Numerical Study of the Pressure Drop in a Flame Arrestor Using a Porous Media Model

2020 ◽  
Author(s):  
Hoden A. Farah ◽  
Frank K. Lu ◽  
Jim L. Griffin
Keyword(s):  
Numerical Simulation ◽  
Porous Media ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Small Scale ◽  
Forchheimer Equation ◽  
Flow Equations ◽  
Numerical Studies ◽  
Porous Media Model ◽  
Empirical Coefficients

Abstract A numerical study of the flow characteristics of a crimped flame arrestor element was conducted using a porous media model. The porous zone was modeled using the Forchheimer equation. The Forchheimer equation was incorporated into the governing conservation equations as a momentum sink. A small-scale crimped flame arrestor element was tested to determine the empirical coefficients in the Forchheimer equation. The numerical simulation result using this porous media model was verified using experimental data. The flow characteristics of a four-inch detonation flame arrestor with the same crimp design as the small-scale sample, was simulated using the porous media model. The numerical simulation flow data were compared against experimental values and agreed to within five percent. The method used to determine the Forchheimer coefficients and the experimental test setup are described in detail. The application of the Forchheimer equation into the governing flow equations is presented. The challenges and limitation of numerical studies in flame arrestors applications are discussed. The simplification gained by using the porous media model in flame arrestor numerical studies is presented.

scholarly journals A Porous Media Model for the Numerical Simulation of Acoustic Attenuation by Perforated Liners in the Presence of Grazing Flows

2021 ◽  
Vol 11 (10) ◽  
pp. 4677
Author(s):  
Jianguo Wang ◽  
Philip Rubini ◽  
Qin Qin
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Porous Media ◽  
Traditional Approach ◽  
Normal Incidence ◽  
Design Tool ◽  
Small Scale ◽  
Mean Flow ◽  
Acoustic Attenuation ◽  
Porous Media Model

In this paper, a novel model is proposed for the numerical simulation of noise-attenuating perforated liners. Effusion cooling liners offer the potential of being able to attenuate combustion instabilities in gas turbine engines. However, the acoustic attenuation of a perforated liner is a combination of a number of interacting factors, resulting in the traditional approach of designing perforated combustor liners relying heavily on combustor rig tests. On the other hand, direct computation of thousands of small-scale holes is too expensive to be employed as an engineering design tool. In recognition of this, a novel physical velocity porous media (PVPM) model was recently proposed by the authors as a computationally less demanding approach to represent the acoustic attenuation of perforated liners. The model was previously validated for the normal incidence of a sound wave by comparison with experimental data from impedance tubes. In this paper, the model is further developed for configurations where the noise signal propagates in parallel with the perforated liners, both in the presence and absence of a mean flow. The model is significantly improved and successfully validated within coexisting grazing and bias flow scenarios, with reference to a series of well-recognized experimental data.

scholarly journals Study on Flow Characteristics of Working Medium in Microchannel Simulated by Porous Media Model

Micromachines ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 18
Author(s):  
Yufan Xue ◽  
Chunsheng Guo ◽  
Xiaoxiao Gu ◽  
Yanfeng Xu ◽  
Lihong Xue ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Porous Media ◽  
Capillary Force ◽  
Heat Dissipation ◽  
Flow Behavior ◽  
Computational Cost ◽  
Flow Characteristics ◽  
Two Phase ◽  
Microchannel Array ◽  
Porous Media Model

As a phase change evaporator, a microchannel array heat exchanger is of great significance in the field of microscale heat dissipation. The performance of which strongly depends on the flow resistance, capillary force, and other factors. In order to improve the heat dissipation efficiency, it is necessary to perform an in-depth study of the characteristics of microchannel flow using numerical simulation. However, the current simulation model requires high computational cost and long simulation time. To solve this problem, this paper simplifies the numerical simulation of the rectangular parallel array microchannels by building the basic flow model based on the concept of porous media. In addition, we explore the effect of aspect-ratio (AR), hydraulic diameter, inlet velocity, and other parameters of fluid flow behavior inside the microchannels. Meanwhile, a user-defined function (UDF) is formulated to add the capillary force into the model to introduce capillary force into the porous media model. Through the above research, the paper establishes the porous media model for single-phase and gas-liquid two-phase flow, which acts as a simplification of microchannel array simulation without grossly affecting the results obtained. In addition, we designed and manufactured experiments using silicon-based microchannel heat exchangers with different-ratios, and combined with the visualization method to measure the performance of the device and compared them with simulation results. The theoretical model is verified through the suction experiment of array microchannel evaporator capillary core. The simplified model of microchannel array significantly saves the computational cost and time, and provides guidance for the related experimental researches.

Numerical Simulation Study on Battery-Casing Sealing Considering Rubber Aging

2020 ◽  
Vol 36 (6) ◽  
pp. 955-969
Author(s):  
Yijie Huang ◽  
Fei Guo ◽  
Yuchao Ke ◽  
Fangyong Wu ◽  
Xiaohong Jia ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Porous Media ◽  
Circular Arc ◽  
Sealing Material ◽  
Sealing Performance ◽  
Porous Media Model ◽  
New Energy ◽  
Key Factor ◽  
Grid Independence ◽  
New Energy Vehicles

ABSTRACTBattery-casing sealing is the key factor for secure travel of new energy vehicles. We constructed a relatively accurate mechanical-simulation model by selecting a constitutive model, analyzing the influence of thermal elongation, verifying the grid-independence and comparing numerically by the pressure-measurement film on the basis of studying the physical performance of a certain type of sealing material that had been used in battery-casings after aging. Based on a porous-media model and combined with changes of macroscopic and microscopic contact characteristics of materials at different times after aging, the evolution rule of sealing performance with time was analyzed quantitatively by calculating the leakage. By analyzing the structure of circular arc bulge on the surface of sealing material, the radius of circular arc bulge with better sealing performance was obtained, which could reduce the leakage of sealing structure during the material’s lifecycle.

Numerical Study of Wave Slamming on an Oscillating Flap

2014 ◽  
Author(s):  
Yanji Wei ◽  
Alan Henry ◽  
Olivier Kimmoun ◽  
Frederic Dias
Keyword(s):  
Stokes Equations ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Ocean Waves ◽  
Navier Stokes ◽  
Time Step ◽  
Navier Stokes Equations ◽  
Numerical Studies ◽  
Wave Slamming ◽  
Volume Method

Bottom hinged Oscillating Wave Surge Converters (OWSCs) are efficient devices for extracting power from ocean waves. There is limited knowledge about wave slamming on such devices. This paper deals with numerical studies of wave slamming on an oscillating flap to investigate the mechanism of slamming events. In our model, the Navier–Stokes equations are discretized using the Finite Volume method with the Volume of Fluid (VOF) approach for interface capturing. Waves are generated by a flap-type wave maker in the numerical wave tank, and the dynamic mesh method is applied to model the motion of the oscillating flap. Basic mesh and time step refinement studies are performed. The flow characteristics in a slamming event are analysed based on numerical results. Various simulations with different flap densities, water depths and wave amplitudes are performed for a better understanding of the slamming.

Experimental and numerical study on a novel ribbed bracing system

2017 ◽  
Vol 21 (9) ◽  
pp. 1349-1360
Author(s):  
Ali Akbar Golafshani ◽  
Soheil Fallah ◽  
Mohammad Amin Sahafipourfard ◽  
Ali Arzeytoon ◽  
Vahab Toufigh
Keyword(s):  
Numerical Study ◽  
Absorption Capacity ◽  
Small Scale ◽  
Test Results ◽  
Residual Drift ◽  
Numerical Studies ◽  
Numerical Assessment ◽  
Story Drift ◽  
Bracing System ◽  
Length Reduction

In this article, the ribbed bracing system is proposed and evaluated through experimental and numerical studies. Ribbed bracing system is composed of a supplemental part with ribbed interfaces that is attached to a brace member and allows for its free length reduction to prevent the development of compressional forces responsible for buckling of the brace. Ribbed bracing system provides two different mechanisms: completely closed ribbed bracing system and improved-centering ribbed bracing system which are validated, in this study, through design, fabrication, and testing of small-scale specimens subjected to cyclic quasi-static loading. As verified by the test results, in improved-centering ribbed bracing system, nearly all compressive deformations are resisted through a self-centering mechanism; thus, smaller residual drift and energy absorption capacity are provided. In contrast, completely closed ribbed bracing system is ideal for maximizing the absorbed energy and minimizing the story drift while it leads to a rather large residual drift. Numerical assessment of an X-configured ribbed bracing system assembly employing the experimentally observed behavior also validates ribbed bracing system potentials for use in frame configurations.

An Investigation of Scale Variation in Multi-Layer Mini- and Micro-Channel Heat Sinks in Single Phase Flow Using a Two Equation Porous Media Model

2009 ◽  
Author(s):  
Bryan Hassell ◽  
Alfonso Ortega
Keyword(s):  
Porous Media ◽  
Heat Sink ◽  
Heated Surface ◽  
Base Material ◽  
Heat Sinks ◽  
Small Scale ◽  
Micro Channel ◽  
Porous Media Model ◽  
Microchannel Heat Sinks ◽  
Scale Variation

Research in liquid cooled mini- and micro-channel heat sinks is growing due to the potentially high heat fluxes that can be dissipated with such devices. Ostensibly, mini- or microchannel heat sinks are derivatives of more generalized porous structures. They are porous, but the pores are continuous and deterministic in structure, with well defined geometries created by etching or cutting channels into solid base material. As such, deterministic small scale heat sinks of this type lend themselves to modeling using the well-developed theories for saturated porous media. Based on the principle that physical problems contain multiple scales with multiple objectives, it is of interest to examine the possibility that allowing scale change away from the heated surface in a multi-layered heat sink would yield greater global benefits. Modeled as a saturated porous medium, scale variation in stacked multi-layer microchannel heat sinks has been explored using an experimentally verified two equation porous model. This paper compares and rates scaling parameters based on the pressure drop across the heat sink along with the unit thermal resistance.

The Numerical Simulation and Experimental Research of Combustor in Micro Thermophotovoltaic Systems

2014 ◽  
Vol 678 ◽  
pp. 576-581
Author(s):  
Chuang Li ◽  
Bin Xu ◽  
Jian Wu ◽  
Yi Cheng ◽  
Zhi Hao Ma
Keyword(s):  
Numerical Simulation ◽  
Porous Media ◽  
Cross Section ◽  
Flow Rate ◽  
Outlet Temperature ◽  
Contour Map ◽  
Average Temperature ◽  
Porous Media Model ◽  
Fluent Software ◽  
Temperature Contour

With the establishment of the appropriate porous media model of the combustor, temperature contour map on combustor cross section were simulated under the condition of different flow rate and different porosity in the Fluent software, and experimented to verify the simulation. The results show that: Flame core position moves toward the export with the increase of flow rate, but when the flow increases to a certain amount, the outlet temperature rises significantly. temperature distribution is the best when flow rate is 120 mL/min; With the decrease of the porosity, the flame core position moves to the entrance. Wall average temperature of the combustor is the highest when porosity is 0.4.

Numerical study of methane TPOX within a small scale Inert Porous Media based reformer

2014 ◽  
Vol 39 (9) ◽  
pp. 4311-4321 ◽  
Author(s):  
Miguel A.A. Mendes ◽  
José M.C. Pereira ◽  
José C.F. Pereira
Keyword(s):  
Porous Media ◽  
Numerical Study ◽  
Small Scale

scholarly journals Numerical study of heat flow characteristics of turbulent Taylor-Couette flow in slit wall mode

2021 ◽  
Vol 9 ◽  
Author(s):  
Dong Liu ◽  
◽  
Mohammed Mohammedsalih ◽  
Amponsah-Gyenin Nana Kofi ◽  
Shi-cheng Ding ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Couette Flow ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Simulation Method ◽  
Industrial Applications ◽  
Small Scale ◽  
Taylor Couette ◽  
Taylor Couette Flow

Heat transfer enhancement is by far an important component in the design of numerous industrial applications of Taylor-Couette flow including electric motors and particularly rotating machinery. To optimize the performances of these machines, superior knowledge of the fluid flow is vital to better estimate the heat transfer distribution. This study will specifically consider the effect the slit number and width possess on the distribution of turbulent Taylor-Couette flow and the resulting heat transfer correlation in the annulus of two concentric cylinders under varying conditions. A numerical simulation method is intended for the study using varying slit structure parameters of widths (2.5 ≤ w ≤ 7.5) mm and fitted with 6, 9 and 12 number of slits. The slit effect is then investigated under both isotherm and non-isotherm conditions considering the interactions between fluid flow regions in the mainstream area and the annulus. The small-scale vortex that appears in the annulus region improves the heat transferability between the fluid in the annulus and the main region as well as the heat transfer performance of the model with a gradual increase in Reynolds number.

A Review on Flow Characteristics of the Straight and Coiled Capillary Tubes

2021 ◽  
Vol 29 (03) ◽  
Author(s):  
Pravin Jadhav ◽  
Neeraj Agrawal
Keyword(s):  
Capillary Tube ◽  
Numerical Study ◽  
Flow Behavior ◽  
Flow Characteristics ◽  
Operating Conditions ◽  
Capillary Tubes ◽  
Numerical Studies ◽  
Geometric Conditions ◽  
Flow Characterization

A detailed literature review on the flow characterization of the capillary tubes is presented in this paper. The flow behavior is reviewed for straight, helically, and spirally coiled capillary tubes at different operating and geometric conditions by considering various aspects in the tube. This paper summarizes experimental and numerical study on the adiabatic and nonadiabatic straight and coiled capillary tubes at different geometries conditions. The vital information of the range of the tube geometry and operating conditions are discussed, which can be utilized for further studies on the capillary tube. Various methodologies with generalized correlations are indicated. It has been observed that there are even more studies need to do with environmentally friendly refrigerants with various practical aspects in the capillary tube. It would be interesting to find the coiling effect on the design and simulation of the capillary tube. In addition to that more experimental and numerical studies need to explore the nonadiabatic coiled capillary tube. It would be fascinating to study the metastable condition in the capillary tube and set suitable relations to present its effect on the mass flow rate.

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