Razieh Keshavarzi, Mehdi Jahangiri^*

Energy Engineering, Vol.121, No.6, pp. 1381-1401, 2024, DOI:10.32604/ee.2024.050029

Abstract Nowadays, the use of renewable energies, especially wind, solar, and biomass, is essential as an effective solution to address global environmental and economic challenges. Therefore, the current study examines the energy-economic-environmental analysis of off-grid electricity generation systems using solar panels, wind turbines, and biomass generators in various weather conditions in Iran. Simulations over 25 years were conducted using HOMER v2.81 software, aiming to determine the potential of each region and find the lowest cost of electricity production per kWh. In the end, to identify the most suitable location, the Technique for Order Preference by Similarity… More > Graphic Abstract

Ghobad Shafiei Sabet^1,*, Ali Sari¹, Ahmad Fakhari^2,*, Nasrin Afsarimanesh³, Dominic Organ⁴, Seyed Mehran Hoseini¹

Frontiers in Heat and Mass Transfer, Vol.22, No.2, pp. 491-509, 2024, DOI:10.32604/fhmt.2024.048290

Abstract This study conducts both numerical and empirical assessments of thermal transfer and fluid flow characteristics in a Solar Air Collector (SAC) using a Delta Wing Vortex Generator (DWVG), and the effects of different height ratios (R = 0.6, 0.8, 1, 1.2 and 1.4) in delta wing vortex generators, which were not considered in the earlier studies, are investigated. Energy and exergy analyses are performed to gain maximum efficiency. The Reynolds number based on the outlet velocity and hydraulic diameter falls between 4400 and 22000, corresponding to the volume flow rate of 5.21–26.07 m/h. It is More >

Junhui Li¹, Xuanzhong Luo^1,2, Changxing Ge³, Cuiping Li^1,*, Changrong Wang⁴

Energy Engineering, Vol.121, No.4, pp. 869-893, 2024, DOI:10.32604/ee.2024.029722

Abstract Peak load and wind energy emission pressure rise more as wind energy penetration keeps growing, which affects the stabilization of the PS (power system). This paper suggests integrated optimal dispatching of thermal power generators and BESS (battery energy storage system) taking wind energy emission grading punishment and deep peak clipping into consideration. Firstly, in order to minimize wind abandonment, a hierarchical wind abandonment penalty strategy based on fuzzy control is designed and introduced, and the optimal grid-connected power of wind energy is determined as a result of minimizing the peak cutting cost of the system.… More > Graphic Abstract

Pankaj Saha^a, Gautam Biswas^a,b,*

Frontiers in Heat and Mass Transfer, Vol.2, No.3, pp. 1-5, 2011, DOI:10.5098/hmt.v2.3.3008

Abstract Detailed flow structure in turbulent flows through a rectangular channel containing built-in winglet type vortex generators have been analyzed by means of solutions of the full Navier-Stokes equations using a Large-Eddy Simulation (LES) technique. The Reynolds number of investigation is 6000. The geometry of interest consists of a rectangular channel with a built-in winglet pair on the bottom wall with common-flow-down arrangement. The winglet pair induces streamwise longitudinal vortices behind it. The vortices swirl the flow around the axis parallel to the mainstream direction and disrupt the growth of thermal boundary layer entailing enhancement of… More >

Amnart Boonloi^a, Withada Jedasadaratanachai^b,*

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-15, 2014, DOI:10.5098/hmt.5.19

Abstract 3D numerical investigations for heat transfer characteristics and flow configurations in a fin–and-oval-tube heat exchanger with V-tip pointing downstream delta winglet pairs (DDWP) are examined. The DDWPs are placed on the fin surface with pointing downstream and the oval tube row number is set at three in a staggered arrangement. The flow attack angles (θ = 15°, 30°, 45° and 60°) and the distance from V-tip to the oval tube center in transverse axis (a = 3.77, 4.77 and 5.77 mm) are investigated for Reynolds number based on hydraulic diameter, Re = 500 – 2500. The numerical results… More >

Amnart Boonloi^*

Frontiers in Heat and Mass Transfer, Vol.5, pp. 1-12, 2014, DOI:10.5098/hmt.5.8

Abstract A mathematical analysis of the heat transfer enhancement, thermal performance and flow configurations in a heat exchanger square duct with diagonal inserted plate vortex generators is presented. The 30o V–shaped baffles are modified and placed on the double sides of the thin plate or frame (with no plate) which inserted diagonally in the square duct. The effects of blockage ratio (b/H, BR), the pitch ratio (p/H, PR), flow direction (V–Downstream and V–Upstream) and configuration of inserting plate are investigated for Reynolds number based on the hydraulic diameter of the square duct, D_h, Re = 100 –… More >

Tian Li^1,2,*, Hao Liang¹, Zerui Xiang², Jiye Zhang¹

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.2, pp. 463-473, 2024, DOI:10.32604/fdmp.2023.043618

Abstract A relatively high aerodynamic drag is an important factor that hinders the further acceleration of high-speed trains. Using the shear stress transport (SST) k-ω turbulence model, the effect of various vortex generator types on the aerodynamic characteristics of an ICE2 (Inter-city Electricity) train has been investigated. The results indicate that the vortex generators with wider triangle, trapezoid, and micro-ramp arranged on the surface of the tail car can significantly change the distribution of surface pressure and affect the vorticity intensity in the wake. This alteration effectively reduces the resistance of the tail car. Meanwhile, the micro-ramp More > Graphic Abstract

Mohammad Yaghoub Abdollahzadeh Jamalabadi, Jinxiang Xi^*

Frontiers in Heat and Mass Transfer, Vol.21, pp. 65-79, 2023, DOI:10.32604/fhmt.2023.042613

Abstract As a means of harvesting solar energy for water treatment, solar-driven vapor generation is becoming more appealing. Due to their entangled fibrous networks and high surface area, fibers can be used as building blocks to generate water vapor. In this paper, using a two-dimensional fiber bundle model, we studied the generation of solar vapor based on the fiber height, distance between fibers, and input sun radiation. The performance of solar absorption system was also evaluated by evaluating thermal and water management. Results showed a constant increase in solar vapor generation with an increasing fiber height… More > Graphic Abstract

Withada Jedsadaratanachai^a, Amnart Boonloi^b,*

Frontiers in Heat and Mass Transfer, Vol.6, pp. 1-19, 2015, DOI:10.5098/hmt.6.13

Abstract Numerical investigations on flow topology, heat transfer behavior and thermal performance evaluation in a circular tube heat exchanger with the punched delta winglet vortex generators (PDWVG) inserted in the middle of the test section are presented. The effects of the flow attack angles that converging to the center of the tube; α = 0°, 5°, 10°, 15°, 20°, 25°, and flow directions; winglet tips pointing downstream and upstream, are investigated for the Reynolds numbers; Re = 100 – 2000. The finite volume method and SIMPLE algorithm are used for the current study. The results are presented… 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 >