Matthew R. Coburn¹, Charlie Young², Chris Smith², Graham Schultz², Miguel Robayo³, Zheng-Tong Xie^1,*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.3, pp. 547-562, 2024, DOI:10.32604/fdmp.2023.028601

Abstract A prototype cleanroom for hazardous testing and handling of satellites prior to launcher encapsulation, satisfying the ISO8 standard has been designed and analyzed in terms of performances. Unsteady Reynolds Averaged Navier-Stokes (URANS) models have been used to study the related flow field and particulate matter (PM) dispersion. The outcomes of the URANS models have been validated through comparison with equivalent large-eddy simulations. Special attention has been paid to the location and shape of the air intakes and their orientation in space, in order to balance the PM convection and diffusion inside the cleanroom. Forming a cyclone-type flow pattern inside the… More >

Junying Wei^*, Gang Li, Chenrui Zhang, Wenwen Chang, Jidai Wang

Frontiers in Heat and Mass Transfer, Vol.21, pp. 199-214, 2023, DOI:10.32604/fhmt.2023.041793

Abstract To study the complex internal flow field variation and output characteristics of a variable base radius scroll expander, this paper uses dynamic mesh techniques and computational fluid dynamics (CFD) methods to perform transient numerical simulations of a variable base radius scroll expander. Analysis of the flow field in the working cavity of a variable base radius scroll expander at different spindle angles and the effect of different profiles, speeds and pressures on the output characteristics of the scroll expander. The results of the study show that due to the periodic blocking of the inlet by the orbiting scroll, the fluid… More >

D. Lourdu Immaculate^a , R. Muthuraj^b,*, Anant Kant Shukla^c, S. Srinivas^d

Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-14, 2016, DOI:10.5098/hmt.7.12

Abstract This article aims to examine the MHD unsteady flow of Williamson nanofluid in a vertical channel filled with a porous material and oscillating wall temperature. The modeling of this problem is transformed to ordinary differential equations by collecting the non-periodic and periodic terms and then series solutions are obtained by using a powerful method known as the homotopy analysis method (HAM). The influence of involved parameters on heat and mass transfer characteristics of the fluid flow is computed and presented graphically. Further, variations on volume flow rate, coefficient of skin friction, heat transfer rate and mass transfer rate are also… More >

Odelu Ojjela^*, K. Pravin Kashyap, N. Naresh Kuma, Samir Kumar Das

Frontiers in Heat and Mass Transfer, Vol.7, pp. 1-9, 2016, DOI:10.5098/hmt.7.32

Abstract This article presents an unsteady incompressible Upper Convected Maxwell (UCM) fluid flow with temperature dependent thermal conductivity between parallel porous plates which are maintained at different temperatures varying periodically with time. Assume that there is a periodic suction and injection at the upper and lower plates respectively. The governing partial differential equations are reduced to non linear ordinary differential equations by using similarity transformations and the solution is obtained using differential transform method. The effects of various fluid and geometric parameters on the velocity components, temperature distribution and skin friction are discussed in detail through graphs. More >

N. Vijaya^a,*, Y. Hari Krishna^a , K. Kalyani^b, G.V.R. Reddy^a

Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-11, 2018, DOI:10.5098/hmt.11.19

Abstract The present paper deals with the thermo physical properties of a Casson fluid through an oscillating vertical wall embedded through porous medium under the influence transverse magnetic field, radiation, constant heat source and first order chemical reaction. The radiative heat loss is modelled by using Rosseland approximation. Similarity variables were used to convert the partial differential equations into ordinary differential equation. The transformed ordinary differential equations are solved numerically using Runge - Kutta -Fehlberg method with shooting technique. In order to get perfect perception of the flow pattern we obtain the graphs of axial velocity, temperature and concentrations profiles for… More >

Elyazid Flilihi, Mohammed Sriti, Driss Achemlal

Frontiers in Heat and Mass Transfer, Vol.12, pp. 1-10, 2019, DOI:10.5098/hmt.12.12

Abstract A numerical investigation is performed to analyze the transient laminar free convection over an isothermal inclined plate embedded in a saturated porous medium with the viscous dissipation effects. The flow in the porous medium is modeled with the Darcy-Brinkman- Forchheimer model, taking into account the convective term. The dimensionless nonlinear partial differential equations are solved numerically using an explicit finite difference method. The effects of different parameters: (1 ≤ Re ≤ 10 ; 10⁻² ≤ Da ≤ 10 ; 0 ≤ Gr ≤ 50 ; 0 ≤ F r ≤ 3 ; 0 ≤ Ec ≤ 1 ; 0 ≤… More >

Muhammad A. Sadiq^1,2,*, Nadeem Abbas³, Haitham M. S. Bahaidarah⁴, Mohammad Amjad⁵

FDMP-Fluid Dynamics & Materials Processing, Vol.19, No.2, pp. 471-486, 2023, DOI:10.32604/fdmp.2022.021133

Abstract We present the results of an investigation into the behavior of the unsteady flow of a Casson Micropolar nanofluid over a shrinking/stretching curved surface, together with a heat transfer analysis of the same problem. The body force acting perpendicular to the surface wall is in charge of regulating the fluid flow rate. Curvilinear coordinates are used to account for the considered curved geometry and a set of balance equations for mass, momentum, energy and concentration is obtained accordingly. These are turned into ordinary differential equations using a similarity transformation. We show that these equations have dual solutions for a number… More >

Andrianantenaina Marcelin Hajamalala^1,*, Ratovonarivo Noarijaona¹, Zeghmati Belkacem²

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.6, pp. 1737-1748, 2022, DOI:10.32604/fdmp.2022.022047

Abstract This work deals with the modeling of the unsteady Newtonian fluid flow associated with an open cylindrical reservoir. This reservoir presents a hole on the right bottom wall. Fluid volume variation, heat and mass transfers are neglected. The unsteady governing equations are based on the conservation of mass and momentum. A finite volume technique is used to solve the non-dimensional equations and related boundary conditions. The algebraic system of equations resulting from the discretization process are solved by means of the THOMAS algorithm. For pressure-velocity coupling, the SIMPLE algorithm (Semi Implicit Method for Pressure Linked Equations) is used. Results for… More >

Ting Zhang¹, Denghao Wu^1,2,*, Shijun Qiu², Peijian Zhou¹, Yun Ren³, Jiegang Mou¹

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.5, pp. 1349-1361, 2022, DOI:10.32604/fdmp.2022.019617

Abstract Stall phenomena increase the complexity of the internal flow in centrifugal pump impellers. In order to tackle this problem, in the present work, a large eddy simulation (LES) approach is applied to determine the characteristics of these unstable flows. Moreover, a vorticity identification method is used to characterize quantitatively the vortex position inside the impeller and its influencing area. By comparing the outcomes of the numerical simulations and experimental results provided by a Particle Image Velocimetry (PIV) technique, it is shown that an apparent “alternating stall” phenomenon exists inside the impeller when relatively small flow rate conditions are considered. The… More >

Senchun Miao^1,2,*, Hongbiao Zhang¹, Wanglong Tian¹, Yinqiang Li²

FDMP-Fluid Dynamics & Materials Processing, Vol.17, No.6, pp. 1021-1036, 2021, DOI:10.32604/fdmp.2021.016925

Abstract To study the unsteady flow and related energy conversion process in the volute of a pump-as-turbine (PAT) device, six different working conditions have been considered. Through numerical calculation, the spatio-temporal variation of static pressure, dynamic pressure, total pressure and turbulent energy dissipation have been determined in each section of the volute. It is concluded that the reduction of the total power of two adjacent sections of the PAT volute is equal to the sum of the power lost by the fluid while moving from one section to the other and the power output from the two adjacent sections. For a… More >