Rachid Maouedj¹, Younes Menni², Mustafa Inc^3,4,*, Yu-Ming Chu^5,6,*, Houari Ameur⁷, Giulio Lorenzini⁸

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.3, pp. 855-889, 2021, DOI:10.32604/cmes.2021.014524 - 19 February 2021

Abstract Re-engineering the channel heat exchangers (CHEs) is the goal of many recent studies, due to their great importance in the scope of energy transport in various industrial and environmental fields. Changing the internal geometry of the CHEs by using extended surfaces, i.e., VGs (vortex generators), is the most common technique to enhance the efficiency of heat exchangers. This work aims to develop a new design of solar collectors to improve the overall energy efficiency. The study presents a new channel design by introducing VGs. The FVM (finite volume method) was adopted as a numerical technique… More >

Mohamed Salmi^1,2, Younes Menni³, Ali J. Chamkha^4,5,*, Houari Ameur⁶, Rachid Maouedj⁷, Ahmed Youcef⁷

CMES-Computer Modeling in Engineering & Sciences, Vol.126, No.1, pp. 147-173, 2021, DOI:10.32604/cmes.2021.012839 - 22 December 2020

Abstract The hydrothermal behavior of air inside a solar channel heat exchanger equipped with various shaped ribs is analyzed numerically. The bottom wall of the exchanger is kept adiabatic, while a constant value of the temperature is set at the upper wall. The duct is equipped with a flat rectangular fin on the upper wall and an upstream V-shaped baffle on the lower wall. Furthermore, five hot wall-attached rib shapes are considered: trapezoidal, square, triangular pointing upstream (type I), triangular pointing downstream (type II), and equilateral-triangular (type III) cross sections. Effects of the flow rates are… More >

Miaohong Su¹, Haiying Dong^1,2,*, Kaiqi Liu¹, Weiwei Zou¹

Energy Engineering, Vol.117, No.6, pp. 439-452, 2020, DOI:10.32604/EE.2020.011805 - 16 October 2020

Abstract A subsynchronous oscillation suppression strategy based on self-adaptive auto disturbance rejection proportional integral controller is proposed for doublyfed induction generator-based wind farm integrated into grid through voltage source converter based multi-terminal direct current. In this strategy, the nonlinear PI controller is constructed by fal function to replace the traditional linear PI controller, and then the tracking differentiator is used to arrange the appropriate transition process in combination with the idea of active disturbance rejection control, and the self-adaptive auto disturbance rejection proportional integral controller is designed. By applying the controller to the inner loop of the… More >

Yong Guan¹, Wanling Hu^{1, 2, *}, Yun Zhang¹, Kewei Song^{2, 3}, Liangbi Wang^{2, 3}

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.1, pp. 237-256, 2020, DOI:10.32604/cmes.2020.09141 - 01 April 2020

Abstract The application of vortex generators in tube-finned heat exchangers is very universal. The vortex generators can generate secondary flow, and as we all know secondary flow can obviously strengthen heat transfer. To use vortex generators much more efficiently in the circle tube-finned heat exchangers, the intensity correlation study between secondary flow and heat transfer is needed. 22 different structures of circle tubefinned heat exchangers were numerically studied, including the plain fin cases and the cases with vortex generators. In addition, the influence of fin spacing, transverse and longitudinal tube pitch, heights and attack angle of More >

Wei Zhang¹, Weifeng Shi², Bing Sun³

Intelligent Automation & Soft Computing, Vol.25, No.3, pp. 423-431, 2019, DOI:10.31209/2018.100000045

Abstract An intelligent optimization algorithm for a marine generator excitation controller is proposed to improve dynamic performance of shipboard power systems. This algorithm combines a belief–desire–intention agent with a quantum-behaved particle swarm optimization (QPSO) algorithm to optimize a marine generator excitation controller. The shipboard zonal power system is simulated under disturbance due to load change or severe fault. The results show that the proposed optimization algorithm can improve marine generator stability compared with conventional excitation controllers under various operating conditions. Moreover, the proposed intelligent algorithm is highly robust because its performance is insensitive to the accuracy More >

Zhaowei Qu^1,*, Bingyu Cao¹, Xiaoru Wang¹, Fu Li², Peirong Xu¹, Luhan Zhang¹

CMC-Computers, Materials & Continua, Vol.59, No.2, pp. 575-589, 2019, DOI:10.32604/cmc.2019.05569

Abstract Images are complex multimedia data which contain rich semantic information. Most of current image description generator algorithms only generate plain description, with the lack of distinction between primary and secondary object, leading to insufficient high-level semantic and accuracy under public evaluation criteria. The major issue is the lack of effective network on high-level semantic sentences generation, which contains detailed description for motion and state of the principal object. To address the issue, this paper proposes the Attention-based Feedback Long Short-Term Memory Network (AFLN). Based on existing codec framework, there are two independent sub tasks in… More >

Ming-Hsiao Lee^1,*, Shou-I Chen², Wen-Hwa Chen³, Ying Mao³

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.2, pp. 363-374, 2019, DOI:10.32604/cmes.2019.06476

Abstract 3D Printing, also called Additive Manufacturing, has become a promising manufacturing method to produce parts in various fields as it can produce parts even with very irregular shapes in a relatively shorter process and time. However, during the printing process, some problems could decrease the accuracy and quality of the printed parts, such as warpage due to thermal strains, deformation due to inadequate supports, etc. The finite element method is most commonly adopted to evaluate engineering problems in advance to reduce possible failures; however, the element meshes, needed for analyses, are always irregularly distributed, especially… More >

Weera Punin^*, Somchai Maneewan, Chantana Punlek

Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-5, 2018, DOI:10.5098/hmt.11.22

Abstract In the present experimental investigation, ethylene glycol cooling in a plate-fin heat sink was attached inside an aluminum cooling block for the cooling unit of a thermoelectric (TE) power generator system. The plate-fin heat sink with two different fin heights was made from aluminum with length, width and base thickness of 300, 200, and 25 mm, respectively. The ethylene glycol was used as a coolant. The effects of fin height, coolant volume flow rate, and hot side surface temperature were considered for the temperature differences between the hot side surface and cold side surface of… More >

A. M. E. Ramírez-Mendoza¹

CMES-Computer Modeling in Engineering & Sciences, Vol.115, No.3, pp. 295-311, 2018, DOI:10.3970/cmes.2018.00239

Abstract A spike response model (SRM) based on the spikes generator circuit (SGC) of adaptive fuzzy spiking neurons (AFSNs) is developed. The SRM is simulated in MatlabTM environment. The proposed model is applied to a configuration of a fuzzy exclusive or (fuzzy XOR) operator, as an illustrative example. A description of the comparison of AFSNs with other similar methods is given. The novel method of the AFSNs is used to determine the value of the weights or parameters of the fuzzy XOR, first with dynamic weights or self-tuning parameters that adapt continuously, then with fixed weights More >

Amnart Boonloi^a, Withada Jedsadaratanachai^b,*

Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-16, 2016, DOI:10.5098/hmt.7.22

Abstract The numerical investigations on flow structure, heat transfer characteristic and thermal performance in a circular tube heat exchanger with various shapes of winglet vortex generators are reported. The rectangular winglet vortex generators (RWVG), delta winglet vortex generators (DWVG) and curve winglet vortex generators (CWVG) are inserted in the middle of the test tube on both downstream and upstream arrangements. The effects of blockage ratios; BR = 0.1 – 0.3, with single pitch ratio (PR = 1) and flow attack angle (α = 30o) on thermal performance are studied for the Reynolds numbers; Re = 100 – 2000. The… More >