SAURABH SAXENA^a, PRATEEK MALIK^a, GEETHA SESHADRI^a,*, AJAY K. TYAGI^a, UTTAM KUMAR MANDAL^b

Journal of Polymer Materials, Vol.36, No.1, pp. 39-51, 2019, DOI:10.32381/JPM.2019.36.01.4

Abstract Medium molecular weight liquid perfluoropolyethers (840 u to 1372 u) were synthesized by photopolymerization of hexafluoropropylene (HFP) in the presence of oxygen. Effects of various reaction parameters such as temperature, pressure, UV wattage and reaction time on yield, viscosity and molecular weight of PFPEs were studied. Out of all the parameters, the effect of reaction temperature was found the most significant on molecular weight of PFPEs. By increasing reaction temperature, viscosity and molecular weight of PFPEs where decreased. By increasing the wattage of the lamp, viscosity and molecular weight of PFPEs where also decreased. PFPEs obtained from reactions were subjected… More >

Victor Kozlov^1,*, Vladimir Saidakov¹, Nikolai Kozlov²

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.4, pp. 693-703, 2024, DOI:10.32604/fdmp.2024.048068

Abstract The behavior of two immiscible low-viscosity liquids differing in density and viscosity in a vertical flat layer undergoing modulated rotation is experimentally studied. The layer has a circular axisymmetric boundary. In the absence of modulation of the rotation speed, the interphase boundary has the shape of a short axisymmetric cylinder. A new effect has been discovered, under the influence of rotation speed modulation, the interface takes on a new dynamic equilibrium state. A more viscous liquid covers the end boundaries of the layer in the form of thin films, which have the shape of round spots of almost constant radius;… More >

Hanumesh Vaidya¹, Fateh Mebarek-Oudina^2,*, K. V. Prasad¹, Rajashekhar Choudhari³, Neelufer Z. Basha¹, Sangeeta Kalal¹

Frontiers in Heat and Mass Transfer, Vol.22, No.1, pp. 65-78, 2024, DOI:10.32604/fhmt.2024.047879

Abstract This investigation aims to analyze the effects of heat transport characteristics in the unsteady flow of nanofluids over a moving plate caused by a moving slot factor. The BRS variable is utilized for the purpose of analyzing these characteristics. The process of mathematical computation involves converting the governing partial differential equations into ordinary differential equations that have suitable similarity components. The Keller-Box technique is employed to solve the ordinary differential equations (ODEs) and derive the corresponding mathematical outcomes. Figures and tables present the relationship between growth characteristics and various parameters such as temperature, velocity, skin friction coefficient, concentration, Sherwood number,… More > Graphic Abstract

Muhammad Abaid Ur Rehman^1,*, Muhammad Asif Farooq¹, Ahmed M. Hassan²

Frontiers in Heat and Mass Transfer, Vol.22, No.1, pp. 263-286, 2024, DOI:10.32604/fhmt.2023.044587

Abstract This paper proposes a mathematical modeling approach to examine the two-dimensional flow stagnates at over a heated stretchable sheet in a porous medium influenced by nonlinear thermal radiation, variable viscosity, and MHD. This study’s main purpose is to examine how thermal radiation and varying viscosity affect fluid flow motion. Additionally, we consider the convective boundary conditions and incorporate the gyrotactic microorganisms equation, which describes microorganism behavior in response to fluid flow. The partial differential equations (PDEs) that represent the conservation equations for mass, momentum, energy, and microorganisms are then converted into a system of coupled ordinary differential equations (ODEs) through… More >

R. J. Johnson^∗, R. Pitchumani^†

Frontiers in Heat and Mass Transfer, Vol.1, No.1, pp. 1-9, 2010, DOI:10.5098/hmt.v1.1.3007

Abstract Much research is currently being performed with carbon nanotube additives to neat resin systems to enhance properties such as thermal and electrical conductivity, strength, modulus and damping. Fabrication of parts based on carbon nanotube filled resin systems requires information on their cure kinetics and rheology, which has been relatively less studied so far. This work presents an extensive experimental study that systematically characterizes the cure kinetics and viscosity as a function of degree of cure and temperature of EPON 815C/EPICURE 3274 epoxy resin system laden with carbon nanotubes. Studies are conducted to determine the effects of the carbon nanotube loading… More >

Lei Zhu^1,2, Bin Liu², Xuewei Liu^2,*, Wei Deng¹, Wenjie Yao¹, Ying Fan¹

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.2, pp. 401-427, 2024, DOI:10.32604/fdmp.2023.041444

Abstract To analyze the effects of a time-varying viscosity on the penetration length of grouting, in this study cement slurries with varying water-cement ratios have been investigated using the Bingham’s fluid flow equation and a discrete element method. A fluid-solid coupling numerical model has been introduced accordingly, and its accuracy has been validated through comparison of theoretical and numerical solutions. For different fracture forms (a single fracture, a branch fracture, and a fracture network), the influence of the time-varying viscosity on the slurry length range has been investigated, considering the change in the fracture aperture. The results show that under different… More >

Swetha Lanka¹, Venkata Subrahmanyam Sajja^1,*, Dhaneshwar Prasad²

Frontiers in Heat and Mass Transfer, Vol.21, pp. 385-405, 2023, DOI:10.32604/fhmt.2023.042544

Abstract An attempt is made to analyse some lubrication characteristics of rigid cylindrical asymmetric rollers under adiabatic and isothermal boundaries with rolling and sliding motion lubricated by a non-Newtonian incompressible Bingham plastic fluid under the behaviour of line contact. Here the lower surface is considered to move quicker than that of the upper surface; and the Roelands viscosity model is considered and assumed to depend upon the fluid pressure and the mean film temperature. The governing equations for fluid flow such as equations of motion with continuity and the momentum energy equation are solved using Runge-Kutta forth order and MATLAB is… More >

Vandana Bisht^*

Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-7, 2016, DOI:10.5098/hmt.7.19

Abstract In this paper the steady laminar magneto hydrodynamic (MHD) mixed convection boundary layer flow towards a vertical stretching sheet with variable fluid viscosity, radiation and in the presence of Dufour’s effect have been investigated. The governing partial differential equations are transformed into set of ordinary differential equations using similarity transformation, and then these equations have been solved numerically using Runge- Kutta method with shooting technique. Results shows that magnitude of skin friction coefficient decreases, while magnitude of heat transfer coefficient and mass transfer coefficient increases with decreasing values of viscosity variation parameter for the case of opposing flow. But in… More >

S.V. Subhashini^a,* , Nancy Samuel^b

Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-7, 2016, DOI:10.5098/hmt.7.29

Abstract The aim of this paper is to present non-similar solutions of a steady laminar compressible boundary layer flow past a long thin circular cylinder including the effects of wall enthalpy and surface mass transfer. The governing equations along with the boundary conditions are first converted into dimensionless form by a non-similar transformation, and then the resulting system of coupled non-linear partial differential equations is solved by an implicit finite difference scheme in combination with the quasi-linearization technique. The increase in the value of power law variation of viscosity causes an increase in the boundary layer thicknesses of both the velocity… More >

Qingyun Zeng^1,2, Mingxin Zheng^1,*, Dan Huang²

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.12, pp. 2981-3005, 2023, DOI:10.32604/fdmp.2023.029427

Abstract A complex interface exists between water flow and solid particles during hydraulic soil erosion. In this study, the particle discrete element method (DEM) has been used to simulate the hydraulic erosion of a granular soil under moving bed conditions and surrounding terrain changes. Moreover, the weakly compressible smoothed particle hydrodynamics (WCSPH) approach has been exploited to simulate the instability process of the free surface fluid and its propagation characteristics at the solid–liquid interface. The influence of a suspended medium on the water flow dynamics has been characterized using the mixed viscosity concept accounting for the solid–liquid mixed particle volume ratio.… More > Graphic Abstract