scholarly journals Enhanced Thermoelectric Cooling through Introduction of Material Anisotropy in Transverse Thermoelectric Composites

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2049
Author(s):  
Bosen Qian ◽  
Fei Ren ◽  
Yao Zhao ◽  
Fan Wu ◽  
Tiantian Wang
Keyword(s):  
Mathematical Model ◽  
Single Crystal ◽  
Material Properties ◽  
Cooling Capacity ◽  
Thermoelectric Performance ◽  
Cooling Power ◽  
Material Anisotropy ◽  
Element Analysis ◽  
The Mathematical Model ◽  
Component Phase

Transverse thermoelectric materials can achieve appreciable cooling power with minimal space requirement. Among all types of material candidates for transverse thermoelectric applications, composite materials have the best cooling performance. In this study, anisotropic material properties were applied to the component phase of transverse thermoelectric composites. A mathematical model was established for predicting the performance of fibrous transverse thermoelectric composites with anisotropic components. The mathematical model was then validated by finite element analysis. The thermoelectric performance of three types of composites are presented, each with the same set of component materials. For each type of component, both anisotropic single-crystal and isotropic polycrystal material properties were applied. The results showed that the cooling capacity of the system was improved by introducing material anisotropy in the component phase of composite. The results also indicated that the orientation of the anisotropic component’s property axis, the anisotropic characteristic of a material, will significantly influence the thermoelectric performance of the composite. For a composite material consisting of Copper fiber and Bi2Te3 matrix, the maximum cooling capacity can vary as much as 50% at 300 K depending on the property axis alignment of Bi2Te3 in the composite. The composite with Copper and anisotropic SnSe single crystal had a 51% improvement in the maximum cooling capacity compared to the composite made of Copper and isotropic SnSe polycrystals.

scholarly journals Performance Evaluation of a Gravity-Assisted Heat Pipe-Based Indirect Evaporative Cooler

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 200 ◽  
Author(s):  
Krzysztof Rajski ◽  
Jan Danielewicz ◽  
Ewa Brychcy
Keyword(s):  
Mathematical Model ◽  
Heat Pipe ◽  
Cooling Capacity ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Mass Transfer Processes ◽  
Air Cooler ◽  
Evaporative Cooler ◽  
The Mathematical Model ◽  
Further Development

In the present work, the effects of different operating parameters on the performance of a gravity-assisted heat pipe-based indirect evaporative cooler (GAHP-based IEC) were investigated. The aim of the theoretical study is to evaluate accurately the cooling performance indicators, such as the coefficient of performance (COP), wet bulb effectiveness, and cooling capacity. To predict the effectiveness of the air cooler under a variety of conditions, the comprehensive calculation method was adopted. A mathematical model was developed to simulate numerically the heat and mass transfer processes. The mathematical model was validated adequately using experimental data from the literature. Based on the conducted numerical simulations, the most favorable ranges of operating conditions for the GAHP-based IEC were established. Moreover, the conducted studies could contribute to the further development of novel evaporative cooling systems employing gravity-assisted heat pipes as efficient equipment for transferring heat.

scholarly journals MODELLING A COMPLIANT-BASED PRECISE POSITIONING STAGE / AUKŠTO TIKSLUMO POZICIONAVIMO SISTEMOS MODELIAVIMAS TAIKANT BESIDEFORMUOJANČIUS MECHANIZMUS

2013 ◽  
Vol 6 (4) ◽  
pp. 523-527 ◽  
Author(s):  
Giedrius Augustinavičius ◽  
Audrius Čereška
Keyword(s):  
Mathematical Model ◽  
Finite Element Analysis ◽  
Positioning System ◽  
Element Analysis ◽  
Precise Positioning ◽  
Positioning Systems ◽  
Positioning Stage ◽  
Amplification Mechanism ◽  
Analytical Approaches ◽  
The Mathematical Model

The paper presents modelling precise dual axis flexure-based precision positioning systems for micro-positioning applications. The positioning system is featured with monolithic architecture, flexure-based joints and piezo stacks. Its workspace has been evaluated via analytical approaches. Amplification mechanism is optimally designed. The mathematical model of the positioning system has been derived and verified by resorting to finite element analysis (FEA). The established analytical and (FEA) models are helpful for optimizing reliable architecture and improving the performance of the positioning system. Santrauka Straipsnyje pristatomas dviejų ašių didelio tikslumo pozicionavimo sistemos su paketiniais pjezovykdikliais modeliavimas, taikant besideformuojančius vientiso kūno mechanizmus. Pozicionavimo sistemą sudaro besideformuojančio vientiso kūno mechanizmas ir paketiniai pjezovykdikliai. Besideformuojantis vientiso kūno mechanizmas norimam poslinkiui pasiekti buvo optimizuotas Solidworks Simulation programiniu paketu. Platformų poslinkiams apskaičiuoti sudarytas matematinis modelis, kurio patikimumas patikrintas baigtinių elementų metodu. Sudaryto matematinio modelio ir rezultatų, gautų baigtinių elementų metodu, skirtumai yra mažesni nei 5 %, todėl pasiūlyta modeliavimo metodika gali būti taikoma kuriant pozicionavimo sistemas su besideformuojančiais elementais.

scholarly journals Developing an Analytical Model and Computing Tool for Optimizing Lapping Operations of Flat Objects Made of Alloyed Steels

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1343 ◽  
Author(s):  
Tudor Deaconescu ◽  
Andrea Deaconescu
Keyword(s):  
Mathematical Model ◽  
Surface Roughness ◽  
Material Properties ◽  
Depth Of Cut ◽  
Operation Optimization ◽  
Abrasive Grains ◽  
Finishing Process ◽  
Real World Applications ◽  
The Mathematical Model

Lapping is a finishing process where loose abrasive grains contained in a slurry are pressed against a workpiece to reduce its surface roughness. To perform a lapping operation, the user needs to set the values of the respective lapping conditions (e.g., pressure, depth of cut, the rotational speed of the pressing lap plate, and alike) based on some material properties of the workpiece, abrasive grains, and slurry, as well as on the desired surface roughness. Therefore, a mathematical model is needed that establishes the relationships among the abovementioned parameters. The mathematical model can be used to develop a lapping operation optimization system, as well. To this date, such a model and system are not available mainly because the relationships among lapping conditions, material properties of abrasive grains and slurry, and surface roughness are difficult to establish. This study solves this problem. It presents a mathematical model establishing the required relationships. It also presents a system developed based on the mathematical model. In addition, the efficacy of the system is also shown using a case study. This study thus helps systematize lapping operations in regard to real-world applications.

Structure of Parametric Designing Simulation Platform of Automotive Air Conditioning Condenser

2012 ◽  
Vol 220-223 ◽  
pp. 689-692
Author(s):  
Yi Hua Ni ◽  
Hai Guo ◽  
Jian Wu ◽  
Jiang Xin Yang
Keyword(s):  
Mathematical Model ◽  
Air Conditioning ◽  
Heat Transfer Performance ◽  
Programming System ◽  
Transfer Performance ◽  
Operating Characteristics ◽  
Element Analysis ◽  
Automotive Air Conditioning ◽  
Element Simulation ◽  
The Mathematical Model

The physical and mathematical model of parallel flow automotive air condition condenser was built based on the analysis of its structure and operating characteristics; then the mathematical model was verified and optimized through finite element analysis and running experiments. The VB programming system was used to do Solidworks pro-development and condenser parameterization design module was built. Finally a condenser design and study platform facing to the heat transfer performance and structure with infinite element simulation and numerical simulation was realized.

scholarly journals Finite element analysis of a single conductor with a Stockbridge damper under Aeolian vibration

2021 ◽  
Author(s):  
Oumar Barry
Keyword(s):  
Mathematical Model ◽  
Finite Element ◽  
Fatigue Failure ◽  
Excitation Frequency ◽  
Element Model ◽  
Element Analysis ◽  
Vibrational Response ◽  
Aeolian Vibration ◽  
The Mathematical Model ◽  
Stockbridge Damper

A finite element model is developed to predict the vibrational response of a single conductor with a Stockbride damper. The mathematical model accounts for the two-way coupling between the conductor and the damper. A two-part numerical analysis using MATLAB is presented to simulate the response of the system. The first part deals with the vibration of the conductor without a damper. The results indicate that longer span conductors without dampers are susceptible to fatigue failure. In the second part, a damper is attached to the conductor and the effects of the excitation frequency, the damper mass, and the damper location are investigated. This investigation shows that the presence of a properly positioned damper on the conductor significantly reduces fatigue failure.

scholarly journals Modelling and thermodynamic analysis of ejector flow for application at design and off design operating conditions in an ejector air conditioner

2021 ◽  
Vol 12 (3) ◽  
pp. 3455-3467
Author(s):  
Anoop Kumar. M Et.al
Keyword(s):  
Mathematical Model ◽  
Heat Input ◽  
Flow Analysis ◽  
Cooling Capacity ◽  
Two Phase ◽  
Entrainment Ratio ◽  
Air Conditioning System ◽  
The Mathematical Model ◽  
Minimum Quality

Ejector flow in an ejector air conditioning system using R245fa is analysed for entrainment ratio and potential refrigeration effect, at varying temperature and heat input conditions in  the generator ranging from 60C to 100C and 2kW to 5kW respectively. The effect of varying generator temperature in cooling capacity of the system when the vapour ejectoris operating at design evaporator and condenser temperatures of 10C and 35C respectively is investigated. The mathematical model of the vapour ejector with optimum area ratio is developed and validated. A critical entrainment ratio of 0.385 is obtained corresponding to generator temperature of 100C. When the generator temperature is varied from 60C to 100C, the cooling capacity range from 0.3kW at generator heat input of 2 kW to 1.78 kW at 5 kW heat input. Further, the operation of the system is analysed for off design operating condition corresponding to reduced heat input rate in the generator. In that case the state of primary refrigerant flow in ejector inlet will be two phase and a mathematical model for two-phase ejector flow is developed and validated. Ejector flow analysis revealed the minimum quality of flow at ejector inlet to maintain adequate backpressure for condensation to occur range from 0.72 at 60C to 0.22 at 100C. The corresponding refrigeration refrigeration effect produced is less than the respective designed operation value byits  12.2% to 8%. Further, analysis of the system shows that at least 7 kW heat input at 100C is required to produce 1 ton of cooling effect. Ejector flow in an ejector air conditioning system using R245fa is analysed for entrainment ratio and potential refrigeration effect, at varying temperature and heat input conditions in  the generator ranging from 60C to 100C and 2kW to 5kW respectively. The effect of varying generator temperature in cooling capacity of the system when the vapour ejectoris operating at design evaporator and condenser temperatures of 10C and 35C respectively is investigated. The mathematical model of the vapour ejector with optimum area ratio is developed and validated. A critical entrainment ratio of 0.385 is obtained corresponding to generator temperature of 100C. When the generator temperature is varied from 60C to 100C, the cooling capacity range from 0.3kW at generator heat input of 2 kW to 1.78 kW at 5 kW heat input. Further, the operation of the system is analysed for off design operating condition corresponding to reduced heat input rate in the generator. In that case the state of primary refrigerant flow in ejector inlet will be two phase and a mathematical model for two-phase ejector flow is developed and validated. Ejector flow analysis revealed the minimum quality of flow at ejector inlet to maintain adequate backpressure for condensation to occur range from 0.72 at 60C to 0.22 at 100C. The corresponding refrigeration refrigeration effect produced is less than the respective designed operation value byits  12.2% to 8%. Further, analysis of the system shows that at least 7 kW heat input at 100C is required to produce 1 ton of cooling effect.

The Finite Element Analysis and Structure Optimizing of the 42MN Flatting Mill’s Higher Beam

2010 ◽  
Vol 145 ◽  
pp. 317-320
Author(s):  
Chun Ming Zhang ◽  
Run Yuan Hao
Keyword(s):  
Mathematical Model ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Design ◽  
Structural Parameters ◽  
Element Model ◽  
Optimum Structure ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
The Mathematical Model

This text is on the basis of the investigation of the 42MN flatting mill’s higher beam, establishing the flatting mill’s higher beam’s finite element model and the mathematical model which has optimum structure. According to the results of their structure finite element analysis, weaved the relevant procedures and optimized them, obtained ideal structural parameters, this text provide better ideas and ways for the structural design of the flatting mill’s higher beam.

A Study on the Nanoindentation Behaviour of Single Crystal Silicon Using Hybrid MD-FE Method

2008 ◽  
Vol 32 ◽  
pp. 259-262 ◽  
Author(s):  
Akbar Afaghi Khatibi ◽  
Bohayra Mortazavi
Keyword(s):  
Molecular Dynamics ◽  
Finite Element ◽  
Single Crystal ◽  
Material Properties ◽  
Single Crystal Silicon ◽  
Dynamics Simulation ◽  
Fe Method ◽  
Crystal Silicon ◽  
Element Analysis ◽  
Nano Scale

Developing new techniques for the prediction of materials behaviors in nano-scales has been an attractive and challenging area for many researches. Molecular Dynamics (MD) is the popular method that is usually used to simulate the behavior of nano-scale material. Considering high computational costs of MD, however, has made this technique inapplicable as well as inflexible in various situations. To overcome these difficulties, alternative procedures are thought. Considering its capabilities, Finite Element Analysis (FEA) seems to be the most appropriate substitute for MD simulations in most cases. But since the material properties in nano, micro, and macro scales are different, therefore to use FEA methods in nano-scale modeling one must use material properties appropriate to that scale. To this end, a previously developed Hybrid Molecular Dynamics-Finite Element (HMDFE) approach was used to investigate the nanoindentation behavior of single crystal silicon with Berkovich indenter. In this study, a FEA model was developed based on the material properties extracted from molecular dynamics simulation of uniaxial tension test on single crystal Silicon. Eventually, by comparison of FEA results with experimental data, the validity of this new technique for the prediction of nanoindentation behavior of Silicon was concluded.

Optimal Method of Selection of Water Lubricated Rubber Bearing Materials

2016 ◽  
Vol 705 ◽  
pp. 3-7 ◽  
Author(s):  
Zhao Chen ◽  
Yu Guang Li ◽  
She Sheng Zhang
Keyword(s):  
Mathematical Model ◽  
Material Properties ◽  
Operational Research ◽  
Optimal Selection ◽  
Optimal Method ◽  
Maximum Value ◽  
Rubber Bearing ◽  
Bearing Materials ◽  
The Mathematical Model ◽  
Selection Of

Excellent material can improve the function of water lubricated stern bearing. According to the material properties and the theory of operational research, the mathematical model of the optimal selection material of water lubricated rubber bearing is established. The condition of selecting materials is discussed. The expression of the maximum value is obtained by using software. The influence of material properties on the objective function is discussed.

A Hydraulic Analogue Model and Analysis of a Micropump Considering the Diaphragm Stiffness

2008 ◽  
Vol 392-394 ◽  
pp. 116-120
Author(s):  
Dan Jiang ◽  
Song Jing Li ◽  
Gang Bao
Keyword(s):  
Mathematical Model ◽  
Finite Element Analysis ◽  
Dynamic Characteristics ◽  
Simulation Method ◽  
Element Analysis ◽  
Analogue Model ◽  
Frequency Calculation ◽  
Simulation Results ◽  
Natural Frequency Calculation ◽  
The Mathematical Model

In order to predict the dynamic characteristics, the piezoelectric valve-less diffuser micropump is equivalent to the hydraulic model which consists of several hydraulic components. Using finite element analysis (FEA) method, the static analysis and the natural frequency calculation of the diaphragm are carried out. The mathematical model and the simulation method using AMESim are developed. Simulation results show the pressure and flow rate characteristics of the micropump, as well as the diaphragm stiffness influence. The agreement between the simulation results and those published previously indicates that the method combining FEA with the hydraulic analogue model provides a relatively simple and effective tool to study the dynamic characteristics of micropumps.

Sign in / Sign up

Export Citation Format

Share Document