Engineeringness’ Post

I'm delighted to share my latest research paper, "General wetting energy boundary condition in a fully explicit non-ideal fluids solver." This paper delves into the intriguing realm of fluid dynamics and computational modeling, where we introduce a thermodynamically consistent wetting energy boundary condition for an explicit van der Waals (vdW) solver. Our study explores the difference between several classical approaches to modeling non-ideal fluids wetting problems and enhancing the accuracy of wetting boundary conditions. If you have a passion for the intricacies of fluid dynamics and thermodynamics, I encourage you to read and engage with our research on LinkedIn. Let's foster a vibrant discussion on the future of computational fluid dynamics and its wide-ranging applications. #FluidDynamics #Thermodynamics #ResearchPublication https://lnkd.in/ewCtR936

We (Nithin Mohan Narayan, Udo Fritsching) are extremely delighted to announce our new publication titled "Investigation of the hydrodynamic and thermodynamic behavior of the liquid jet quenching process" which has been published recently in Heat and Mass Transfer Journal (Springer), #openaccess. Doi: https://lnkd.in/ewWBHMev This work focuses on the global numerical modeling (3D) of liquid jet quenching considering all the boiling phases such as film, transient, nucleate as well as the convective cooling phase. To analyse the hydrodynamic and thermodynamic perspectives, experiments with infrared and high speed imaging are performed at our prestigious Leibniz-Institut für Werkstofforientierte Technologien - IWT and University of Bremen laboratories, providing detailed insights into this complex multiphase process. The simulations are performed with the help of north german super computing facility (HLRN/NHR). The technical parameters such as heat flux, HTC, cooling curve, wetting front etc. are investigated providing suitable correlations for technical application and optimization of processes. We have also been able to define new terms such as precooling width for analyzing the process and in a novel approach, evaluated the Heat transfer coefficient (HTC) based on the average liquid film temperature above the hot surface and the influence of dynamic water temperature on heat transfer during the liquid jet quenching. Thank you. Open access link: https://lnkd.in/eSMMPy_e #cfd #heattransfer #numerical #experiment

Assessment of Immersed Boundary Methods for #Hypersonic Flows with Gas-Surface Interactions Ata Onur Başkaya, Michele Capriati, Alessandro Turchi, Thierry Magin, Stefan Hickel Abstract. Immersed boundary (IB) methods with adaptive mesh refinement (AMR) techniques are assessed for atmospheric entry applications, including effects of chemical nonequilibrium (#CNE) and gas-surface interactions (#GSI). The performance of a conservative cut-cell and two non-conservative ghost-cell IB methods is assessed in comparison with analytical solutions, data from literature, and results obtained with a reference solver that operates on body-fitted grids. All solvers use the same external #thermochemistry library so that all observed differences can be attributed to the underlying numerical methods. Results from eight benchmark cases are reported. Four cases are selected to verify the implementation of chemistry, transport properties, catalytic boundary conditions, and shock capturing. Four validation cases consider blunt geometries with adiabatic/isothermal and inert/catalytic/ablative boundary conditions. Overall, the results obtained with the IB solvers are in very good agreement with the reference data. Discrepancies arise with ghost-cell methods for cases with large temperature or concentration gradients at the wall and are attributed to mass conservation errors. Only a strictly conservative cut-cell IB method is on par with body-fitted grid methods. The link below takes you to my review of this paper, and the state of the art in #hypersonic #aerodynamics #computational #fluiddynamics #CFD #codes.

heat transfer concept

I'm excited to announce that our new I'm excited to announce that our new #Nature Paper entitled "Thermal performance augmentation in a pipe employing hybrid nanofluid and a plate as turbulator with V-shaped double-winglet ribs " has been published in the #Scientific Reports. It's a #Q1 journal with a 5 years Impact Factor of 5, March , 2024   This article employs a plate with V-shape ribs inside a #tube as #turbulator to augment the #heat_transfer rate. The utilized #vortex generators are double-winglets arranged in a #V_shape placed on both sides of the plate. The proposed system’s suggested working #fluids are water-based #hybrid_nanofluids, including #Al2O3–Cu/water, Cu–CuO/water, and #Cu–TiO2/water. This work involves a numerical evaluation of the effects of the type and volume concentration of the examined hybrid #nanofluids on the enhancement of heat transfer. The experimental results are used to validate the numerical model. It is worth mentioning that all the obtained numerical results are compared with the simple tube, without any turbulator (#vortex generator) and in the presence of water instead of the hybrid nanofluids. I would like to sincerely thank Dr.Zhongmian Fan for supervising this project. And Special thanks to Dr.Lingxiao Wang for his constructive technical support during this research. I would like to express my sincere gratitude to and for their valuable collaboration during this article’s road.   You can find and download this paper from the link below: B2n.ir/b95734   What’s your opinion about the future of the “ Hybrid Nano Fluids”?

#mechaniverse "Capillary condensation" is a fascinating process that occurs in porous materials. Let me break it down for you: 1. Definition: Capillary condensation refers to the multilayer adsorption of vapor from the gas phase into a porous medium (such as a material with tiny pores or channels). As this process continues, the "pore spaces become filled with condensed liquid" from the vapor phase. 2. Unique Aspect: What makes capillary condensation intriguing is that it happens below the saturation vapor pressure (Psat) of the pure liquid. In other words, vapor condenses even when it's not at its maximum pressure. 3. Why Does It Occur? Inside the confined space of a capillary (which can be any small pore or channel), there are increased van der Waals interactions between vapor molecules. These interactions lead to vapor condensation below Psat, creating a meniscus (a curved liquid-vapor interface) within the capillary. The formation of this meniscus allows for "equilibrium" below Psat. 4. Mathematical Insights: The Young-Laplace equation describes how the shape of the meniscus depends on the surface tension of the liquid and the capillary's geometry. The Kelvin equation provides a relation for the difference between the equilibrium vapor pressure and Psat in the presence of a curved meniscus. 5. Applications: Capillary condensation plays a crucial role in both natural and synthetic porous structures like catalysts. Scientists use this concept to determine pore size distribution and surface area through adsorption isotherms. It's also relevant in synthetic processes like sintering of materials However, it can sometimes cause issues in applications like atomic-force microscopy and microelectromechanical systems. All in all, capillary condensation is like a hidden dance of molecules within tiny spaces, defying the usual vapor pressure rules! For more detailed information check this exquisite demonstration: https://lnkd.in/eWgBUMDQ 🔥Follow me on LinkedIn: https://lnkd.in/dyJ4T5Dn   🔥Join me on telegram: https://t.me/firedheater #mechanicalengineer #processdesign #firedheater #catalysts #PorousMaterial

Excited to share our latest work published in Physics of Fluids: "Gas dynamics at starting and terminating phase of a supersonic exhaust diffuser with a conical nozzle"! This research investigates the process of starting and breakdown of second throat diffuser during high-altitude test of conical nozzle. The subscale experimental setup includes a conical nozzle with an expansion ratio of 53, plus a second throat diffuser with a contraction ratio of 1.85, using compressed air as the working fluid. Numerical simulation has been employed to identify the flow physics during the unsteady process of start-up and breakdown. https://lnkd.in/gQCCvZKF

RFNC VNIITF conducts research to ensure hydrogen explosion safety of NPPs with VVER-type reactors. An experimental facility was designed to conduct experiments under conditions close to accident conditions at NPPs - high temperatures and pressures and a large amount of water steam. Thermal insulation and wall heating system allows maintaining the necessary conditions inside the facility and avoiding steam condensation on construction elements. Facility volume ~14 m3, height 5 m. The flame source size increasing leads to the ascent speed becomes greater than the laminar flame speed. Therefore, it becomes possible to observe large-scale flame propagation effects. When designing the facility, the following types of experiments were planned: 1 - Experiments on the gas mixture stirring by condensing steam droplets caused by the steam displacement by hydrogen from the region with established thermodynamic equilibrium. 2 - Studies of flame propagation along/against the gravity direction in homogeneous mixtures and in mixtures with positive/negative hydrogen and steam concentration gradients. 3 - Testing of passive autocatalytic hydrogen recombiners at different hydrogen and steam concentrations. Continuous measurement of pressure, temperatures and humidity, as well as multiple gas sampling at the filling, pre-combustion and post-combustion stages, windows for high-speed Schlieren imaging techniques allow obtaining results necessary for validation of mathematical models and CFD codes. The animation shows the temperature cut plot calculation result. The initial conditions are close to one of the experiments performed. In the upper half of the chamber (in the picture on the left) there is a homogeneous composition of ~30% hydrogen, ~30% steam and air. Air predominates in the lower part. Combustion is initiated in the upper part of the chamber. One can see the flame stretching along the camera axis, which can be either a numerical effect (coarse mesh, 1/R features) or a physical effect. #cfd #physics #combustion #hydrogen #NPP #safety #experiment #validation

#article #update I am happy to share my recently published article, one of the most awaited articles from my doctoral thesis. In this work, we investigated the instability of mixed convection in an annular domain filled with a porous medium under non-axisymmetric finite-amplitude disturbance. The numerical results were validated with published experimental as well as numerical results for a special case of purely viscous media flow in annular geometry. The instability boundary as a function of Reynolds number, medium permeability, and curvature parameter has been examined in this study for both two-dimensional and three-dimensional disturbances. In contrast to the channel flow results, we found that the inclusion of curvature leads to a large range of Reynolds in which subcritical instability exists. Increasing the gap between cylinders leads to an increase in the threshold amplitude below which the flow remains nonlinearly stable. In comparison to the channel flow through porous media and annular flow in a purely viscous medium, a different feature of temperature distribution has been predicted in annular flow through a porous medium. This work provides a general overview of the flow instability in a porous duct and opens the door to exploring other aspects of flow instability in an annular porous duct. We extend our gratitude to the anonymous reviewers for their appreciation and valuable suggestions and comments. We also welcome your feedback and critiques on our article. #hydrodynamics #stability #porous #media