Steady-state Thermal Analysis Research Articles

Computational investigation of plasma arc welding process for aluminium alloys

Thermal stress is a very common phenomenon that occurs at the welded joint. Determination of the same at the joint is however difficult due to inhomogeneity of the weld joint metals and spreading of heat to the surroundings from the Heat Affected Zone (HAZ). Thermal stress induced at the welded joint changes the microstructure of grains which affects the mechanical properties of the welded material. Due to this, cracks may appear in the joint leading to failure of the weld. In the present study, three-dimensional model of two types of welded joint, i.e., Tee Joint and lap joint of two plates having dimensions 100 mm × 75 mm × 5 mm are prepared using ANSYS Workbench 2020 R2. Hex dominant meshing is chosen in order to have clear picture of the spread of temperature over the entire region. The change of Residual stress with variation of welding current and keeping welding voltage constant is also observed for weld joint made of Aluminium Alloy. In this study, conduct steady-state thermal analysis and structural analysis on an aluminium alloy 6063 to assess von Mises stress, von Mises strain, and deformation distribution induced by heating. Evaluate various welding joints to identify the most effective technique.

Simulation analysis of thermal insulation performance of diesel engine piston based on PEO and La2Zr2O7 thermal barrier coating

In this research, we explored the application of ‘thermal swing’ thermal barrier coatings (TBCs) in diesel engines, aiming to surpass the performance of conventional TBCs. Traditional TBCs often suffer from limitations like consistently high surface temperatures and a delayed response to sudden variations in cylinder temperatures, which adversely impact engine efficiency. To overcome these challenges, plasma electrolytic oxidation (PEO) technology was employed to engineer TBCs with the sought-after ‘thermal swing’ feature. Comparative simulations were conducted to assess the thermal characteristics of PEO coatings on pistons, in contrast to standard La2Zr2O7 coatings. The steady-state thermal analysis revealed that PEO coatings maintained a lower peak temperature compared to La2Zr2O7 coatings under similar thermal insulation conditions, indicating a superior ability of the PEO coatings in heat dissipation and in sustaining lower surface temperatures.In the transient thermal analysis, focusing on temporal temperature variations, the PEO coatings exhibited a markedly quicker and more robust response to cylinder temperature fluctuations. This indicates that PEO coatings are highly effective in adapting swiftly to temperature changes, thereby contributing to enhanced engine performance. Additionally, the PEO coating demonstrated a notable reduction in the end temperature (TE), which is crucial for mitigating the heating effect on intake gas, in comparison to La2Zr2O7 coatings with equivalent thermal insulation properties. However, it was observed that this advantage significantly decreased when the PEO coating thickness surpassed 0.3 mm. Drawing from these observations, it is concluded that PEO coatings hold several thermal advantages over La2Zr2O7 coatings, particularly in terms of thermal load management and responsiveness to in-cylinder temperature shifts. These benefits are most pronounced when the PEO coating maintains a thickness below 0.3 mm.

Design, Static Structural and a Steady State Thermal Analysis of Aluminum Composite Piston

The aim of this project is to increase the life and to analyze the various characteristics of composite piston that is strength, weight, thermal conductivity, density, thermal stress and specific heat. Piston is the basic component of the automobile engine. The modified design of the composite piston in this project is compared with existing piston to analyze the Mean Time Between Maintenance. Now-a-days the pistons are made up of aluminium silicon alloy which expands enormously due to generation of heat in the piston. This will affect clearance volume and insufficient clearance can cause the piston to seize in the cylinder. Hence an alternative composite material (Al) which will reduce the expansion. These composite piston are mainly applicable in receprocating engines, pumps and marine ships. The temperature distribution of the piston will be analyzed with the help of ANSYS software. In this analysis, the rate of heat transfer and thermal stress are evaluated for different composition materials. Key Words: composite piston, aluminum silicon alloy, thermal stress, thermal distribution

Comparative analysis of material for flat & dome top piston for SI engine using ansys

Compared to other areas of the IC engine, the working condition of piston attracts the most attention rather than any part in IC engine due to its complexity. Pistons have undergone many significant material and topographic changes since their first industrial introduction to overcome these working conditions. It is being said that electric vehicles will take over the world, but until the Lithium-ion battery remains, there will always be a shortage for batteries. Taking this as an assumption and the fact that carbon neutral fuel is currently in development, our goal is to make the piston lighter and more durable to make it future ready. In this research article, our objective is to substantiate and analyze the stress distribution of the piston with various [1] piston crown designs, namely, [1] flat top and dome top; integrated with various synthetic and alloy materials, namely, Titanium alloy, [2] Aluminum alloy, [3] Super magnesium, and [4] 3D Graphene. [5] Static Structural and Steady state thermal analysis is performed on these pistons using ANSYS R2 2022 software, while designing is performed on AutoCAD 2020 software. This article presents and analyses [5] thermal stress analysis and damages due to pressure application. Results are displayed comparing based on [5,6,7] total deformation, Von-mises strain, Von-mises stress, strain energy, normal elastic strain, normal stress, total heat flux and directional heat flux. Result is concluded by comparing to find the most preferable material for the piston in an engine. The preference is given based upon weight reduction, strength, and future scope of the material.

Open-source MBSE workflow for automated spacecraft thermal analyses from a system model IAC-22,D1,4B,2,x70017

Model-based systems engineering (MBSE) is an emerging methodology not only in the field of spacecraft systems engineering. The key objective is to store the whole system design in one single source of truth system model. The continuously maintained and customizable open-source MBSE tool Virtual Satellite developed by German Aerospace Center (DLR) offers a framework for storing such a system model. Since the open-source 3D computer aided design (CAD) software FreeCAD has a dedicated Virtual Satellite workbench for importing the 3D model file generated by Virtual Satellite, it is possible to export the 3D model from Virtual Satellite, apply changes to it in FreeCAD, and afterwards reimport it in Virtual Satellite. This paper presents a workflow implementation to conduct automated steady-state and transient thermal analyses using the Virtual Satellite system model as a basis, utilizing the aforementioned features. Part of this effort was to extend Virtual Satellite by thermal modeling capabilities, such as material parameters, surface characteristics, thermal interfaces, boundary conditions and further relevant aspects. With custom Java applications, so-called “Apps”, all aspects of the system model relevant for a thermal analysis are exported from Virtual Satellite and written to accordingly generated text files. Moreover, the before described 3D model export is used to export the model to FreeCAD. The FreeCAD Python console, in combination with the finite element method (FEM) workbench, is used to create a script that executes meshing, application of the boundary and initial conditions, as well as identification of contacts between parts and application of the specified contact conductance values. The obtained files form a complete thermal model and can be fed directly into the open-source FEM software CalculiX for executing the thermal analysis. Then, the result can be processed by an additional Virtual Satellite App. To account for the space thermal environment an additional feature was added to the FreeCAD script. The feature uses orbit information obtained from external mission analysis tools to calculate the approximate combined heat load from Sun, Earth infrared, and albedo radiation at each time point in the specified simulation time interval. This new workflow allows to execute quick thermal analyses at an early design stage and therefore opens new opportunities in the evaluation of different system designs, as early as in a concurrent engineering study. Configuration parameters are provided that also allow more sophisticated analyses in later development phases, such as custom mesh definition and local mesh refinement.

Comprehensive feasibility assessment of cycle length extension for CNPGS Unit-3

The core cycle length is crucial parameter for effective and economic operation of a nuclear power plant. Nuclear industry has great emphasis on improving the feasibility and sustainability of nuclear power generation. The cost of the electricity can be reduced by increasing the cycle length without violating the safety margins. Various methods and strategies have been examined to extend a Pressurized Water Reactor (PWR) core cycle length with optimized loading patterns. The objective of this work is to analyse the feasibility of the system to extend the cycle length of Chashma Nuclear Power Generating Station (CNPGS) unit-3, currently operating in Pakistan from 12 months to ∼18 months. To achieve the objective, fuel enrichment is increased from 3.4% to 4.1% with Gd2O3 as burnable poisons to suppress the excess reactivity. The multi-cycle analyses showed promising results and the core cycle length has been extended to ∼18-month for CNPGS unit-3 keeping power peaking factor, temperature coefficients and discharge burnup within design limits. The method can be confidently applied at any cycle of the power plant. Additionally, fuel and moderator temperatures at average and hot channels at beginning of life (BOL) and the end of life (EOL) are predicted using the 1-D steady state thermal hydraulic analysis. The peak to average temperatures at BOL and EOL are found well below the reference value (1.6875).

Directly irradiated liquid metal film in an ultra-high temperature solar cavity receiver. Part 2: Coupled CFD and radiation analysis

A novel solar cavity receiver was proposed in Part 1 to facilitate operation at ultra-high temperatures (>1300 K). The concept featured enclosing a directly irradiated liquid metal film inside a window-sealed cavity containing an inert protective fluid. The receiver’s technical performance was evaluated using a quasi-steady-state analysis based on various assumptions, which were used to enable analytical modelling of the involved energy transfer mechanisms. This paper describes a Computational Fluid Dynamics (CFD) solution developed to verify the conclusions of Part 1 and furtherly investigate the technical performance of the proposed receiver. The solution combined the Volume Of Fluid (VOF) and Discrete Ordinates Model (DOM) methods to simulate the volumetric radiation absorption by the liquid metal film while accounted for the transient flow developments of the gravity-driven film and buoyancy-driven cavity fluid. Analytical models were verified, showing improved performance for the absorptive cavity configuration. Film flow disintegration was mitigated by using surface corrugations, which were found to significantly influence the fluid dynamics and heat transfer performance of the receiver. Finally, a steady-state thermal analysis was presented for the proposed ceramic window, which indicated that active cooling is indispensable for protecting the window against thermo-mechanical fatigue.

Neutronic and thermal analysis of heat pipe cooled graphite moderated micro reactor

Heat pipe micro reactors are drawing a lot of interest lately due to their distinct features, including the elimination of moving parts required for transferring the heat, as they do so passively through heat pipes, combined with the ability of such reactors to provide energy to remote locations. This present study introduces a proposed design for heat pipe cooled graphite moderated micro reactor suitable for remote locations and space applications. The main requirements of the design include long core lifetime, two shutdown mechanisms, uniform power distribution, and strong negative temperature coefficient. Neutronic calculations were performed using MCNP 6.2 code. Criticality analysis demonstrated the ability of both control devices incorporated in the design to independently control and shutdown the reactor. Calculations of the flux and power distribution showed that, for a thermal power of 0.25 MW, the maximum flux at mid-plane of the reactor is in the order of 1012n/(cm2·s), while radial and axial power peaking factors were found to be 1.2 and 1.13, respectively. The results also showed that the reactor has an overall negative temperature coefficient. Additionally, burnup calculations were carried out to calculate the core lifetime which was estimated to be more than 70 years. A preliminary steady-state thermal analysis was conducted for the reactor using ANSYS FLUENT, assuming 1/12th symmetry. The obtained temperature distribution of the reactor showed that the operating temperatures are within the accepted limits where the highest temperature reached in the fuel was 1074 K. Furthermore, soft coupling of MCNP and ANSYS FLUENT was conducted through an iterative process of performing neutronic and thermal simulation using updated results for the temperatures and power distributions in each iteration.

Design and analysis of horizontal crystallizer for agro-chemical industries

Crystallization is a process in which hot solution is allowed to cool in a shell to form crystals at the end of the process. Crystallization is predominantly used in chemical industries. In most of the industries vertical crystallizer are used for continuous crystallization. The proposed project is horizontal crystallizer used for batch crystallization. In this project we have tried to solve problem wherein blades were subjected to impact load and produced a greater number of vibrations in the crystallizer, due to which blades were failing at the location where blades were connected to the shaft end because of more stresses. Also, the blades will be subjected to elevated temperature for some period. To solve this problem some research about various types of agitators is available. Designing of two types of blades those are single helical blades and double helical blades has been done. These blades will be suitable for mixing viscous solution and these blades works on the principle of shearing the solution and pushing it. These blades will produce fewer vibrations as compared to pedal blades used in the industries. Static structural analysis and Steady State Thermal Analysis on blades as well as on Shell has been done. The Stresses and deformation pattern are produced within safety limits. After performing the Design and Analysis of Shell and Blades, a model which has a capacity of 440 Litres has been fabricated and the results are interpreted. The fabricated crystallizer is implemented in the chemical industry which is providing better crystals as compared with the already in use crystallizer.

Design and analysis of 3-way catalytic converter using CFD

A catalytic converter is a device designed to decrease the levels of harmful pollutants emitted by internal combustion engines. These converters are commonly used in automotive exhaust systems. Different fluids, such as carbon dioxide, ethane, and nitrogen, are employed for various purposes. To perform steady-state thermal analysis, different materials like stainless steel are utilized. The catalytic converter, typically constructed from gray cast material, facilitates the conversion of CO, HC, and NOx emissions into CO2, H2O, N2, and O2. This study involves the utilization of Computational Fluid Dynamics (CFD) analysis on iron and aluminum catalytic converters. Additionally, a thermal study is conducted to determine suitable materials for catalytic converter manufacturing. The CATIA (Computer Aided Three-dimensional Interactive Application) software is used for design purposes, while Ansys Workbench 16.0 is employed for analysis.

Research on the Performance of Recycled-Straw Insulating Concrete and Optimization Design of Matching Ratio

Construction solid waste and agricultural waste, as renewable resources, have gained increasing attention recently. This research aims to explore the mechanical and thermal properties of recycled-straw insulating concrete commonly made with construction waste and straw in northern Fujian, which can provide useful suggestions for the practical use of recycled-straw insulating concrete. The effects of recycled coarse aggregate, fly ash, and straw on the mechanical and thermal properties of recycled-straw insulating concrete were investigated by orthogonal tests. The results of the orthogonal tests were optimized by the total efficacy coefficient method to obtain the optimal mix ratio of recycled-straw insulating concrete. Combined with the finite element analysis software ANSYS Workbench, the heat transfer performance of the recycled-straw insulating concrete walls was analyzed to simulate the insulation performance of the walls. The compressive strength of the recycled-straw insulating concrete with the optimal ratio was found to be 30.93 MPa, and the thermal conductivity was 0.5051 W/(m·K). The steady-state thermal analysis of the recycled-straw insulating concrete wall and the plain concrete wall was carried out by finite element software, and the simulation results showed that the insulation performance of the recycled-straw insulating concrete walls was improved by 145% compared with the plain concrete wall. These results indicate that the recycled-straw insulating concrete wall has better thermal insulation performance and can be applied to building envelopes to save heating costs in winter and reduce carbon dioxide emissions, which has significant economic and environmental significance for areas with low outdoor temperatures in winter and long heating periods.

Front-Face RH Compatible Structure Design and Thermal Analysis for CFETR Divertor Dome

The China Fusion Engineering Test Reactor (CFETR) is a device developed to verify the engineering feasibility of a fusion reactor. For CFETR, the divertor is an important plasma-facing component, whose main function is to exclude impurities and remove plasma heat. In addition, the requirement for remote handling (RH) maintenance must be satisfied because of the level of radioactivity in the vacuum vessel after shutdown. The dome is an important component of the divertor, whose main function is to isolate impurity particles as well as to improve the ability of excluding particles. In the optional dome design, a hybrid divertor-blanket concept, a front-face RH compatible structure in plasma-facing units (PFUs), and a RH maintenance scheme for the main bolt are proposed. The vulnerable targets can be replaced directly and thus reduce the RH maintenance time. The dome needs to withstand the heat flux of 10 MW/m2 and nuclear heat in the condition of 1.5 GW of fusion power in the engineering design requirements. Because of the RH compatible structure, higher requirements are demanded for the design of the dome cooling system. In this study, the cooling system and the customized heat transfer structure of dome PFUs are designed to guarantee the maximum heat removal level. The steady-state thermal analysis shows that the cooling system fulfills the design requirements. The concept of the hybrid divertor-blanket and the front-face RH compatible structure for the divertor target have certain reference significance and value for the engineering design and RH maintenance research for the fusion reactor divertor in the future.

Effects of Varying Volume Fractions of SiO2 and Al2O3 on the Performance of Concentrated Photovoltaic System

Highly concentrated triple-junction solar cells (HCTJSCs) are cells that have diverse applications for power generation. Their electrical efficiency is almost 45%, which may be increased to 50% by the end of the year 2030. Despite their overwhelming ability to generate power, their efficiency is lower when utilized in a concentrated manner, which introduces a high-temperature surge, leading to a sudden drop in output power. In this study, the efficiency of a 10 mm × 10 mm multijunction solar cell (MJSC) was increased to almost 42% under the climatic conditions in Lahore, Pakistan. Active cooling was selected, where SiO2–water- and Al2O3–water-based nanofluids with varying volume fractions, ranging from 5% to 15% by volume, were used with a 0.001 kg/s mass flow rate. In addition, two- and three-layer microchannel heat sinks (MCHSs) with squared microchannels were designed to perform thermal management. Regarding the concentration ratio, 1500 suns were considered for 15 August at noon, with 805 W/m2 and 110 W/m2 direct and indirect radiation, respectively. A complete model including a triple-junction solar cell and allied assemblies was modeled in Solidworks software, followed by temperature profile generation in steady-state thermal analyses (SSTA). Thereafter, a coupling of SSTA and Ansys Fluent was made, in combination with the thermal management of the entire model, where the temperature of the TJSC was found to be 991 °C without active cooling, resulting in a decrease in electrical output. At 0.001 kg/s, the optimum average surface temperature (44.5 °C), electrical efficiency (41.97%), and temperature uniformity (16.47 °C) were achieved in the of MJSC with SiO2–water nanofluid with three layers of MCHS at a 15% volume fraction. Furthermore, the average outlet temperature of the Al2O3–water nanofluid at all volume fractions was high, between 29.53 °C and 31.83 °C, using the two-layer configuration. For the three-layer arrangement, the input and output temperatures of the working fluid were found to be the same at 25 °C.

TAŞIT FRENLEMESİ ESNASINDA OLUŞAN ISI TAŞINIMININ İNCELENMESİ

The brake system is the most significant active safety system that converts the vehicle's mechanical energy into heat energy based on the braking pair’s friction. The transfer of heat in the brake pair during braking occurs by conduction, convection, and radiation. In disc brakes, which are widely used today, the effect of the heat transfer coefficient, which continually changes with the disc's angular velocity on the cooling of the braking pairs is important. The change in heat convection coefficient can be calculated with a numerical approach. In this study, on disc temperature effect of heat convection coefficient and angular velocity has been examined with the finite element method using the experimental data in the SAE J2522 Comprehensive Brake Efficiency Test Standard, fading test procedure. Disc brake design has been designed in the SOLIDWORKS program, and analysis has been carried out using ANSYS 2020 R2 in steady-state thermal analysis. It has been determined that the cooling amounts at the initial of braking are higher than the cooling amounts at the end of braking, and the effect of cooling by convection in the reduction of the temperature difference at the end of braking compared to the initial state is between 91.22% and 91.74%.

A Simplified Thermal Analysis Model for Regeneratively Cooled Rocket Engine Thrust Chambers and Its Calibration with Experimental Data

An essential part of the design of a liquid rocket engine is the thermal analysis of the thrust chamber, which is a component whose operative life is limited by the maximum allowable wall temperature and heat flux. A simplified steady-state thermal analysis model for regeneratively cooled rocket engine thrust chambers is presented. The model is based on semi-empirical correlations for the hot-gas and coolant convective heat transfer and on an original multi-zone approach for the wall conduction. The hot-gas heat transfer is calibrated with experimental data taken from an additively manufactured water-cooled nozzle that is connected to a combustion chamber either fed with decomposed hydrogen peroxide or decomposed hydrogen peroxide and automotive diesel. The thrust chamber (i.e., combustion chamber and nozzle) is designed to produce about 450 N of thrust when operating with a chamber pressure of 11 bar. For this application, the calibrated model predicts the total wall heat transfer rate very accurately and the temperature distribution within the wall structure with an uncertainty of a few tens of kelvins. This level of accuracy can be considered more than adequate for the design, and generally for engineering-type thermal analysis, of similar thrust chambers.

Rolling Tires on the Flat Road: Thermo-Investigation with Changing Conditions through Numerical Simulation

A crucial material comprising a pneumatic tire is rubber. In general, the tire, or more specifically, the hysteresis effects brought on by the deformation of the part made of rubber during the procedure, heat up the part. In addition, the tire temperature depends on several factors, including the inflation pressure, automobile loading, car speed, road tire, the environmental conditions, and the tire geometry. This work focuses on using simulations to calculate the temperature and generated heat flow distributions of a rolling tire with constant velocity using the finite element method. For the sake of simplicity, it is assumed that the only components of the tire are rubber, body-ply, bead wire, and the rim. While the other components are believed to be made of a linear elastic material, the nonlinear mechanical behavior of the rubber is characterized by a Mooney–Rivlin model. Investigations are conducted into the combined effects of vehicle loads and inflation pressure. Hysteresis energy loss is used as a bridge to link the strain energy density to the heat source in rolling tires, and their temperature and heat flow distributions may be determined by steady-state thermal analysis. Thanks to the state-of-the-art computing method, the time required for connected 3D dynamic rolling tire simulations is reduced. The simulation outcomes demonstrate that the maximum temperature in this paper is attained with high weights, high velocities, and low inner inflated pressures. Overall, the maximum temperature is increased with the rise of all three variables. Moreover, the rise of the friction coefficient between the tread and road surface moves the high-temperature area towards the tread/sidewall connection area.

An Analysis of The Material and Design of an Exhaust Manifold for A Single-Cylinder Internal Combustion Engine

This study aims to find the best material for the manifold and improve airflow in the UniMAP Automotive Racing Team (uniART) exhaust manifold. The exhaust manifold is a part of the exhaust system that collects and delivers exhaust gases from the cylinder head to the exhaust outlet. The exhaust manifold’s design is significant to the engine performance. The current design and new designs of the exhaust manifold were modelled using SOLIDWORKS software. Stainless steel, cast iron and mild steel were chosen as materials for manifold and were studied by conducting the Steady-State Thermal analysis. The flow of the air in the manifold is analysed and evaluated in terms of pressure and velocity. The fluid flow and thermal analysis are simulated in Computational Fluid Dynamics analysis software known as ANSYS. Results of thermal analysis prove that Stainless steel is better than other materials since it has a high temperature difference and low heat flux. The results of fluid flow analysis were compared between the current design and new designs of the exhaust manifold. The outcome indicated that validated Design 2 has a higher velocity value at the outlet and lower pressure at inlets which improves the airflow in the exhaust manifold.

Thermal analysis on dome (Daylight system) with the help of aerogel

Natural daylight has many benefits, but bringing the light inside the deep interior is challenging work. It is not possible for the conventional window, but by using a light guide system, it is possible. The light guide system comes with both active and passive collectors. In this research paper, we have done the thermal analysis on the dome (daylight system) with the help of Aerogel daylight by using the dome as a passive collector. Dome has been used for vertical type light guide system. The main aim of the work is to reduce the temperature inside the tube and room, as the outside temperature is 38 degrees Celsius. As we know, the temperature inside the room is increased by the daylight system because there is no breakdown of heat that is trapped in the system; the heat that comes from the dome or collector is directly from the sun. As we know, the dome is made up of acrylic (Polymethyl-Methacrylate, or PMMA). The material has a thermal conductivity of 0.2085 W/m*K, so to breakdown the heat trapped inside the daylight system, we are using a material known as aerogel. The use of this material is due to its low thermal conductivity, which is 0.01 W/mK. Due to its highly insulating properties, aerogel is becoming one of the most promising materials for insulation, and the material is becoming more widespread. So we are taking layers of aerogel and applying them to the surface of the dome or collector, running the steady-state thermal analysis in Ansys Software, and studying the temperature effect on them. Also applying different layering sizes onto the dome.

Steady state thermal analysis of a porous fin with radially outwards fluid flow

Fins are used ubiquitously in engineering devices and systems for enhancement of heat transfer and energy storage. While traditional fins are made of non-porous materials, porous fins with natural convection porous flow orthogonal to the fin direction have also been studied. In contrast to these, there is a lack of work on porous fins in which the fluid flow may be along the direction of the fin. In such a fin, porosity may increase advective heat removal due to increased flow rate but may also impede conductive heat removal due to reduction in effective thermal conductivity. Due to these competing trade-offs, there is a need for comprehensive analysis of thermal performance of such a porous fin. This work derives a solution for the steady-state temperature distribution in a porous fin with advection along the fin direction. It is shown that temperature distribution in such a porous fin is governed by a convection-diffusion-reaction equation. A solution for the temperature distribution is derived in the form of modified Bessel functions of non-zero order. Two distinct fin performance parameters are defined and derived in order to characterize porous fin performance. It is found that thermal properties of the fin as well as ambient convective conditions strongly impact the relationship between fin porosity and fin performance. While in some cases, it is found that an optimum porosity exists that maximizes heat removal, in other cases, the use of a porous fin is found to be not desirable at all. The analysis presented here helps fully understand these trade-offs, and provides useful guidelines for porous fin design for maximum heat removal.

Numerical Investigation on Heat Flux Variation in Fuel Bundle Over Fully Voided Concentric Channel of IPHWR Under Severe Accidental Scenario

Abstract A steady-state thermal analysis is performed on a fully voided channel of an Indian pressurized heavy water reactor (IPHWR) by providing variable heat flux inputs of 800 W/m2, 1500 W/m2, 2500 W/m2, 3500 W/m2, and 4500 W/m2 for evaluating the numerical results of temperature distributions in pressure tube (PT) and calandria tube (CT) at concentric scenarios using a numerical approach. The top to bottom temperature difference of PT and CT is found to be 0.57% and 3.31%, respectively, for 800 W/m2 input heat flux, and this variation decreases to 0.015% and 0.05%, respectively, for 4500 W/m2 input heat flux, thus pointing out that increasing the heat flux leads to the decreased top to bottom temperature difference. Also, the temperature distribution pattern is found to be similar for all the input heat fluxes, and for a particular heat flux, the change in circumferential temperature is found to be negligible. The boiling phenomenon starts at 2500 W/m2, and the volume fraction of moderator vapor increases as the heat flux is increased, the average density of moderators inside the enclosure decreases, and continuous variation in film thickness is also observed with respect to time for a particular heat flux value. The results also showed that the moderator acted as an effective heat sink for higher heat input rates.