Joseph Simons's Zeno and Sir William Killigrew's The Imperial Tragedy
Authors: Shell Alison
Published: August 2016

The history of the Byzantine era is rich in dramatic potential, and was extensively exploited by writers of continental Catholic school and college drama in the early modern period. However, it was hardly ever drawn upon within Tudor and Stuart professional drama. One exception to this rule is Zeno, written by Joseph Simons SJ, freely adapted by Sir William Killigrew and printed in 1669 under the title The Imperial Tragedy. Killigrew's play is also unusual because plays written and performed in the English Catholic colleges on the continent during the sixteenth and seventeenth centuries were very seldom acknowledged, printed or adapted on the English mainland.

The adaptation suggests a personal relationship between the two playwrights. Simons was attached to the London court at this period as Jesuit Provincial; Killigrew, a courtier, appears to have been on friendly terms with Simons in the late 1660s, and to have wanted to pay him a compliment by adapting his play. However, he printed it anonymously, not mentioning either Simons's name or his own. It is likely that he did this because Simons was a controversial associate: not least for his influence over the future James II, whom he converted to Roman Catholicism. Killigrew appended a tantalising title page to his work, suggesting that there was more to his anonymity than mere modesty, and came clean about his authorship to the semi‐private audience with which he also shared his revisions: an audience which included at least one individual with a pronounced interest in religious toleration.

At this time, the gift of books could cement literary and personal alliances, and manuscript circulation could define friendship and patronage networks. The two surviving copies of The Imperial Tragedy annotated by Killigrew give us something in between: a case study of how an author's previously printed material could be personalized by religiously sensitive manuscript additions for an inner circle.
Prediction of Non-Equilibrium Heat Conduction Using Parallel Computation of the Phonon Boltzmann Transport Equation
Authors: Ali Syed A. , Kollu Gautham , Mazumder Sandip , Sadayappan P.
Published: August 2016

Non-equilibrium heat conduction, as occurring in modern-day sub-micron semiconductor devices, can be predicted effectively using the Boltzmann Transport Equation (BTE) for phonons. In this article, strategies and algorithms for large-scale parallel computation of the phonon BTE are presented. An unstructured finite volume method for spatial discretization is coupled with the control angle discrete ordinates method for angular discretization. The single-time relaxation approximation is used to treat phonon-phonon scattering. Both dispersion and polarization of the phonons are accounted for. Three different parallelization strategies are explored: (a) band-based, (b) direction-based, and (c) hybrid band/cell-based. Subsequent to validation studies in which silicon thin-film thermal conductivity was successfully predicted, transient simulations of non-equilibrium thermal transport were conducted in a three-dimensional device-like silicon structure, discretized using 604,054 tetrahedral cells. The angular space was discretized using 400 angles, and the spectral space was discretized into 40 spectral intervals (bands). This resulted in ∼9.7×109 unknowns, which are approximately 3 orders of magnitude larger than previously reported computations in this area. Studies showed that direction-based and hybrid band/cell-based parallelization strategies resulted in similar total computational time. However, the parallel efficiency of the hybrid band/cell-based strategy — about 88% — was found to be superior to that of the direction-based strategy, and is recommended as the preferred strategy for even larger scale computations.
Review and Comparison of Ejectors Design Methods and Their Application
Authors: Tan Taide , Liu Jiyun , Chen Han , Lu Wei
Published: August 2016

Ejectors are efficient equipment for low-grade heat recovery and new energy exploitation and utilization. However, the current design of the ejectors is still relying on traditional methods emerged several decades ago. Several classic ejectors design theories and methods have been reviewed and discussed in this paper. Parametric study have been conducted by self developed programs. The calculations have been benchmarked with theoretical data and previous data from other researchers. This paper is also trying to provide a guide for the ejector design in order to achieve the best efficiency.
A Systematic Study of Pool Boiling Heat Transfer on Multiscale Structured Surfaces
Authors: Rioux Russell P. , Nolan Eric C. , Li Calvin H.
Published: August 2016

A study has been conducted to examine the effects of macroscale, microscale, and nanoscale surface modifications in water pool boiling heat transfer and to determine the effects of combining the multiple scales. Nanostructured surfaces were created by acid etching, while microscale and macroscale surfaces were manufactured through a sintering process. Six structures were studied as individual and/or collectively integrated surfaces: polished plain, flat nanostructured, flat porous, modulated porous, nanostructured flat porous, and nanostructured modulated porous. Boiling performance was measured in terms of critical heat flux (CHF) and heat transfer coefficient (HTC). Both HTC and CHF have been greatly improved on all modified surfaces compared to the polished baseline. The CHF and HTC of the hybrid multiscale modulated porous surface have achieved the most significant improvements of 350% and 200% over the polished plain surface, respectively. Nanoscale, microscale, and macroscale integrated surfaces have been proven to have the most significant improvements on HTC and CHF. Experimental results were compared to the predictions of a variety of theoretical models with an attempt to evaluate both microscale and nanoscale models. It was concluded that models for both microscale and nanoscale structured surfaces needed to be further developed to be able to have good quantitative predictions of CHFs on structured surfaces.
Liquid Characteristics Under Melting/Solidification Conditions Using Energy Conserving Dissipative Particle Dynamics
Authors: Johansson Erik , Yamada Toru , Yuan Jinliang , Sundén Bengt , Asako Yutaka , Faghri Mohammad
Published: August 2016

In this paper, energy conserving Dissipative Particle Dynamics (DPDe) is used to study liquid characteristics when the walls are kept at a melting temperature. The formulation of the phase change problem is based on the latent heat model available in the literature. It is incorporated into the DPDe method to simulate a one-dimensional solid-liquid moving boundary problem. The solution domain is considered to be a two-dimensional Cartesian box where DPDe particles are randomly distributed. Periodic boundary conditions are applied in the flow direction and solid DPDe particles are placed as additional layers on the top and bottom of the domain. The DPDe result was compared with the available analytical solution and the effects of the DPDe parameters and thermal characteristics are discussed.
Comparison of Phase Function Normalization Techniques for Radiative Transfer Analysis Using DOM
Authors: Hunter Brian , Guo Zhixiong , Frenkel Matthew
Published: August 2016

Five phase-function (PF) normalization techniques are compared using the discrete-ordinate method (DOM) for modeling diffuse radiation heat transfer in participating media. Both the mathematical formulation and the impact on the conservation of both scattered energy and PF asymmetry factor for both Henyey-Greenstein (HG) and Legendre PF distributions are presented for each technique. DOM radiation transfer predictions generated using the five normalization techniques are compared to high-order finite-volume method, to gauge their accuracy. The commonly implemented scattered energy averaging technique cannot correct asymmetry factor distortion after angular discretization, and thus large errors due to angular false scattering are prevalent. Another three simple techniques via correction of one or two terms in the PF are shown to reduce normalization complexity whilst retaining diffuse radiation computation accuracy for HG PFs. However, for Legendre PFs, such simple normalization is found to result in unphysical negative PF values at one or few correction directions. The relatively complex Hunter and Guo 2012 technique, in which normalization is realized through a correction matrix covering all discrete directions, is shown to be highly applicable for both PF types.
A Robust and Efficient Thermographic NDE Tool Based on an Inverse VoF Meshless Method
Authors: Saad Hussein , Divo Eduardo , Boetcher Sandra , Brown Jeff , Kassab Alain
Published: August 2016

A novel computational tool based on the Localized Radial-basis Function (RBF) Collocation (LRC) Meshless method coupled with a Volume-of-Fluid (VoF) scheme capable of accurately and efficiently solving transient multi-dimensional heat conduction problems in composite and heterogeneous media is formulated and implemented. While the LRC Meshless method lends its inherent advantages of spectral convergence and ease of automation, the VoF scheme allows to effectively and efficiently simulate the location, size, and shape of cavities, voids, inclusions, defects, or de-attachments in the conducting media without the need to regenerate point distributions, boundaries, or interpolation matrices. To this end, the Inverse Geometric problem of Cavity Detection can be formulated as an optimization problem that minimizes an objective function that computes the deviation of measured temperatures at accessible locations to those generated by the LRC-VoF Meshless method. The LRC-VoF Meshless algorithms will be driven by an optimization code based on the Simplex Linear Programming algorithm which can efficiently search for the optimal set of design parameters (location, size, shape, etc.) within a predefined design space. Initial guesses to the search algorithm will be provided by the classical 1D semi-infinite composite analytical solution which can predict the approximate location but not the size or shape of the cavity. The LRC-VoF formulation is tested and validated through a series of controlled numerical experiments. The proposed approach will allow solving the onerous computational inverse geometric problem in a very efficient and robust manner while affording its implementation in modest computational platforms, thereby realizing the disruptive potential of the proposed multi-dimensional high-fidelity non-destructive evaluation (NDE) method in displacing the current practice of 1D-based NDE.
Characterization of Fouled Flat Sheet Membranes by Infrared Thermography
Authors: Ndukaife Kennethrex O. , Nnanna George Agbai
Published: August 2016

An Infrared thermography (IRT) technique for characterization of fouling on membrane surface has been developed. The emitted spectral power from the fouled membrane is a function of emissivity and surface morphology. In this work, a FLIR A320 IR camera was used to measure surface temperature and emissivity. The surface temperature and the corresponding emissivity value of various areas on the fouled membrane surface is measured by the infrared camera and recorded alongside its thermogram. Different fouling experiments were performed using different concentrations of aluminum oxide nanoparticle mixed with deionized water as feed solution (333 ppm, 1833 ppm and 3333 ppm) so as to investigate the effect of feed concentration on the degree of fouling and thus its effect on the emissivity values measured on the membrane surfaces. Surface plots in 3D and Line plots are obtained for the measured emissivity values and thickness of the fouling deposit on the membrane surface respectively. The results indicate that the IRT technique is sensitive to changes that occur on the membrane surface due to deposition of contaminants on the membrane surface and that emissivity is a function of temperature, surface roughness and thickness of the specimen under investigation.
Microporous Coating by Dual-Stage Electroplating to Enhance Pool Boiling Performance of Saturated R-123 and FC-72
Authors: Kwark Sang M. , Kim Joo Han , You Seung M.
Published: August 2016

The present study describes a dual-stage electroplating method developed to construct numerous active nucleation sites on a target surface for the purpose of enhancing the pool boiling heat transfer performance. Electroplating with high current densities (0.17 ∼ 1.2 A/cm2) builds micro-scale copper dendrites and nodules on the base surface (oxygen free copper) and low current density electroplating (fixed, 0.05 A/cm2) follows to achieve the strong bonding strength of the micro-structures, which enable the coating to be robust in terms of corrosion and endurance. Pool boiling experiments show that the electroplated surfaces extend the boiling critical heat flux by 40∼70% for two working fluids tested and augment the boiling heat transfer coefficients by ∼700% and ∼600% in saturated R-123 and FC-72, respectively, at atmospheric pressure over a baseline (plain surface).
Novel Heat Exchanger Design With Rectangular Shell Geometry
Authors: Patel Vipul , Patel Rajesh , Savsani Vimal
Published: August 2016

Shell and Tube Heat Exchangers (STHE) are the most versatile type of heat exchangers used in industrial applications. The shape of Shell side of the traditional STHE’s is cylindrical for industrial applications. On one hand, STHE have some good features but on the other hand, it has some limitations due to the cylindrical geometry of the shell side. Some of these limitations are maximum two shell pass is possible as per TEMA layout, complete counter flow cannot be achieved, possibility of reverse heat transfer when number of tube passes are more, tubes are always laid parallel to shell and mounting over the entire length of shell is not possible when impingement plate provided etc. The objective of this study is to design a novel heat exchanger to overcome the limitations of traditional STHE. An experimental setup has been designed with rectangular shell side for STHE. The novel heat exchanger provides the flexibility to increase the number of shell pass and complete counter flow can be achieved due to rectangular geometry of shell side. For the same heat transfer rates, the proposed novel heat exchanger design provides better Effective Mean Temperature Difference (EMTD) and hence less surface area for heat transfer in comparison with traditional STHE. The experiments have been conducted on novel heat exchangers under different operation conditions of hot and cold fluids. The experiment results are compared with theoretical estimations of overall heat transfer coefficient and Log Mean Temperature Difference (LMTD) for traditional shell and tube heat exchangers for the same operation conditions. The results show that under the same operation conditions, the performance of novel heat exchanger is much better than traditional STHE.
Enhancement of Heat Transfer Coefficient in an Automobile Radiator Using Multi Walled Carbon Nano Tubes (MWCNTS)
Authors: Ramaraju Ramgopal Varma , Kota Manikantan , Manap Hadi Bin , Veeredhi Vasudeva Rao
Published: August 2016

Enhancement of heat transfer coefficient continues to be an important research area in various fields of engineering ranging from microelectronics to high powered automobiles. The initial effort in the present research study is to enhance the heat transfer coefficient in a vehicle radiator using nanofluids with high thermal conductivity. The world’s most abundant element ‘Carbon’ astoundingly exists in various structures and one such form is tube commonly known as Carbon Nanotubes (CNTs). Heat transfer enhancement in water and coolant based systems with different concentrations of nano particles (carbon nanotubes) have been investigated from an engineering system perspective. One such system considered is a “SUZUKI (800CC) - CAR RADIATOR”, cooling circuit using different nanofluids to replace the conventional engine coolant. In the present study, the effect of nano-fluid heat transfer to enhance in water and coolant based systems with multi walled carbon nanotubes has been investigated. The improvement of heat transfer when compared to water, coolant (water + ethylene glycol 60:40) and water with MWCNTS and coolant with MWCNTS has been studied.

It has been observed that there is an enhancement of heat transfer up to 30% when coolant and CNTS are used as a cooling medium.
Transient Performance of Multi-Pass Parallel and Counterflow Crossflow Heat Exchangers
Authors: Silaipillayarputhur Karthik , Idem Stephen A.
Published: August 2016

The step response of a multi-pass crossflow heat exchanger was determined for variable inlet temperatures and mass flowrates. In every instance overall parallel and counterflow circuiting was considered. The energy balance equations were solved using an implicit central finite difference method. Numerical predictions were obtained for the case where the minimum capacity rate fluid was subjected to a step change in inlet temperature while mass flowrates for both fluids were maintained constant. Under those circumstances it was demonstrated that for short times the transient response of a counterflow heat exchanger was nearly independent of the number of passes. Likewise the transient performance was calculated when a step mass flowrate change of the minimum capacity rate fluid was imposed, in the absence of any temperature perturbations. In that situation the transient heat exchanger response was influenced by the number of passes for both parallel and counterflow circuiting.
Analytical and Experimental Study to Predict Radiated Heat Power Between a Satellite and Thermal Shroud
Authors: Schwendtner Daniel T. , Amin M. Ruhul , Klumpar David M.
Published: August 2016

Nanosatellites, a class of small satellites, are becoming increasingly popular because of their small form factor and many other attractive features. In the process of qualifying nanosatellites for space readiness, their thermal behavior can be investigated in a laboratory setup using a thermal vacuum system to mimic orbital conditions. For these reasons, a thermal vacuum system suited specifically for nanosatellites was desired for performing thermal vacuum testing. Analytical calculations and laboratory testing were performed as part of the design of this thermal vacuum system. A set of simultaneous equations was solved using the LU Decomposition method to find the radiosities of several surfaces in an enclosure. The radiosities along with their respective view factors were then used to solve for the heat power required to heat and cool the thermal shroud under steady state conditions at the most extreme operating conditions expected. The analysis was performed on a system of three concentric cylinders of varying heights: the outer being the vacuum chamber wall, the middle the thermal shroud inside the chamber, and the inner the satellite.

Under the most extreme operating conditions expected, the thermal shroud was cooled to −40°C and the satellite heated to 80°C during satellite cooling and the reverse during satellite heating. All surfaces in the enclosure were assumed to be diffuse, grey, opaque and isothermal. The thermal shroud was separated into two surfaces: the cylindrical shroud body and the shroud top disc. From the analytical results, the expected heating power for the shroud body was found to be 704.0 Watts, and 229.8 Watts for the shroud top. During cooling, where the temperatures were reversed, the expected heat power for the shroud body was calculated as −685.5 Watts, and −220.9 Watts for the shroud top.

An experimental setup was tested under similar conditions as a comparison and as a method to validate the thermal shroud design and the analytical calculations. The shroud body and top heaters were selected to output 750 Watts and 230 Watts, respectively, and were driven at their maximum output, with the satellite held at −40°C. The shroud reached 80°C with no difficulty, indicating that the analytical calculations had correctly predicted the required heat power and that the design of the thermal shroud was capable of supporting testing under the most extreme conditions expected.
Investigation of Building Passive Thermal Storage for Optimal Heating System Design
Authors: Ogunsola Oluwaseyi , Song Li
Published: August 2016

Heating and cooling load calculations are critical to size Heating, Ventilation and Air conditioning (HVAC) systems and determine energy use of their operations. The ASHRAE (2009) model, which is most commonly used for heating load calculations, adopts a simplified approach by considering only steady-state instantaneous conductive heat transfer and ignoring internal heat gains and thermal storage effects. Those assumptions evaluate the worst case conditions which can reasonably occur at nights when the outdoor air temperature is lowest and with no inputs from solar, occupants, lights, or any electronic devices. However, due to thermal storage effect, heat generated in daytime can be still stored in buildings. Such ignorance leads to significantly over-sized heating system, high initial cost and a higher cost of energy uses. On the other hand, by considering passive thermal storage of buildings and allowing space air to drift to reasonably lower values, buildings need to be warmed up in the morning before being occupied. The worst case conditions might happen in the morning warm-up period, when heating is needed. This study therefore examines the thermal response of different constructions (heavy, medium, and light) of the building envelope and investigates the effect of their passive thermal storage on the size of the heating system. Results show tremendous opportunities for downsizing of the heating system while still maintaining thermal comfort requirements. As such, this paper is a fundamental study of building thermal characteristics in order to investigate the potentials of establishing a new heating device design standard.
A Computational Study of HCCI Engine With External Mixture Formation Technique
Authors: Sharma T. Karthikeya , Rao G. Amba Prasad , Kotha Madhu Murthy
Published: August 2016

HCCI combustion is gaining increased attention amongst the research community to make it viable in both diesel and gasoline engines. Of late, technique of External mixture formation is being adopted to avoid the problems associated with the early injection and late injections of the direct injected diesel HCCI engine. This paper reports the numerical studies on the effect of External mixture formation using three-zone extended coherent flame (ECFM-3Z) CFD model of the STAR - CD package. Firstly, the results obtained through package were validated with the results available in the literature. Trade-off between HC, CO and NOx was clearly observed through simulation. The simulation results revealed decrease in in-cylinder pressures and NOx emissions with increase in EGR concentration. There is an under prediction of NOx emissions when compared with the experimental results. However, a significant reduction in NOx emissions was observed with external mixture formation, usage compared to direct diesel injection. In case of HC and CO emissions increasing trend was observed with increase in EGR concentration. Increase in HC and CO emissions was observed with external mixture formation when compared with a direct diesel injection. Also, reduction in turbulent kinetic energy and velocity magnitude levels were observed with increase in EGR concentration. Improved piston work is resulted at lower EGR concentrations. Studies revealed that for a given combustion bowl geometry, It is concluded that external mixture formation technique could be adopted to achieve HCCI combustion.
Comparison of Heat and Mass Transfer Characteristics of Absorption of R134a in DMAC and DMF for a Falling Film Horizontal Tube Absorber
Authors: Yadu Kamal Kant , Tiwari Shaligram , Manoor Prakash Maiya
Published: August 2016

The present work is a comparative study of heat and mass transfer behaviour during the absorption of R134a (1, 1, 1, 2 Tetrafluroethane) vapour into absorbents, DMAC (N, N-Dimethylacetamide) and DMF (N, N-Dimethylformamide). Initially, the heat and mass transfer characteristics for absorption of R134a into DMF for a falling film horizontal tubular absorber have been investigated by employing a two-dimensional numerical technique. The related governing equations are solved using a developed computer code in MATLAB. Then, a comparison of absorption characteristics of R134a-DMAC and R134a-DMF is made. For the mean value of operating parameters considered, the R134a-DMF solution absorbs more due to higher diffusion coefficient value of DMF than DMAC. The mass transfer coefficient is observed to decrease at a steeper rate at the entrance of the first tube for both working fluids, after which gradual decrease in the mass transfer coefficient is observed further downstream.
Numerical Study of Characteristics of Burning Phenomena in Equidistant Square Arrayed n-Heptane Fires
Authors: Satoh Koyu , Liu Naian , Xie Xiaodong , Gao Wei
Published: August 2016

Merging of large-scale city fires and forest fires causes rapid acceleration of fire growth. Once a merging fire occurs, it becomes more difficult to suppress, with greater potential damages. In particular, merging fires may induce fire whirls in windy conditions. However, the details of interactions in multiple fires that cause fire merging have not been fully clarified. For the interactions in multiple fires, the inter-fire distance among fires greatly affects the merging phenomenon. The objective of this paper is to examine the detailed merging conditions, particularly the burning rate increase and total heat release rate, by numerical simulation of reduced scale fires. The burning behavior of n-heptane in n × n fire arrays is examined, using the fire simulation software, FDS by NIST. In addition, another simple model is employed. The number of array matrix, n, is varied, together with the inter-fire distance. The simulation results show that there are considerable differences between both simulations and experiments. However, the differences between the simpler simulation Method II and experiments are fewer than the simulation Method I. The following possibilities are considered: (1) The oil pan size affects the difference, but the results between simulations and experiments are so large. (2) The grid size for simulations may have some effects on the simulation results due to the resolution, (3) the experimental results may not always be precise, since the burning rates in the experiments are measured by the burn-out time and (4) the wind caused by merging fires may reduce the radiative heat flux to the adjacent fuel. The relationship between flame length and burning rate and the relationship between flame length and radiative heat flux are well-correlated.
Direct-Coupling Simulation of Thermal-Hydraulic and Stress Analysis in a Cross-Wave Primary Surface Heat Exchanger
Authors: Zhang J. , Ma T. , Zeng M. , Ekkad S. V. , Wang Q. W.
Published: August 2016

Fluid flow with heat transfer in the Cross Wave (CW) primary surface channels may cause an external stress in the plate due to the non-uniform pressure on the plate surface and non-uniform temperature inside the plate. The plate construction can be deformed under this external stress, which will affect the flow of the fluid by changing the channel dimensions and thus affect the temperature fields. To solve the multi-physical field problem, a direct-coupling simulation method of thermal-hydraulic and stress analysis in a Crow-Wave (CW) primary surface heat exchanger is presented in this paper. The method is based on the commercial code STAR-CD and ABAQUS, and an in house procedure is added to accomplish the direct-coupling simulation in a transient process between thermal-hydraulic and stress modules. Due to the complicated simulation of fluid flow and heat transfer in a two-coupled CW fluid channels in which each channel is separated by the plate (original model) in the CFD (Computer Fluid Dynamics) procedure, an alternative CFD model that is different from the original model is constructed to enable the CFD analysis. The detailed geometry of the original mode is generated in the CAE (Computer Aided Engineering) procedure. A data transition program is developed to control and transform analysis data between the CFD model and the CAE model. The coupling relationship of surface pressure, temperature and the material stress in the CW primary surface heat exchanger is uncovered. The results indicates that the high thermal stress and large displacement about 2.26 × 103 MPa of stress and 8.28 × 10−2 mm of displacement are generated at the beginning of time steps. Therefore, more attention should be paid during the starting up and emergency stop process due to the excessive build of stress during the transient conditions.
Numerical Investigation of Laminar Filmwise Condensation of Water Vapor in Horizontal Tube With VOF Method in the Presence of Air
Authors: Yin Zhan , Wen Jianjun , Zeng Min , Wang Qiuwang
Published: August 2016

A steady three-dimensional numerical simulation of laminar film condensation of vapor in the presence of air inside a 1 mm horizontal tube is presented. The volume of fluid (VOF) method is used to capture the liquid-vapor interface with a phase change model. According to a generally accepted flow regime map, annular flow pattern is to be expected. Uniform wall temperature and interface temperature are assumed to be boundary condition. The influence of gravity is obvious while the effect of surface tension is neglected. At inlet, the liquid film is thin and evenly distributed around tube wall. Moving downstream the tube, film at the bottom half becomes thicker under the influence of gravity, while film on upper half remains almost constant. Correspondingly, local heat transfer coefficient on bottom half declines gradually and global average heat transfer coefficient shows little difference along axial direction. Existence of air makes heat transfer coefficient decrease sharply compared with that of pure vapor condensation, caused by an existed air layer which increases the thermal resistance during condensation process. As inlet volume fraction of air increases from 0.5% to 3%, the decline trend of heat transfer coefficient slows down.
Thermal Spreading Resistance in Flux Channel With Arbitrary Heat Convection in the Sink Plane
Authors: Razavi Masood , Muzychka Yuri S. , Kocabiyik Serpil
Published: August 2016

Thermal spreading resistance is one of the key factors for designing the thermal management systems in microelectronic devices. This type of thermal resistance occurs in most of the microelectronic devices and causes some difficulties for thermal engineers to model the system. One of the common geometries in these devices is the flux channel. Different boundary conditions can be applied on the flux channel based on the designing criteria of the system including the arbitrary distribution of heat sinks over the sink plane. This boundary condition is usually simplified as a constant heat transfer coefficient to facilitate the modeling of the system. In this paper, a flux channel with an arbitrary distributed heat transfer coefficient over the sink plane is studied without simplification of the sink boundary condition. Both adiabatic and convective cooling over the edges of the flux channel are considered. Due to the complexity of the sink boundary condition, the conventional analytical solutions are not applicable and the method of least squares is used. By employing this approach, the effect of a non-uniform heat transfer coefficient on thermal spreading resistance is investigated. The solution is presented in form of a Fourier series expansion which can be used to obtain the temperature all over the channel. Results are validated with Finite Element Models, FEM. This approach is useful for thermal engineers who have some difficulty for modeling complex boundary conditions and presents an effective solution for thermal resistance in the flux channels.
Study on Nucleate Boiling Heat Transfer by Measuring Detailed Surface Temperature Distribution and Variation With Infrared Radiation Camera
Authors: Takahashi Kazuki , Koizumi Yasuo
Published: August 2016

Pool boiling heat transfer experiments were performed for water at 101 kPa to examine elementary process of nucleate pool boiling. The heat transfer surface was made from a copper printed circuit board. The size of the heat transfer surface was 10 mm × 10 mm. Direct current was supplied to the heat transfer surface to heat it up. The Bakelite plate of the backside of the copper layer was taken off at the center portion of the heat transfer surface. The test vessel was a closed 200-mm cube container made of duralumin. It has transparent view windows on opposing side walls made of a Polycarbonate plate to observe a boiling state. Heat transfer surface was placed at the bottom of the test vessel. Distilled water was used for the experiments. The instantaneous variation of the backside temperature of the heat transfer surface was measured with an infrared radiation camera. Bubble behavior was recorded with a high speed video camera. The time and the space resolution of the infrared radiation cameras used in present experiments were 60 Hz and 0.1 mm × 0.1 mm, and 120 Hz and 0.315 mm × 0.315 mm, respectively. When the heat flux was increased, the instantaneous surface temperature variation explain the pattern. In the isolated bubble region, surface temperature was uniform during waiting time. When boiling bubble generation started, a large dip in the surface temperature was formed under the bubble. After the bubble left from the heat transfer surface, the surface temperature returned to former uniform temperature distribution. Surface temperature was not affected by the bubble generation beyond 1.8 mm from the center of the bubble. In the intermediate and high heat flux region, the variation of surface temperature and heat flux were small. Rather the heat flux variation range was close to that at the isolated boiling region.
Nucleate Boiling of Dielectric Liquids on Hydrophobic Patterned Surfaces
Authors: Joshua Nihal E. , Ajakumar Denesh K. , Bostanci Huseyin
Published: August 2016

This study experimentally investigated the effect of hydrophobic patterned surfaces in nucleate boiling heat transfer. A dielectric liquid, HFE-7100, was used as the working fluid in the saturated boiling tests. Dielectric liquids are known to have highly-wetting characteristics. They tend to fill surface cavities that would normally trap vapor/gas, and serve as active nucleation sites during boiling. With the lack of these vapor filled cavities, boiling of a dielectric liquid leads to high incipience superheats and accompanying temperature overshoots. Heater samples in this study were prepared by applying a thin Teflon (AF400, Dupont) coating on 1-cm2 smooth copper surfaces following common photolithography techniques. Matching size thick film resistors, attached onto the copper samples, generated heat and simulated high heat flux electronic devices. Tests investigated the heater samples featuring circular pattern sizes between 40–100 μm, and corresponding pitch sizes between 80–200 μm. Additionally, a plain, smooth copper surface was tested to obtain reference data. Based on data, hydrophobic patterned surfaces effectively eliminated the temperature overshoot at boiling incipience, and considerably improved nucleate boiling performance in terms of heat transfer coefficient and critical heat flux over the reference surface. Hydrophobic patterned surfaces therefore demonstrated a practical surface modification method for heat transfer enhancement in immersion cooling applications.
Forced Convective Drying of a Porous Cube: Non-Intrusive Temperature and Mass Transfer Measurements
Authors: Fanning Eoin , Persoons Tim , Murray Darina B.
Published: August 2016

The evolution of the mass transfer rate and temperature of a porous body in a convective drying process shows two main stages: A constant-drying rate period and a falling-drying rate period. This study investigates the simultaneous time evolution of moisture content and local surface temperature of a porous cube inside a rectangular flow channel for a range of air flow temperatures and Reynolds numbers. The moisture content is measured using a precision mass balance. Local surface temperature distribution is measured using a thermal imaging camera. In the constant-drying rate period, an average Nusselt number in the range 7.1 ≤ Nu ≤ 13.3 and an average Sherwood number of 4.7 ≤ Sh ≤ 6.0 are calculated for a Reynolds number range of 180 ≤ Re ≤ 595. Infrared thermography shows that the falling-drying rate period begins, the temperature distribution becomes non-uniform and approaches the temperature of the surroundings. This transition occurs first near the edges of the cube and, in particular, near the leading edge of the cube, as witnessed in previous studies.
Evaporation Momentum Force on a Bubble Under Asymmetric Temperature Conditions
Authors: Raghupathi Pruthvik A. , Kandlikar Satish G.
Published: August 2016

Recent literature claims that boiling performance can be significantly improved by using evaporation momentum force to control the trajectory of a bubble. This approach merits a detailed investigation into evaporation momentum force and its effect on bubble growth and bubble trajectory. In this paper an expression for evaporation momentum pressure experienced by a bubble is determined. This is incorporated into a well established bubble growth model (Mikic-Rohsenow) to evaluate the effect of evaporation momentum pressure on bubble growth rate. The effect of evaporation momentum force on a bubble growing in asymmetric temperature field is then studied and the resultant trajectory is evaluated. The results are compared with experimental data of bubble trajectory subjected to an asymmetric temperature condition. The final results suggest that the evaporation momentum pressure in the vicinity of contact line can significantly change the bubble trajectory, and surfaces designed to exploit this effect seem to be promising for boiling enhancement.
Effect of the Interface Mixing Layer on the Thermal Boundary Conductance of Metal-Organic Semiconductor Thin Film–Numerical Study by Lattice Boltzmann Method
Authors: Wang Xinyu , Chan Paddy K. L.
Published: August 2016

The interface mixing of metal-organic semiconductor layers plays a remarkable role in thermal transport in organic electronic devices. Here we apply the lattice Boltzmann method (LBM) to simulate the effect of the interface mixing on thermal boundary conductance (TBC) of Ag-pentacene and Ag-CuPc thin films. The spring constant-dependent transmission coefficient is considered in the simulation to investigate the effect of the interfacial bonding on TBC. The simulation result is compared with the experimental result of Ag-CuPc thin film obtained by other research group. By varying the thickness and composition of the intermixing layer, a significant variation of the thermal boundary conductance of the thin film is observed. The total thermal boundary conductance will increase with the spring constant per area. The increase of the thickness of the intermixing layer leads to the downward trend of the total thermal boundary conductance and it is attributed to the enhancement of the intrinsic thermal resistance of the intermixing layer. These findings suggest the interfacial bonding, thickness and composition of the metal-organic intermixing layer should be carefully controlled to achieve the desired thermal boundary conductance.
Influence of the Probe Laser Wavelength in Transient Reflectance Measurement of Gold
Authors: Guo Liang , Xu Xianfan
Published: August 2016

Transient reflectance of gold is measured with ultrafast spectroscopy by tunable probe wavelength. The influence of the probe wavelength on the signal is analyzed. It is found that when probed around 490 nm the signal is most sensitive to electron excitation and there is a simple linear relation between the reflectance change and the electron temperature change after sufficiently weak excitation. The two-temperature model is applied to calculate the electron-phonon coupling factor by fitting the transient reflectance signal.
Frictional Pressure Drop Correlations for Single-Phase Flow, Condensation and Evaporation in Microfin Tubes
Authors: Wu Zan , Sundén Bengt
Published: August 2016

Experimental single-phase, condensation and evaporation (flow boiling) pressure drop data from the literature and our previous studies were collected to evaluate previous frictional pressure drop correlations for horizontal microfin tubes of different geometries. The modified Ravigururajan and Bergles correlation, by adopting the Churchill model to calculate the smooth-tube friction factor and by using the hydraulic diameter in the Reynolds number, can predict single-phase turbulent frictional pressure drop data relatively well. Eleven pressure drop correlations were evaluated by the collected database for condensation and evaporation. Correlations originally developed for condensation and evaporation in smooth tubes can be suitable for microfin tubes if the friction factors in the correlations were calculated by the Churchill model to include microfin effects. The three most accurate correlations were recommended for condensation and evaporation in microfin tubes, respectively. The Cavallini et al. correlation and the modified Friedel correlation can give good predictions for both condensation and evaporation. However, some inconsistencies were found, even for the recommended correlations.
Transient Exergetic Efficiency of a Forced Convection Drying Process With and Without Electrohydrodynamic (EHD) Enhancement
Authors: Bardy Erik , Hamdi Merouane , Havet Michel , Rouaud Olivier
Published: August 2016

Electrohydrodynamic (EHD) drying is a novel drying method used to enhance forced convective drying by using a wire-electrode to create an electrostatic field. In this study, it was hypothesized that an EHD enhanced forced convective drying process will not only increase the drying rate, but also the exergetic efficiency over time. A transient exergetic efficiency was defined as the ratio of the exergy use rate in the removing of moisture from the drying product, to the exergy rate of the drying air supplied. In the case of EHD enhanced forced convection, the exergy rate supplied by the wire electrode was also accounted for. Forced convection drying experiments were run on a test specimen simulating a food product (methylcellulose gel) using an air flow channel with and without EHD enhancement with varying air flow velocities. Initial results show that the moisutre loss rate of the methylcellulose gel increased with the application of the electrostatic field. In addition, for low velocities, the exergetic efficiency of EHD enhanced forced convection was higher for the first few hours of drying as compared to conventional forced convection. The exergetic efficiency of both conventional and EHD enhanced forced convection converged at greater air flow velocities.
Topology Optimization for Heat Conduction Applications
Authors: Vadakkepatt Ajay , Trembacki Bradley L. , Mathur Sanjay , Murthy Jayathi Y.
Published: August 2016

The paper describes a topology optimization procedure to obtain optimal structures which maximize a chosen quantity of interest (QoI). Conduction heat transfer is assumed to govern the underlying physics. The numerical solution is performed using a finite volume formulation. The computational domain is divided into structured quadrilateral or hexahedral cells. Associated with each cell is a design variable that is intended to be driven to a binary value of either 0 or 1. The binary value determines which of two materials fill the cell. Thus the optimization problem seeks to find a structure, i.e., a spatial distribution of the design variable that maximizes a global QoI under specified constraints. A gradient-based optimization technique is developed within the framework of the finite volume formulation. We demonstrate the efficacy of the technique using a variety of test cases specifically for conduction heat transfer applications. The underlying procedure is, however, applicable to more general problems involving fluid flow and convective thermal transport as well as other physics.