This work investigates mixed convection in a lid-driven cavity. This cavity is filled with nanofluid and subjected to a magnetic field. The concentric ovoid cavity orientation (γ), 0–90°, and undulation number (N), 1–4, are considered. The Richardson number (Ri) varies between 1 and 100. The nanofluid volume fraction (φ) ranges between 0 and 0.08%. The effect of the parameters on flow, thermal transport, and entropy generation is illustrated by the stream function, isotherms, and isentropic contours. Heat transfer is augmented and the Nusselt number rises with higher Ri, γ, N, and φ. The simulations show that the heat transfer is responsible for entropy generation, while frictional and magnetic effects are marginal.

/pdf/hydrothermal-and-entropy-investigation-of-nanofluid-natural-1rzbg1j2.pdf

Hydrothermal and Entropy Investigation of Nanofluid Natural Convection in a Lid-Driven Cavity Concentric with an Elliptical Cavity with a Wavy Boundary Heated from Below

In the existent study, combined magneto-convection heat exchange in a driven enclosure having vertical fin was analyzed numerically. The finite element system-based GWR procedure was utilized to determine the flow model’s governing equations. A parametric inquiry was executed to review the influence of Richardson and Hartmann numbers on flow shape and heat removal features inside a frame. The problem’s resulting numerical outcomes were demonstrated graphically in terms of isotherms, streamlines, velocity sketches, local Nusselt number, global Nusselt number, and global fluid temperature. It was found that the varying lengths of the fin surface have a substantial impact on flow building and heat line sketch. Further, it was also noticed that a relatively fin length is needed to increase the heat exchange rate on the right cool wall at a high Richardson number. The fin can significantly enhance heat removal performance rate from an enclosure to adjacent fluid.

Influence of Fin Length on Magneto-Combined Convection Heat Transfer Performance in a Lid-Driven Wavy Cavity

In computational fluid dynamics (CFD), the mathematical description of a physical phenomenon that involves fluid flow, combustion, and chemical reaction is combined with a numerical solution of the problem via the use of a computer process. Computational fluid dynamics has emerged as a critical tool for comprehending and forecasting the behavior of reacting flows, which are fundamentally complicated systems involving the intricate interplay of chemical kinetics and fluid mechanics. Among the numerous open source CFD packages, the widely used C++ finite volume simulation toolbox OpenFOAM (Open-Source Field Operation and Manipulation) has a number of advantages, including an object-oriented framework, the ease with which multiphysics modules can be added, and its free availability. However, numerous shortcomings have been identified regarding its application to chemically reacting flows, most notably incomplete splitting schemes, inadequate ordinary differential equation (ODE) solvers for stiff chemistry, and oversimplified mixture transients. This article focuses on the combustion flow in an intake manifold. A sample intake manifold consists of two inlets and one outlet. The finite volume method is used for computing the mathematical modeling developed for combustion. The focus of the attention will be the demonstration of the structure of the flame. The energy deposition and pressure near the outlet are higher. The results are compared and found a good agreement between OpenFOAM and DUNE (Distributed and Unified Numerics Environment) numerics. 

https://link.springer.com/content/pdf/10.1140/epjs/s11734-022-00606-6.pdf

OpenFOAM for computational combustion dynamics

This article demonstrates the feasibility of porous separation on the performance of displacement ventilation in a rectangular enclosure. A jet of fresh air enters the cavity through an opening at the bottom of the left wall and exits through an opening at the top of the right wall. The porous separation is placed in the center of the cavity and its height varies between 0.2 and 0.8 with three values of thickness, 0.1, 0.2, and 0.3. The heat transfer rate was calculated for different intervals of Darcy (10−6 ≤ Da ≤ 10), Rayleigh (10 ≤ Ra ≤ 106), and Reynolds (50 ≤ Re ≤ 500) numbers. The momentum and the energy equations were solved by the lattice Boltzmann method with multiple relaxation times (LB-MRT). Schemes D2Q9 and D2Q5 were chosen for the velocity and temperature fields, respectively. For porous separation, the generalized Darcy–Brinkman–Forchheimer model was adopted. It is represented by a term added in the standard LB equations. For the dynamic domain, numerical simulations revealed complex flow structures depending on all control parameters. The results showed that the thermal field, mainly in the second compartment, is very dependent on the size and permeability of the porous separation. However, they have no influence on the transfer rate.

/pdf/analysis-of-thermal-performances-in-a-ventilated-room-using-1j0u7hdl.pdf

Analysis of Thermal Performances in a Ventilated Room Using LBM-MRT: Effect of a Porous Separation

The present experimental paper is officiated to study the heat characteristics and performance of air flow through a square cross-sectional heated channel under natural heat convection conditions. The influence of baffles arrangement and perforated baffles on the rate of heat transfer through a channel are studied. Four cases of a heated channels are studied, one is a plain channel and other three channels with a baffle namely, three inline baffles, three staggered baffles and three staggered perforated baffles arrangements. The outer tested channels surfaces are electrically heated with a constant surface heat flux condition. All tested channels are fabricated by cold forming with constant dimensions using aluminum plate has thickness of 1.0 mm. The heat performance is assessed for all tested channels. The results of present paper are approved than the available data in the previous paper and a good convergence are noticed. Obtained experimental results appear that a three staggered perforated baffles arrangement is a best selection as it improves heat transfer rate in expression of Nusselt number, it higher about 22% to 27% than that the plain channel for same conditions.

Study of Baffles Arrangement Influence on the Natural Convection into a Heated Square Channel

This research reports the outcome of a numerical investigation of convection in ventilation square cavities contains parallel insulated baffles. The left and right walls of the cavity are kept at the high temperature. Whereas the top, bottom cavity walls, parallel baffles are adiabatic. The opening slots are positioned at the top, bottom corners of the hot vertical walls. The governing Navier-Stokes equations are formulated in the form of vorticity- stream functions. The finite difference method is used to find the values of the primitive variables. The effects of baffles size (Sb − 0.25, 0.50, 0.75), 3 various positions of the parallel baffle, Rayleigh number (103 − 106), Reynolds number (30, 300, 600) are discussed with the flow fields, isotherms, and Nusselt number. It is found that the behavior of ventilation cavities does not only depend on the size of the baffles and its positions. It highly depends on the configuration of the ventilation cavity too. Further, the flow fields are restricted by the largest baffles size of Sb = 0.75.

/pdf/numerical-investigation-of-open-cavities-with-parallel-5cphbtm01z.pdf

Numerical Investigation of Open Cavities with Parallel Insulated Baffles


 
 
 Iron deficiency (ID) impacts ∼50% of heart failure (HF) patients [1] and is a risk factor and strong predictor for death and mortality with or without anaemia [2]. Oral iron appears to be ineffective whilst intravenous iron (IV-iron) has proven to be efficacious however data is primarily from a Caucasian population [3] despite ID being more prevalent amongst Asians. The I4RON-HF study assesses efficacy of high-dose IV-iron versus oral iron in stable outpatients and inpatients amongst an Asian population recovering from episodes of decompensated HF.
 
 
 
 This is a single-centre randomized controlled study, where patients who had symptomatic heart failure (Ejection Fraction <50% and New York Heart Association class 2–3) were randomized into two groups. The intervention arm received anywhere from 500mg to 1500mg of IV Iron Isomaltoside as a single infusion, whereas the control arm received routine iron supplements.
 The primary study endpoint was the percentage of patients achieving iron repletion at 4,8 and 12 months after enrolment. Secondary endpoints included clinical parameters (6-minute walk test, NYHA status and 2D-Echocardiogram), and biochemical parameters (Serum NTproBNP, Cardiac Troponin-T and hemogloblin) at 4,8 and 12 months.
 
 
 
 A total of 65 patients were enrolled (male 55%), 33 in the interventional arm and 32 in the control arm. There were no patients lost to follow up. 96.9% of patients in the IV Iron arm achieved the primary endpoint at 4 months, compared to 68.7% in the control group. These findings we consistent at 8 months (90.9% vs 65.6%) and 12 months (90.9% vs 56.2%). Looking at the secondary endpoints, the IV Iron cohort recorded a 11.14% increase in Hemogloblin levels versus the control arm which recorded a reduction of 16.23%. There was also lower NTproBNP levels in the IV iron group (81.6% reduction) versus the control group (66.3% reduction). Clinically, the patients who received IV iron had a 42.98% increase in their 6-minute walk test from baseline, compared to an increase of 8.61% in the control arm. There were no significant echocardiographic changes.
 
 
 
 These findings in our single-centre study support the efficacy of IV iron over oral supplements in the treatment of iron deficiency amongst Asian heart failure patients. The secondary endpoints also indicate better clinical and biochemical outcomes when iron stores are successfully repleted. Lastly, this study demonstrates the feasibility and safety of outpatient administration of high-dose IV-iron. Results from large-scale clinical studies looking at hard endpoints (mortality, HF hospitalization) are expected to further advance understandings.
 
 
 
 Type of funding sources: Foundation. Main funding source(s): National Heart Institute (Institut Jantung Negara) FoundationCompai Pharma


/pdf/the-i4ron-hf-study-intravenous-iron-isomaltoside-for-s0yn0fck.pdf

Gokulavani Palaniappan

Papers

Numerical Investigation of Open Cavities with Parallel Insulated Baffles

The I4RON-HF study, Intravenous Iron Isomaltoside for Inpatients veRsus Outpatient Asians with Heart Failure

Single center experience of transcatheter aortic valve implantation in severe aortic stenosis (2009–2021)