Next Issue
Volume 11, 01
Previous Issue
Volume 10, 06
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
IJTST
Volume 10
Issue 4
share announcement
International Journal of Thermofluid Science and Technology is published by MDPI from Volume 13 Issue 1 (2026). Previous articles were published by another publisher in Open Access under a CC-BY (or CC-BY-NC-ND) licence, and they are hosted by MDPI on mdpi.com as a courtesy and upon agreement with the previous journal publisher.

Int. J. Thermofluid Sci. Technol., Volume 10, Issue 4 (10 2023) – 5 articles

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
272 KB  
Article
Effect of Viscous Dissipation on the Onset of Jeffery Fluid Porous Convection in the Presence of Throughflow and Electric Field
by Gangadharaiah Y H and Nagarathnamma H
Int. J. Thermofluid Sci. Technol. 2023, 10(4), 100405; https://doi.org/10.36963/IJTST.2023100405 - 4 Dec 2023
Viewed by 61
Abstract
In this paper, A numerical analysis of Jeffrey fluid flow in a porous matrix with a collective impact of through flow, external electric field and viscous dissipation, was conducted to examine the onset of thermal convection. The critical Rayleigh number for stationary mode [...] Read more.
In this paper, A numerical analysis of Jeffrey fluid flow in a porous matrix with a collective impact of through flow, external electric field and viscous dissipation, was conducted to examine the onset of thermal convection. The critical Rayleigh number for stationary mode was determined using Galerkin processes and linear stability assumptions based on the normal mode procedure. The study investigated the effects of several key factors, including throughflow, viscous dissipation, electric field, and Jeffrey parameters, with their impacts analyzed through graphs. It was observed that higher values of the Jeffrey parameter, viscous dissipation term, and throughflow parameters tend to stabilize the system, while an increased electric field parameter accelerates the onset of convection. Full article
►▼ Show Figures

Figure 1

766 KB  
Article
Performance analysis of ejector refrigeration cycle with zeotropic mixtures
by Mohammed Mehemmai, Hichem Grine, Hakim Madani and Cherif Bougriou
Int. J. Thermofluid Sci. Technol. 2023, 10(4), 100404; https://doi.org/10.36963/IJTST.2023100404 - 2 Dec 2023
Cited by 1 | Viewed by 105
Abstract
In this article, we present an energetic and thermodynamic study of a refrigeration cycle with ejector (RCE), through a zeotropic binary fluid. In this context, four binary mixtures based on R1234yf were chosen given their minimum GWP values. The objective is to determine [...] Read more.
In this article, we present an energetic and thermodynamic study of a refrigeration cycle with ejector (RCE), through a zeotropic binary fluid. In this context, four binary mixtures based on R1234yf were chosen given their minimum GWP values. The objective is to determine their values of coefficients of performance (COP) by changing each time the composition of the fluid mixture studied. The results obtained for the COP and the entrainment ratio were determined for different temperatures condensation (Tc), temperatures evaporation (Te) and different mass fractions (Mf). The study showed that the coefficient of performance (COP) values decreases with increasing condensation temperature (Tc), as the evaporation temperature (Te) increases the COP increases. The maximum coefficient of performance (COP) values are: 10.02 for the R1234yf +R152a system, 9.83 for the R1234yf + R134a system, 9.67 for the R1234yf + R32 system, 9.59 for the R1234yf + R125 system of 9.59 whose mass percentage of R1234yf is: 0.75, 0.45, 0.05 and 0.05 respectively. A particle study on the effect of glide temperature (Tg) was inserted for the selected binary systems either. The results showed that the temperature glide is inversely related to the COP at the evaporator and condenser levels and in all four mixtures. So, a decrease in temperature glide (Tg) leads to better performance. Full article
►▼ Show Figures

Figure 1

1836 KB  
Article
Evaluation of conventional fluid mechanic theory in small channels with singularity
by Sid Ali Si Salah, Abdelwahid Azzi and El Ghalia Filali
Int. J. Thermofluid Sci. Technol. 2023, 10(4), 100403; https://doi.org/10.36963/IJTST.2023100403 - 30 Nov 2023
Viewed by 49
Abstract
This study employs numerical simulations using the combined control volume finite element method (CVFEM) to analyze 2D steady, incompressible laminar flow over a microscale backward facing step within a horizontal duct. The investigation focuses on the impact of Reynolds number (Red) [...] Read more.
This study employs numerical simulations using the combined control volume finite element method (CVFEM) to analyze 2D steady, incompressible laminar flow over a microscale backward facing step within a horizontal duct. The investigation focuses on the impact of Reynolds number (Red) and expansion ratio (ER) on flow behavior, aiming to assess the applicability of conventional hydrodynamics at the microscale. The findings reveal that, for an expansion ratio of 2, the flow structure transforms progressively with varying Reynolds numbers in both laminar and transitional flow regimes. Notably, three recirculation zones develop downstream of the step, two along the lower wall and one along the upper wall. The primary recirculation zone's size expands as Reynolds number increases, contracting when a third recirculation zone emerges on the lower wall (Red ≥ 950). The study successfully matches its numerical predictions with experimental observations from larger-scale backward-facing steps for Reynolds numbers up to 500, maintaining two-dimensional flow characteristics. Furthermore, the computed velocity profiles align closely with experimental outcomes, except for Red = 1000, where the experimental flow shifts to three-dimensionality. The study also examines loss coefficients (Ke), revealing substantially higher values than conventional macro systems for Reynolds numbers above 200. However, for lower Reynolds numbers, the loss coefficient varies accordingly. For expansion ratios of 1.5, 2.0, and 2.5, fluid flow properties such as pressure, Poiseuille number, and friction factors exhibit good agreement with macroscale theory for fully developed laminar flow (Red ≤ 500). Full article
►▼ Show Figures

Figure 1

1962 KB  
Article
Natural convection of power-law fluid in a horizontal annulus between outer cylinder and inner flat tube
by Benhizia Oussama and Bouzit Mohamed
Int. J. Thermofluid Sci. Technol. 2023, 10(4), 100402; https://doi.org/10.36963/IJTST.2023100402 - 22 Nov 2023
Viewed by 43
Abstract
Natural convection in two-dimensional space created by putting horizontal flat tube concentrically in cooled horizontal cylinder is studied numerically. The model solved using the ANSYS CFX package. The numerical simulations covered a range of power-law index 0.6≤n≤1.4, Prandtl number 10≤Pr≤103 and Rayleigh [...] Read more.
Natural convection in two-dimensional space created by putting horizontal flat tube concentrically in cooled horizontal cylinder is studied numerically. The model solved using the ANSYS CFX package. The numerical simulations covered a range of power-law index 0.6≤n≤1.4, Prandtl number 10≤Pr≤103 and Rayleigh number 103≤Ra≤105. The effects of the previous parameters on the flow pattern, the average Nusselt number and the dimensionless temperature and velocity profiles have been investigated. The results showed that the average Nusselt number increases with increasing Rayleigh number and decreases with increasing the power-law index. The best case among the range of parameters considered here is the heat transfer rate of pseudo-plastic fluids (n=0.6), then the Newtonian fluids (n=1) and finally, the dilatant fluids (n=1.4). It is shown that the sharpness cooling effect of pseudo-plastic fluids and the sharpness insulating effect of dilatant fluids hugely affected by the increasing of Rayleigh number. The Prandtl number has almost no effects on the heat transfer rate in the range considered here. The results for the average Nusselt number and the dimensionless temperature have been compared versus some previous works and showed good agreement. Full article
►▼ Show Figures

Figure 1

1958 KB  
Article
Thermo-fluidic characteristics of an aerodynamic swirl nozzle with low-concentration nanofluids
by MD Tanvir Khan, Sudipta Debnath and Zahir U. Ahmed
Int. J. Thermofluid Sci. Technol. 2023, 10(4), 100401; https://doi.org/10.36963/IJTST.2023100401 - 9 Oct 2023
Viewed by 84
Abstract
Anticipating the swirl turbulent flow and heat transfer phenomena within a nozzle is tremendously challenging due to the complexities of measurement diagnostics. The amalgamation of nanoparticles with fluids often exacerbates this perplexity for the resurgence of effective fluid properties that ambiguously affect thermo-fluidic [...] Read more.
Anticipating the swirl turbulent flow and heat transfer phenomena within a nozzle is tremendously challenging due to the complexities of measurement diagnostics. The amalgamation of nanoparticles with fluids often exacerbates this perplexity for the resurgence of effective fluid properties that ambiguously affect thermo-fluidic behaviors. This study numerically focuses on the low concentration (1%) nanoparticles to investigate the effect of swirl as well as nanofluids on the flow and thermal characteristics of incompressible turbulent liquid jets. Both the aqueous and nonaqueous nanofluids are taken into consideration in a variety of flow conditions. The aqueous nanofluid resembles the properties of water, while the thermofluidic behavior of the non-aqueous nanofluids differs significantly. The Reynolds number enhances the average Nusselt number as well as the pressure drop inside the nozzle, and the non-aqueous nanofluids exhibit a relatively higher average Nusselt number and pressure drop. The average Nusselt number increases up to 322% for Dowtherm + Al2O3, and 320% for Syltherm800 + Al2O3 compared to H2O. Aqueous nanofluid indicates a higher thermal performance factor than non-aqueous nanofluids. The skin friction coefficient decreases with the Reynolds number since the effective viscosity reduces. (CH2OH)2 + Al2O3 predicts the maximum heat transfer rate albeit with a penalty of high-pressure drop. Correlations are developed for the average Nusselt number and thermal performance factor to relate several control parameters. Full article
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying articles 1-5
Previous Issue
Next Issue
Back to TopTop