Design Of Cooling Channels Research Articles

연소실 냉각채널 설계를 위한 1차원 열 해석 기법 확립 및 검증

연소실 냉각채널 설계를 위한 1차원 열 해석 기법 확립 및 검증

Advantages of Additive Technologies Usage in Design of Cooling Channels

Main aim of this paper is to analyze the thermal behavior of different cooling channels and to describe advantages of manufacturing of a mold with these channels using a 3D printer instead of drilling machines. This work was primarily done by the usage of virtual simulation. Validation of thermal simulations was performed by usage of simple analytical solution. A simple model of molded brick was designed to analyze the cooling time and the temperature distribution in the mold when changing the cross section of the cooling channels. Three types of different rectangular cross-sections and one circular were chosen. All of them have the same area. The cooling channel with circular cross section was positioned closer to the part in next design and influence of this change was analyzed. Last tested configuration is conformal cooling channel with a channel path twice longer. It is obvious, that most suitable configuration of cooling channels is combination of conformal design with rectangular shape as close as possible to plastic part.

Thermo-fluid Topology Optimization and Experimental Study of Conformal Cooling Channels for 3D Printed Plastic Injection Molds

Abstract With the advent of additive manufacturing, innovative design methods, such as network-based techniques, and structural topology optimization have been used to generate complex and highly efficient cooling systems in recent years. However, methods that incorporate coupled thermal and fluid analysis remain scarce. In this paper, a coupled thermal-fluid topology optimization algorithm is introduced for the design of conformal cooling channels. The problem is formulated based on a coupling of Navier- Stokes equations and convection-diffusion equation. The problem is solved by gradient-based optimization after analytical sensitivity derived using adjoint method. With this method, the channel position problem is replaced to a material distribution problem. The material distribution directly depends on the effect of flow resistance, heat conduction, natural and forced convection. The algorithm leads to a two-dimensional conceptual design having optimal heat transfer and balanced flow, which is further transformed into three-dimensional cooling channel design. Here, a comprehensive study is presented, starting from design, simulation, 3D printing process and experimental testing of an injection mold with conformal cooling channels in industrial production environment. A traditional mold model is provided by an industrial collaborator. To enhance the overall thermo-fluid performance of the mold and improve final product quality, a redesign of this mold core is done with conformal cooling channels inside. The final design is 3D printed in pre-alloyed tool-steel powder Maraging Steel using Truprint 3000 metal 3D printing machine. The printed core required some heat treatment and finishing processes and added features to be incorporated to make it production ready. Once all the preparation was complete, the core was tested experimentally in a multicavity injection molding machine in real industrial environment at our industrial partner’s production facility. This paper describes all the steps starting from design, analysis, die 3D printing and finally ending at final experimental testing, as well as recommendations for tool designer and injection molding industry to implement additive manufacturing for their benefit. This paper is not just focused on a specific aspect such as design, simulation or manufacturing, but rather a comprehensive paper presenting a case study on implementation of topology optimization and additive manufacturing in real life industrial production scenario.

연료 고온물성을 고려한 초음속 연소기 재생냉각 유로 설계

연료 고온물성을 고려한 초음속 연소기 재생냉각 유로 설계

The Thermal Effect of Variate Cross-Sectional Profile on Conformal Cooling Channels in Plastic Injection Moulding

Cooling system is an important role in designing a productive plastic injection moulding (PIM). The selection of geometry and layout for plastic injection moulding cooling channels strongly influences the cooling performance such as cooling time and thermal distribution that leads to shrinkage and warpage. This paper presents the study to determine the best cooling channel layout and cross-sectional profile which include circular straight drilled cooling channels, circular conformal cooling channels, square shape conformal cooling channels, elliptical conformal cooling channels and diamond conformal cooling channels. The cooling time and thermal distribution were simulated by Moldflow Insight (MFI) software. Results are presented based on ejection time and temperature variation by using transient analysis in MFI. The results found the best cross-sectional of cooling channels indicated by square shape conformal cooling channels, compare to others due to the shortest cooling time that recorded from simulation. The conformal cooling channel layout also resulted greater thermal distribution compared to straight drilled cooling channel design.

Impact of Flow Conditions in Cooling Channels on Thermal Cycling

In order to improve the set-up of industrial press hardening processes, companies and researchers are spending considerable efforts in the design and positioning of cooling channels. Following the increasing demands for modelling options, FEA software vendors have implemented corresponding features in their codes. Modeling cooling channels in FEA simulation facilitates a more accurate prediction of the location and dimensions of hot spots on the tool surface.The present simulation case study is based on a complete tool set up for a typical part. The FE-model of tool set-up, including a suitable cooling channel design, has been utilized for a study on press hardening of 22MnB5. The effectiveness of cooling channel design is determined by the flow conditions of the cooling media - here water. The flow rate and cooling media temperatures are the parameters with most influence on the thermal behavior of the tool. The impact of variations in these parameters on the final surface temperature distribution on tools, and the ramp-up of this distribution to thermal steady state, are the subject of this study. Beyond tool temperature distribution, the impact of the above parameters on the quality of produced parts is assessed by evaluating typical part quality metrics: hardness, martensite volume fraction in the part’s microstructure, and thermal distortion.It is observed that due to the complexity of the press hardening process, the details of cooling channel flow conditions do not carry a direct and proportional impact on part quality outcomes. This observation clearly indicates that engineers can derive descriptions of the cooling channel flow conditions from easy-to-use analysis tools that are fully integrated with the simulation of the forming process, rather than resort to extended, time consuming “offline” flow computations. An analytical method for calculation of cooling channel flow conditions is also introduced by the authors.

Design of Conformal Cooling Channels Using Numerical Methods in a Metal Mold and Calculating Exergy Destruction in Channels

Shorter cycle times, better product quality and less product outage can be possible with faster cooling. But mold cooling channels can only be made in linear directions and limited forms via classical manufacturing methods. Therefore, it limits that performance of mold cooling. Developed in recent years additive manufacturing technologies are capable of building complex geometries and monoblock 3D products. With this technology it is possible to produce metal molds with conformal cooling channels in different forms and capable of qualified cooling. In this study, conformal cooling channels were designed in order to achieve optimum cooling in monoblock permanent mold. In this study, CFD (Computational Fluid Dynamic) analyses are performed to steady stead conditions for designed conformal cooling channels and classical cooling channel mold. Pressure drops, cooling channel outlet temperatures and exergy destructions are calculated depending on the flow velocity rate in channels. The numerical investigations of the cooling process have shown that approximately 5% higher cooling performance can be achieved with conformal cooling channels. However, the pressure drop in the conformal cooling is observed to be higher than classical cooling channel. In addition, exergy destruction in the conformal cooling channel is approximately 12% greater than the classical cooling channel.

Helical FOFO snake for initial six-dimensional cooling of muons

The helical FOFO snake six-dimensional muon ionization cooling channel design is presented which incorporates wedge absorbers in such a way that simultaneous cooling of both signs of muons is possible.

CFD Evaluation of Hot Stamping Die Cooling System

This paper presents the results of CFD analysis on a complex near optimized cooling channels of hot stamping die for automotive structural part. Near optimum design is acceptable since cooling channels design is limited by its machining constraints. The objective of this evaluation is thus to determine the efficiency the cooling system by monitoring its cooling rate during 8 seconds of the quenching process. The die and blank were modelled as 3D volume mesh in a closed position thus ignoring the blank history data prior to the stamping operation. Temperature distribution representing hardness of the simulated final part is compared with the actual stamped component. The same procedure was validated against another structural component of different cooling channel design. The results show temperature pattern after 8 seconds can be used to predict harness distribution of the final part, thus indicating the viability of this method to be used in cooling system design.

Heuristic design of U-shaped die cooling channel for producing ultra-high strength steel using hot press forming

This paper proposes an optimised cooling channel design for a U-shaped die in the hot sheet metal forming process using a heuristic method. Unlike in previous works, the parameters used in this study for optimising the cooling channel design not only consider the pitch between and diameter of cooling channels but also their distance from the tool surface and wall tool. The cooling channel design is optimised by coupling the heuristic method with finite element thermal and static analyses. The main factors to be considered in the optimisation include the highest heat transfer and the lowest stress that can be achieved by the optimum cooling channel die design. The optimum design was determined by conducting a simulation and was validated by conducting an experiment. The temperature distribution of the FEA model was at most 5% different from the experimental results. The optimum cooling channel design of hot press sheet metal forming can produce ultra-high strength steels which tensile strength and hardness are 51 and 83% greater than those of original boron steels. The heuristic method can also be applied to optimise the cooling channel die design for the production of ultra-high strength steels in the automotive manufacturing industry.

Conceptual Design of CFETR CS Model Coil Structure

In order to verify key techniques and manufacturing aspects of the central solenoid (CS) coil of the China fusion engineering test reactor (CFETR), the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) plan to develop a CS model coil. The conceptual design of the CS model coil of CFETR has been carried out by ASIPP. The CS model coil shall produce a 12-T peak field in the bore of the magnet. The maximum magnetic field change rate is 1.5 T/s. The designed operating current is 47.65 kA. The CFETR CS model coil structure design mainly includes coil winding design, buffer zone design, preload structure design, coil joints and joint supports design, and liquid helium cooling channels design. This paper presents the conceptual design of CFETR CS model coil structure based on electromagnetic design and optimization.

Thermal Comparison of Conventional and Conformal Cooling Channel Designs for a Non-Constant Thickness Screw Cap

Complex parts are manufactured with high production rates using plastic injection. Defects in injection moulded parts are typically caused by non-uniform cooling. The design of cooling channels is a key step in the mould tool design process. Laser sintering allows for the direct fabrication at reasonable price, complex 3D tools with integrated cooling channels without the need of fixtures. This technique allows the designer to optimise the position of cooling channels relative to the heat source. This paper presents a simulation study for a non-constant thickness threaded screw cap. Results comparing conventional to conformal cooling channel show that the range between the highest and the lowest part surface temperatures is reduced by 18.8%. On the other hand, there is only a decrease of 3.9% for the maximum temperature in the interior of the threaded screw cap. Conformal cooling using laser sintering in tool manufacturing achieves an improved heat transfer leading to a better part quality.

Investigation on the transferability of algorithms for the numerical optimization of cooling channel design in injection molding on metal gravity die casting

AbstractThe thermal mold design and the identification of a proper cooling channel design are primordial steps in the development of complex molds for injection molding. In order to find a suitable cooling channel system, a lot of effort is needed to avoid part warpage after solidification. In current research, a simulative procedure to optimize the cooling channel layout iteratively is being developed at the Institute of Plastics Processing. These algorithms are transferred to the metal gravity die casting process, which has several similar requirements to the mold. Effectively, the simulation is simplified to a heat conduction problem. Instead of water, high temperature resistant oil is deployed and the casted material is a A356 aluminum alloy instead of semi‐crystalline plastics. The algorithm is adapted to these changed boundary conditions and the calculation of the optimized heat distribution is performed. Aim of this procedure is the construction of a mold producing parts with less warpage than a conventional mold.

Front End for a neutrino factory or muon collider

A neutrino factory or muon collider requires the capture and cooling of a large number of muons. Scenarios for capture, bunching, phase-energy rotation and initial cooling of μ 's produced from a proton source target have been developed, initially for neutrino factory scenarios. They require a drift section from the target, a bunching section and a φ -δ E rotation section leading into the cooling channel. Important concerns are rf limitations within the focusing magnetic fields and large losses in the transport. The currently preferred cooling channel design is an “HFOFO Snake” configuration that cools both μ+ and μ− transversely and longitudinally. The status of the design is presented and variations are discussed.

A “poor man’s approach” to topology optimization of cooling channels based on a Darcy flow model

A topology optimization methodology for optimizing cooling channels using an approximate but low-cost flow and heat transfer model is presented. The fluid flow is modeled using the Darcy model, which is a linear problem that can be solved very efficiently compared to the Navier–Stokes equations. The obtained fluid velocity is subsequently used in a stabilized convection–diffusion heat transfer model to calculate the temperature distribution. The governing equations are cast in a monolithic form such that both the solid and fluid can be modeled using a single equation set. The material properties: permeability, conductivity, density and specific heat capacity are interpolated using the Solid Isotropic Material with Penalization (SIMP) scheme. Manufacturable cooling-channel designs with clear topologies are obtained with the help of a pressure drop constraint and a geometric length-scale constraint. Several numerical examples demonstrate the applicability of this approach. Verification studies with a full turbulence model show that, although the equivalent model has limitations in yielding a perfect realistic velocity field, it generally provides well-performing cooling channel designs.

Press-Hardening Simulation - the next Level of Maturity

Press hardening has been fully established in the automotive industry during the last years. Forming simulation is an important tool to make the whole potential of press hardening available in both, the mass production and further developments. One of the usual simulation packages is AutoForm. It has been known as a reliable software tool for the sheet metal forming application area as well as for the press hardening for years. AutoForm-Thermo Solverplus supports direct and indirect hot forming, which are followed by quenching and cooling processes. It takes into account phase transformation during quenching and thermal distortion after cooling. The recent version AutoFormplus R7 brings further advances in process modeling for hot forming as this release allows users to take into account cooling channels. Based on this, the heat conduction in tools can be calculated. Cooling channel modelling affects press hardening simulation in two ways: it can be used to optimize the cooling channel design in the press hardening tools and it increases the accuracy level of the simulation in general. The resulting benefits coming from these new features will be presented in this paper; based on a B-pillar which was produced with direct press-hardening process.

Application and Design of Multi-Impingement Cooling Channel in Turbine Blade Trail Edge

Abstract The numerical simulations are used to conduct the comparative study of pin-fins cooling channel and multi-impingement cooling channel on the heat transfer and flow, and to design the multi-impingement channel through the parameters of impinging distance and impingement-jet-plate thickness. The Reynolds number ranges from 1e4 to 6e4. The dimensionless impinging distance is 0.60, 1.68, 2.76, respectively, and the dimensionless impinging-jet-thickness is 0.5, 1.0, 1.5, respectively. The endwall surface, pin-fins surface, impinging-jet-plate surface are the three object surfaces to investigate the channel heat transfer performance. The heat transfer coefficient h $h$ and augmentation factor N u / N u 0 $Nu/N{u_0}$ are selected to measure the surface heat transfer, and the friction coefficient f $f$ is chosen to evaluate the channel flow characteristics. The impinging-jet-plate surface owns higher heat transfer coefficient and larger area than pin-fins surface, which are the main reasons to improve the heat transfer performance of multi-impingement cooling channel. Reducing the impinging distance can improve the endwall surface heat transfer obviously and enhance impingement plate surface heat transfer to some extent, decreasing the thickness of impinging-jet-plate can significantly increase its own heat transfer coefficient, which both all increase the cooling air flow loss.

Modeling the Effect of the Design of Air Cooling Channels on the Thermal Behavior of a Lithium-Ion Battery Module

The lithium-ion battery (LIB) is one of the preferred candidates for electric vehicle (EV) and hybrid electric vehicle (HEV) applications due to its outstanding characteristics such as high energy density, modular scalability, long cycle life, and low self-discharge rate among others. In a battery module for EV applications, an uneven temperature distribution in the module can be created depending on the operating conditions and the types of thermal management. Uneven temperature distribution in a module could cause an electrical imbalance and thus lead to the lower performance and shorter life of battery. Therefore, it is important to calculate accurately the uneven temperature distribution in a battery module in order to achieve the optimum performance and long life of the battery module. In this work, a three-dimensional modeling is performed to investigate the effects of the design of air cooling channels on the thermal behavior of an LIB module. Thermal conductivities of various compartments of the battery are estimated based on the equivalent network of parallel/series thermal resistances of battery components. Heat generation rate in an LIB cell is calculated by using the modeling results of the potential and current density distributions of a battery cell. Fig. 1 shows the schematic diagram of the battery module composed of 24 cells with two types of air cooling channels. The average temperatures from the experimental measurement for the LIB module for US06 cycle profile are compared with those predicted by the modeling in Fig.2. Figure 1

Characterization of the cooling channels of First Wall Mock-up dedicated to the HCPB TBM qualification

The First Wall (FW) of the EU Helium Cooled Pebble Bed (HCPB) Test Blanket Module (TBM) faces the fusion plasma and experiences high heat fluxes; therefore its cooling channels design is a key R&D task for qualifying the HCPB TBM for the fusion reactors ITER and DEMO. Within the manufacturing and qualification activities performed in KIT for the HCPB TBM, a First Wall Mock-up (FWM) was designed and manufactured. The objective of this study is to characterize the hydrodynamic behaviour of the FWM cooling channels by investigating the coolant pressure drop for each channel. The FWM has a shape of rectangular prism (710mm×405mm×45mm) with 10 U-shaped cooling channels which have a square cross section (15mm×15mm) with rounded corners of 4mm radius. The FWM was integrated into a gas loop that has the relevant instruments and piping system for measuring and controlling the air (6bar abs.) flow parameters. This paper presents experimental measurements of the pressure drop across the FWM cooling channels. The present results support the qualification of the HCPB TBM mock-ups which will be tested in the Helium Loop Karlsruhe (HELOKA) facility with fusion-relevant heat flux and helium cooling.

Thermal Analysis for Conformal Cooling Channel

Design of cooling channel is one of limitation in injection moldingprocess. The molding process involves in the phases like filling, cooling and ejection. Cooling phase is one of the critical phase to get quality and cycle time of part. Generally straight line drilled hole process is used in most of the industries for the mould, where uniform cooling is not achieved. Non uniform cooling or cycle time-consuming would results in design defects of cooling channel. To over conventional cooling channels, a concept of conformal cooling channel is introduced in which the uniform cooling of the mould takes place. In this paper various cooling channel designs were made to optimization of cooling effect and to minimize the cooling defects in injection molding process. Finite element analysis is used to analyze thermal stresses in the mould surface geometry generated around the mould. Taguchi method is used to obtain the optimum design of cooling channel from various designs