Constructal Design of Cooling Channel in Heat Transfer System by Utilizing Optimality of Branch Systems in Nature

2005 ◽  
Vol 129 (3) ◽  
pp. 245-255 ◽  
Author(s):  
Xiaohong Ding ◽  
Koetsu Yamazaki
Keyword(s):  
Heat Transfer ◽  
Minimum Energy ◽  
Three Dimensional ◽  
Generation Process ◽  
Transfer System ◽  
Cooling Channel ◽  
Nutrient Distribution ◽  
Cooling Channels ◽  
Nutrient Density ◽  
Heat Transfer System

There are similarities between the morphology of branch systems in nature and the layout of cooling channel in heat transfer system in engineering. The branch systems in nature always grow in such a way that approximate global optimal performances can be achieved. By utilizing the optimality of branch systems in nature, an innovative layout design methodology of cooling channel in heat transfer system is suggested in this paper. The emergent process of branch systems in nature is reproduced according to their common growth mechanisms. Branches are grown under the control of a so-called nutrient density so as to make it possible for the distribution of branches to be dependent on the nutrient distribution. The growth of branches also satisfies the hydrodynamic conditions and the minimum energy loss principle. If the so-called nutrient density in the generation process of branch systems is referred to as the heat energy in a heat transfer system, the distribution of branches is responsible for the distribution of cooling channels. Having similar optimality of branch systems in nature, the constructed cooling channel can be designed flexibly and effectively in any shape of perfusion volume to be cooled adaptively to very complex thermal boundary conditions. The design problems of both a conductive cooling channel and a convective cooling channel are studied, and the layouts of two-dimensional and three-dimensional cooling channels are illustrated. The cooling performances of the designed heat transfer systems are discussed by the finite element method analysis and are compared with the results designed by other conventional design methods.

scholarly journals Heat Transfer during Steaming of Bread

2014 ◽  
Vol 10 (4) ◽  
pp. 613-623 ◽  
Author(s):  
Victoria K. Ananingsih ◽  
Edda Y. L. Sim ◽  
Xiao Dong Chen ◽  
Weibiao Zhou
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Euler Method ◽  
Heating Process ◽  
Temperature Profiles ◽  
Transfer System ◽  
Physicochemical Changes ◽  
Steamed Bread ◽  
Predicted Values ◽  
Heat Transfer System

Abstract Understanding of heat transfer during steaming is important to optimize the processing of steamed bread and to produce desired qualities in the final product. Physicochemical changes occur during steaming of the dough which might be impacted upon by the heat transfer system. In this study, a mathematical model was developed to describe the heat transfer system in the bread being steaming throughout the heating process. The Forward Euler method was employed for solving the three-dimensional partial differential equation set for heat transfer to produce temperature profiles at a number of individual locations in the steamed bread during its steaming. All the comparisons between the model-predicted values and the experimental results produced root mean square error values ranged from 1.391 to 3.545 and R2 values of all greater than 0.93. Therefore, it is confirmed that the model has a good performance and can be used to predict temperature profiles in the bread during steaming.

Preliminary design of EU DEMO helium-cooled breeding blanket primary heat transfer system

2018 ◽  
Vol 136 ◽  
pp. 1567-1571 ◽  
Author(s):  
I. Moscato ◽  
L. Barucca ◽  
S. Ciattaglia ◽  
P.A. Di Maio ◽  
G. Federici
Keyword(s):  
Heat Transfer ◽  
Preliminary Design ◽  
Transfer System ◽  
Heat Transfer System

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.

Analysis of a Virtual Prototype First-Stage Rotor Blade Using Integrated Computer-Based Design Tools

2006 ◽  
Author(s):  
Michel Arnal ◽  
Christian Precht ◽  
Thomas Sprunk ◽  
Tobias Danninger ◽  
John Stokes
Keyword(s):  
Heat Transfer ◽  
Gas Flow ◽  
Thermal Loading ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Life Assessment ◽  
Element Analysis ◽  
Pressure Losses ◽  
Cooling Channels ◽  
Internally Cooled

The present paper outlines a practical methodology for improved virtual prototyping, using as an example, the recently re-engineered, internally-cooled 1st stage blade of a 40 MW industrial gas turbine. Using the full 3-D CAD model of the blade, a CFD simulation that includes the hot gas flow around the blade, conjugate heat transfer from the fluid to the solid at the blade surface, heat conduction through the solid, and the coolant flow in the plenum is performed. The pressure losses through and heat transfer to the cooling channels inside the airfoil are captured with a 1-D code and the 1-D results are linked to the three-dimensional CFD analysis. The resultant three-dimensional temperature distribution through the blade provides the required thermal loading for the subsequent structural finite element analysis. The results of this analysis include the thermo-mechanical stress distribution, which is the basis for blade life assessment.

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