scholarly journals Increasing the safety against scuffing of additive manufactured gear wheels by internal cooling channels

2021 ◽  
Author(s):  
Hans-Jörg Dennig ◽  
Livia Zumofen ◽  
Daniel Stierli ◽  
Andreas Kirchheim ◽  
Simon Winterberg
Keyword(s):  
Cooling System ◽  
Research Centre ◽  
Internal Cooling ◽  
Layer By Layer ◽  
Powder Bed ◽  
Cooling Channels ◽  
Material Development ◽  
Cooling Strategy ◽  
Design And Manufacturing ◽  
Gear Wheels

AbstractThe layer-by-layer principle of the additive manufacturing (AM) technology of Laser-Powder-Bed-Fusion (LPBF) creates new opportunities in the design and manufacturing of efficient gear components. For example, integrating a cooling system can increase the safety against scuffing or reduce the amount of required lubrication and thus the splashing losses. Quenched and tempered steels or case-hardened steels are commonly used in the fabrication of gear components. However, the availability of these alloys for LPBF processing is still limited. The development of suitable LPBF metal gears (with a Gear Research Centre (FZG) type A geometry) out of quenched and tempered 30CrNiMo8 steel with internal cooling channels shows the possibility of significantly increasing the safety factor against scuffing. This work includes the development of a suitable cooling strategy, material development, the setup of a suitable test infrastructure and the analysis of the LPBF gears tested for scuffing.

scholarly journals Influence of Microstructure and Defects on Mechanical Properties of AISI H13 Manufactured by Electron Beam Powder Bed Fusion

2021 ◽  
Author(s):  
Moritz Kahlert ◽  
Florian Brenne ◽  
Malte Vollmer ◽  
Thomas Niendorf
Keyword(s):  
Mechanical Properties ◽  
Electron Beam ◽  
Additive Manufacturing ◽  
Internal Cooling ◽  
Layer By Layer ◽  
Powder Bed Fusion ◽  
Powder Bed ◽  
Cooling Channels ◽  
Fine Grained ◽  
Aisi H13

AbstractElectron beam powder bed fusion (E-PBF) is a well-known additive manufacturing process. Components are realized based on layer-by-layer melting of metal powder. Due to the high degree of design freedom, additive manufacturing came into focus of tooling industry, especially for tools with sophisticated internal cooling channels. The present work focuses on the relationships between processing, microstructure evolution, chemical composition and mechanical properties of a high alloyed tool steel AISI H13 (1.2344, X40CrMoV5-1) processed by E-PBF. The specimens are free of cracks, however, lack of fusion defects are found upon use of non-optimized parameters finally affecting the mechanical properties detrimentally. Specimens built based on suitable parameters show a relatively fine grained bainitic/martensitic microstructure, finally resulting in a high ultimate strength and an even slightly higher failure strain compared to conventionally processed and heat treated AISI H13.

Study of the Effect of Turbulence Promoters in Circular Cooling Channels

2009 ◽  
Author(s):  
N. Cristobal Uzarraga-Rodriguez ◽  
Armando Gallegos-Mun˜oz ◽  
J. Cuauhtemoc Rubio-Arana ◽  
Alfonso Campos-Amezcua ◽  
Mazur Zdzislaw
Keyword(s):  
Pressure Drop ◽  
Aspect Ratio ◽  
Cooling System ◽  
Circular Cross Section ◽  
The Body ◽  
Internal Cooling ◽  
Combustion Gases ◽  
Cooling Channels ◽  
Cooling Effects ◽  
Volume Method

A numerical analysis of a gas turbine first stage bucket with internal cooling (model MS7001E) is presented. The internal cooling system consists of 13 cylindrical channels with turbulent promoters (ribs), which are implemented in order to achieve temperature decrements inside the body blade. Three different geometrics (square, triangular and semi-circular cross-section) are studied. Each configuration is analyzed having full or half ribs. These are placed inside the cooling channels. The effects generated by the aspect ratio variation between rib pitch and rib height (P/e), for a constant aspect ratio given by ribs height and hydraulic diameter (e/Dh) are considered. The numerical simulation was developed using finite volume method, by means of commercial software based on computational fluid dynamics (CFD). Each one of the models generated for each study case was built in a 3D model, including the platform and airfoil of the blade. The models consider the effects generated by the hot combustion gases are flowing around the blade and the coolant flow is flowing inside the cooling channels. The study includes the solution of the conjugate heat transfer. The results show that the cooling channels with squared and triangular full-ribs present better cooling effects inside the body blade, reducing the temperature until 10°C at some point in the blade. However, these configurations produce a pressure drop from 3 to 4 times higher than cooling channels without ribs. The half ribs produce lesser temperature decrement, having smaller pressure drop. On other hand, the aspect ratio (P/e) has only effects on the pressure drop.

Optimization of a U-Bend for Minimal Pressure Loss in Internal Cooling Channels: Part I—Numerical Method

2011 ◽  
Author(s):  
Tom Verstraete ◽  
Filippo Coletti ◽  
Je´re´my Bulle ◽  
Timothe´e Vanderwielen ◽  
Tony Arts
Keyword(s):  
Numerical Method ◽  
Pressure Loss ◽  
Total Pressure ◽  
Cooling System ◽  
Differential Evolution Algorithm ◽  
Flow Region ◽  
Total Pressure Loss ◽  
Navier Stokes ◽  
Internal Cooling ◽  
Cooling Channels

This two-parts paper addresses the design of a U-bend for serpentine internal cooling channels optimized for minimal pressure loss. The total pressure loss for the flow in a U-bend is a critical design parameter as it augments the pressure required at the inlet of the cooling system, resulting in a lower global efficiency. In this first part of the paper the design methodology of the cooling channel is presented. The minimization of the total pressure loss is achieved by means of a numerical optimization method that uses a metamodel assisted differential evolution algorithm in combination with an incompressible Navier-Stokes solver. The profiles of the internal and external side of the bend are parameterized using piece-wise Bezier curves. This allows for a wide variety of shapes, respecting the manufacturability constraints of the design. The pressure loss is computed by the Navier-Stokes solver, which is based on a two-equation turbulence model and is available from the open source software OpenFOAM. The numerical method predicts an improvement of 36% in total pressure drop with respect to a circular U-bend, mainly due to the reduction of the separated flow region along the internal side of the bend. The resulting design is subjected to experimental validation, presented in Part II of the paper.

Application of Conjugate Heat Transfer for Cooling Optimization of a Turbine Airfoil

2009 ◽  
Author(s):  
Grzegorz Nowak ◽  
Włodzimierz Wro´blewski
Keyword(s):  
Heat Transfer ◽  
Conjugate Heat Transfer ◽  
Thermal Field ◽  
Cooling System ◽  
Solid Material ◽  
System Optimization ◽  
Point Of View ◽  
Internal Cooling ◽  
Cooling Channels ◽  
Cooling Air

This paper discusses the problem of airfoil cooling system optimization connected with Conjugate Heat Transfer (CHT) analysis for reliable thermal field prediction within a cooled component. Since the full CHT solution, which involves the main flow, blade material and the coolant flow domains is computationally expensive from the point of view of optimization process, it was decided to reduce the problem by fixing the boundary conditions at the blade surface and solving the task for the interior only (both solid material and coolant). Such assumption, on one hand, makes the problem computationally feasible, and on the other, provides more reliable thermal field prediction than it used to be with the empirical relationships. The analysis involves the optimization of location and size of internal cooling passages within an airfoil. Initially, cooling is provided with circular passages and heat is transported by convection. The task is approached in 3D configuration. Each passage is fed with cooling air of constant parameters at the inlet. In the present study the airfoil profile is taken as aerodynamically optimal. The optimization is done with an evolutionary algorithm within a 30 dimensional design space, composed of space coordinates and radii of cooling channels. The search is realized with a weighted single objective function, which consisted of three objectives formulated on the basis of the airfoil’s thermal field and coolant mass flow.

Vibratory Finishing of Laser Powder Bed Fused Stainless Steel 316 Internal Cooling Channels

2021 ◽  
pp. 13-16
Author(s):  
Boon Loong Toh ◽  
Sharan Kumar Gopasetty ◽  
Arun Prasanth Nagalingam ◽  
Joselito Yam II Alcaraz ◽  
Zhang Jing ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Internal Cooling ◽  
Vibratory Finishing ◽  
Powder Bed ◽  
Cooling Channels ◽  
Stainless Steel 316

Optimization of a U-Bend for Minimal Pressure Loss in Internal Cooling Channels—Part I: Numerical Method

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Tom Verstraete ◽  
Filippo Coletti ◽  
Jérémy Bulle ◽  
Timothée Vanderwielen ◽  
Tony Arts
Keyword(s):  
Numerical Method ◽  
Pressure Loss ◽  
Total Pressure ◽  
Cooling System ◽  
Differential Evolution Algorithm ◽  
Flow Region ◽  
Total Pressure Loss ◽  
Navier Stokes ◽  
Internal Cooling ◽  
Cooling Channels

This two-part paper addresses the design of a U-bend for serpentine internal cooling channels optimized for minimal pressure loss. The total pressure loss for the flow in a U-bend is a critical design parameter, as it augments the pressure required at the inlet of the cooling system, resulting in a lower global efficiency. In this first part of the paper, the design methodology of the cooling channel is presented. The minimization of the total pressure loss is achieved by means of a numerical optimization method that uses a metamodel-assisted differential evolution algorithm in combination with an incompressible Navier–Stokes solver. The profiles of the internal and external side of the bend are parameterized using piece-wise Bezier curves. This allows for a wide variety of shapes, respecting the manufacturability constraints of the design. The pressure loss is computed by the Navier–Stokes solver, which is based on a two-equation turbulence model and is available from the open source software OpenFOAM. The numerical method predicts an improvement of 36% in total pressure drop with respect to a circular U-bend, mainly due to the reduction of the separated flow region along the internal side of the bend. The resulting design is subjected to experimental validation, presented in Part II of the paper.

scholarly journals Tailoring Surface Roughness Using Additive Manufacturing to Improve Internal Cooling

2020 ◽  
Vol 142 (7) ◽  
Author(s):  
Jacob C. Snyder ◽  
Karen A. Thole
Keyword(s):  
Surface Roughness ◽  
Additive Manufacturing ◽  
Reynolds Numbers ◽  
Internal Cooling ◽  
Laser Powder Bed Fusion ◽  
Cooling Performance ◽  
Powder Bed ◽  
Random Roughness ◽  
Cooling Channels ◽  
Build Time

Abstract Surface roughness present on internal cooling channels produced with additive manufacturing has been previously shown to augment heat transfer and pressure loss to levels similar to traditionally cast turbulators. Given the ability of the surface roughness to improve the cooling performance of small cooling channels, the question arises on whether there is an optimal combination of random roughness features to maximize internal cooling performance. To investigate this question, test coupons with different surface roughness morphologies and magnitudes were manufactured by manipulating the parameters in the laser powder bed fusion additive manufacturing process. The coupons were tested to characterize the friction factor and Nusselt number of the cooling channels over a range of Reynolds numbers. Results showed that certain roughness combinations outperformed others, increasing the internal cooling performance of the channels. Additionally, manipulation of the performance using the process parameters allowed for reductions in build time, which could be useful for controlling component cost.

Optimization of a U-Bend for Minimal Pressure Loss in Internal Cooling Channels: Part II—Experimental Validation

2011 ◽  
Author(s):  
Filippo Coletti ◽  
Tom Verstraete ◽  
Timothe´e Vanderwielen ◽  
Je´re´my Bulle ◽  
Tony Arts
Keyword(s):  
Pressure Loss ◽  
Cooling System ◽  
Optimization Method ◽  
Design Tool ◽  
Optimized Design ◽  
Internal Cooling ◽  
Cooling Channel ◽  
Piv Measurements ◽  
Cooling Channels ◽  
Numerical Predictions

This two-part paper addresses the design of a U-bend for serpentine internal cooling channels optimized for minimal pressure loss. The total pressure loss for the flow in a U-bend is a critical design parameter as it augments the pressure required at the inlet of the cooling system, resulting in a lower global efficiency. In the first part of the paper the design methodology of the cooling channel was presented. In this second part the optimized design is validated. The results obtained with the numerical methodology described in Part I are checked against pressure measurements and Particle Image Velocimetry (PIV) measurements. The experimental campaign is carried out on a magnified model of a two-legged cooling channel that reproduces the geometrical and aerodynamical features of its numerical counterpart. Both the original profile and the optimized profile are tested. The latter proves to outperform the original geometry by about 36%, in good agreement with the numerical predictions. Two-dimensional PIV measurements performed in planes parallel to the plane of the bend highlight merits and limits of the computational model. Despite the well-known limits of the employed eddy viscosity model, the overall trends are captured. The study demonstrates that the proposed optimization method based on an evolutionary algorithm, a Navier-Stokes solver and a meta-model of it is a valid design tool to minimize the pressure loss across a U-bend in internal cooling channels.

scholarly journals A STRUCTURED APPROACH TO REDUCE DESIGN ITERATIONS IN ADDITIVE MANUFACTURING

2021 ◽  
Vol 1 ◽  
pp. 231-240
Author(s):  
Laura Wirths ◽  
Matthias Bleckmann ◽  
Kristin Paetzold
Keyword(s):  
Additive Manufacturing ◽  
Spare Parts ◽  
Design Guidelines ◽  
Final Part ◽  
Layer By Layer ◽  
Powder Bed ◽  
Batch Sizes ◽  
Manufacturing Technologies ◽  
Structured Approach ◽  
Design Freedom

AbstractAdditive Manufacturing technologies are based on a layer-by-layer build-up. This offers the possibility to design complex geometries or to integrate functionalities in the part. Nevertheless, limitations given by the manufacturing process apply to the geometric design freedom. These limitations are often unknown due to a lack of knowledge of the cause-effect relationships of the process. Currently, this leads to many iterations until the final part fulfils its functionality. Particularly for small batch sizes, producing the part at the first attempt is very important. In this study, a structured approach to reduce the design iterations is presented. Therefore, the cause-effect relationships are systematically established and analysed in detail. Based on this knowledge, design guidelines can be derived. These guidelines consider process limitations and help to reduce the iterations for the final part production. In order to illustrate the approach, the spare parts production via laser powder bed fusion is used as an example.

scholarly journals Optimization Design of Lattice Structures in Internal Cooling Channel with Variable Aspect Ratio of Gas Turbine Blade

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3954
Author(s):  
Liang Xu ◽  
Qicheng Ruan ◽  
Qingyun Shen ◽  
Lei Xi ◽  
Jianmin Gao ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Optimization Model ◽  
Lattice Structure ◽  
Turbine Blades ◽  
Internal Cooling ◽  
Cooling Channel ◽  
Cooling Channels ◽  
Mechanical Performances ◽  
Type Lattice

Traditional cooling structures in gas turbines greatly improve the high temperature resistance of turbine blades; however, few cooling structures concern both heat transfer and mechanical performances. A lattice structure (LS) can solve this issue because of its advantages of being lightweight and having high porosity and strength. Although the topology of LS is complex, it can be manufactured with metal 3D printing technology in the future. In this study, an integral optimization model concerning both heat transfer and mechanical performances was presented to design the LS cooling channel with a variable aspect ratio in gas turbine blades. Firstly, some internal cooling channels with the thin walls were built up and a simple raw of five LS cores was taken as an insert or a turbulator in these cooling channels. Secondly, relations between geometric variables (height (H), diameter (D) and inclination angle(ω)) and objectives/functions of this research, including the first-order natural frequency (freq1), equivalent elastic modulus (E), relative density (ρ¯) and Nusselt number (Nu), were established for a pyramid-type lattice structure (PLS) and Kagome-type lattice structure (KLS). Finally, the ISIGHT platform was introduced to construct the frame of the integral optimization model. Two selected optimization problems (Op-I and Op-II) were solved based on the third-order response model with an accuracy of more than 0.97, and optimization results were analyzed. The results showed that the change of Nu and freq1 had the highest overall sensitivity Op-I and Op-II, respectively, and the change of D and H had the highest single sensitivity for Nu and freq1, respectively. Compared to the initial LS, the LS of Op-I increased Nu and E by 24.1% and 29.8%, respectively, and decreased ρ¯ by 71%; the LS of Op-II increased Nu and E by 30.8% and 45.2%, respectively, and slightly increased ρ¯; the LS of both Op-I and Op-II decreased freq1 by 27.9% and 19.3%, respectively. These results suggested that the heat transfer, load bearing and lightweight performances of the LS were greatly improved by the optimization model (except for the lightweight performance for the optimal LS of Op-II, which became slightly worse), while it failed to improve vibration performance of the optimal LS.

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