scholarly journals Analysis of Void Fraction Distribution and Departure from Nucleate Boiling in Single Subchannel and Bundle Geometries Using Subchannel, System, and Computational Fluid Dynamics Codes

2012 ◽  
Vol 2012 ◽  
pp. 1-20 ◽  
Author(s):  
Taewan Kim ◽  
Victor Petrov ◽  
Annalisa Manera ◽  
Simon Lo
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Void Fraction ◽  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Nucleate Boiling ◽  
Significant Discrepancy ◽  
Computational Fluid Dynamic Code ◽  
Fraction Distribution ◽  
Paul Scherrer

In order to assess the accuracy and validity of subchannel, system, and computational fluid dynamics codes, the Paul Scherrer Institut has participated in the OECD/NRC PSBT benchmark with the thermal-hydraulic system code TRACE5.0 developed by US NRC, the subchannel code FLICA4 developed by CEA, and the computational fluid dynamic code STAR-CD developed by CD-adapco. The PSBT benchmark consists of a series of void distribution exercises and departure from nucleate boiling exercises. The results reveal that the prediction by the subchannel code FLICA4 agrees with the experimental data reasonably well in both steady-state and transient conditions. The analyses of single-subchannel experiments by means of the computational fluid dynamic code STAR-CD with the CD-adapco boiling model indicate that the prediction of the void fraction has no significant discrepancy from the experiments. The analyses with TRACE point out the necessity to perform additional assessment of the subcooled boiling model and bulk condensation model of TRACE.

scholarly journals Increasing the speed of computational fluid dynamics procedure for minimization the nitrogen oxide polution from the premixed atmospheric gas burner

2017 ◽  
Vol 21 (2) ◽  
pp. 1031-1041
Author(s):  
Vasko Fotev ◽  
Miroljub Adzic ◽  
Aleksandar Milivojevic
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Nitrogen Oxide ◽  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Working Time ◽  
Innovative Method ◽  
Gas Burner ◽  
Dynamic Software ◽  
Computational Fluid Dynamic Software

This article presents innovative method for increasing the speed of procedure which includes complex computational fluid dynamic calculations for finding the distance between flame openings of atmospheric gas burner that lead to minimal NO pollution. The method is based on standard features included in commercial computational fluid dynamic software and shortens computer working time roughly seven times in this particular case.

scholarly journals Analisis Distribusi Temperatur dan Aliran Fluida pada Proses Pengeringan Butiran Teh Bentuk Silinder Di Dalam Fluidized Bed Dryer Menggunakan Computational Fluid Dynamic (CFD)

ROTASI ◽  
2019 ◽  
Vol 20 (4) ◽  
pp. 237
Author(s):  
MSK Tony Suryo Utomo ◽  
Eflita Yohana ◽  
Mauli Astuti Khoiriyah
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fluidized Bed ◽  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Fluidized Bed Dryer ◽  
Computational Fluid Dynamics Cfd

Pengeringan merupakan proses perpindahan panas dan uap air secara simultan yang memerlukan energi panas untuk menguapkan kandungan air dari bahan yang akan dikeringkan. Penelitian ini dilakukan dengan cara simulasi. Produk yang dipilih untuk simulasi ini yaitu teh. Simulasi numerik perpindahan massa pada teh dilakukan dengan menempatkan material teh pada domain komputasi sebuah aliran eksternal. Penelitian ini bertujuan untuk menganalisis distribusi temperatur pada partikel teh dengan menggunakan Computational Fluid Dynamics (CFD) dan menganalisis pengaruh variasi kecepatan inlet dan temperatur inlet terhadap waktu pengeringan sehingga diperoleh metode pengeringan yang paling optimum pada pengeringan teh. Penurunan massa pada teh dihitung secara analitik dengan menggunakan persamaan laju penurunan massa. Teh dimodelkan dengan bentuk menyerupai silinder setelah dilakukan pelayuan untuk kemudian dikeringkan. Kecepatan masuk aliran udara dan temperatur masuk divariasikan sesuai dengan batas kecepatan minimum dan maksimum fluidisasi dan temperatur pengeringan teh untuk fluidized bed dryer. Waktu yang digunakan untuk menurunkan kadar air hingga 3% berdasarkan temperatur pada kecepatan 1,6 m/s secara berurutan adalah 354 s (880C), 300 s (930C), dan 256 s (980C). Sementara pada kecepatan 2,6 m/s waktu yag dibutuhkan adalah 277 s (880C), 234 s (930C), dan 200 s (980C) serta untuk kecepatan 3,6 m/s berturut-turut 235 s (880C), 199 s (930C), dan 169 s (980C). Untuk pengeringan teh lebih optimal dilakukan dengan menaikkan kececepatan masuk aliran fluida dibandingkan dengan menaikkan temperatur.

scholarly journals On the computational fluid dynamics of PEM fuel cells (PEMFCs): an investigation on mesh independence analysis

RSC Advances ◽  
2017 ◽  
Vol 7 (52) ◽  
pp. 32893-32902 ◽  
Author(s):  
H. Kazemi Esfeh ◽  
A. Azarafza ◽  
M. K. A. Hamid
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fuel Cells ◽  
Dynamic Modeling ◽  
Polarization Curve ◽  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Pem Fuel Cells ◽  
Mesh Independence ◽  
Computational Fluid Dynamic Modeling

The results clearly show that the polarization curve is not enough to check the independency in grid in PEMFC computational fluid dynamic modeling.

PENINGKATAN KUALITAS MONITORING PROSES PRODUKSI ALUMINIUM FOIL: EVALUASI KINERJA FURNACE DENGAN COMPUTATIONAL FLUID DYNAMICS DAN KUALITAS PROSES DENGAN STATISTICAL PROCESS CONTROL (SPC - EWMA, CUSUM)

2017 ◽  
Vol 8 (2) ◽  
pp. 449
Author(s):  
Muhamad Fasial ◽  
Wiratno Argo Asmoro ◽  
Ruri Agung Wahyuono ◽  
Edy Sugiantoro
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Process Control ◽  
Statistical Process Control ◽  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Settling Time ◽  
Aluminium Foil ◽  
Annealing Furnace ◽  
Statistical Process

Artikel ini mempresentasikan evaluasi performansi tungku anil (annealing furnace) pada produksi aluminium foil dikarenakan mayoritas cacat produk bersumber pada proses anil. Selain itu, pengendalian proses statistik menggunakan skema EWMA dan CUSUM telah diimplementasikan untuk mengevaluasi kualitas proses secara keseluruhan pada produksi aluminium foil. Studi berbasis Computational Fluid Dynamic (CFD) telah dilakukan untuk mengevaluasi distribusi temperatur dan aliran udara di dalam tungku anil. Tungku anil dengan model inlet-outlet udara panas dari samping yang diinvestigasi pada artikel ini menunjukkan distribusi temperatur yang homogen, tetapi terdapat beberapa volume dimana aliran udara mengalami saturasi dan dapat menyebabkan penjebakan uap minyak pendingin pada proses sebelumnya (rolling). Berdasarkan respon pengendalian temperatur (PID), nilai gain proporsioal perlu diperbesar agar settling time menjadi lebih pendek. Waktu konduksi aluminium yag berbeda berdasarkan data eksperimen dan perhitungan teoretis menunjukkan adanya panas yang hilang berlebih selama proses anil, sehingga perbaikan sistem isolasi tungku anil diperlukan. Hasil evaluasi kualitas proses menunjukkan bahwa grafik kendali CUSUM mampu mendeteksi perubahan proses skala kecil dan besar, namun metode ini membutuhkan inspeksi lebih lanjut  apakah data proses keluar dalam batas kendali atau tidak. Grafik kendali EWMA (faktor pembobotan l = 0,6) mampu mendeteksi cacat proses yang lebih banyak (terverifikasi dengan hasil inspeksi) dari grafik kendali CUSUM, sehingga skema EWMA lebih cocok digunakan untuk proses produksi aluminium foil dengan sistem batch.

scholarly journals Continuous flow synthesis of a pharmaceutical intermediate: a computational fluid dynamics approach

2019 ◽  
Vol 4 (3) ◽  
pp. 634-642 ◽  
Author(s):  
Cameron T. Armstrong ◽  
Cailean Q. Pritchard ◽  
Daniel W. Cook ◽  
Mariam Ibrahim ◽  
Bimbisar K. Desai ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Computational Fluid Dynamic ◽  
Continuous Flow ◽  
Fluid Dynamic ◽  
Flow Synthesis ◽  
Reaction Performance ◽  
Experimental Approaches

Computational fluid dynamic and experimental approaches have been compared in the prediction of reaction performance in the preparation of a pharmaceutical intermediate.

scholarly journals MODEL ANALITIK SLOSHING TANGKI- MUAT PADA OLAH GERAK KAPAL FLOATING LIQUEFIED NATURAL GAS (FLNG) = ANALITICAL MODEL OF SLOSHING IN STORAGE TANK ON FLOATING LIQUEFIED NATURAL GAS (FLNG) SHIP MOTION

2015 ◽  
Vol 9 (1) ◽  
pp. 1-12
Author(s):  
Luhut Tumpal Parulian Sinaga
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Natural Gas ◽  
Numerical Simulations ◽  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Model Testing ◽  
Liquefied Natural Gas ◽  
Ship Motion ◽  
Ocean Engineering

Studies on the effect of sloshing motion and heave coupling picth after receiving an external force wage varying wave energy and angular variation headings. This study will conduct a study of physical model testing with mooring configuration and MAT-LAB program of mathematical models free floating barge matika mechanism through numerical simulations and computational fluid dynamic (CFD). This riset aims to observe and explain the effect of sloshing on ship motions and the interaction with the research methodology systematically carried through the calculation/numerical simulations (Mathematics and Computational Fluid Dynamics Laboratory), and the physical scale model testing (at Maneuvering and Ocean Engineering Basin).The results of the study through experiments and numerical phenomenon suggests that the effect of sloshing on the effect of ship motion can be well understood. Pressure due to the wave heading angle of 90 degrees gives a higher impact pressure. Style sloshing is not directly proportional to the amplitude of excitation. AbstrakKajian pengaruh dari sloshing terhadap gerakan kopel heave dan picth setelah menerima gaya external berupa energi gelombang yang bervariasi dan variasi sudut heading. Kajian ini akan melakukan kajian pengujian model fisik dengan konfigurasi tambat yang dan program matematik MAT-LAB dari model matematika free floating barge mechanism serta melalui simulasi numerik computational fluid dynamic (CFD).Penelitian bertujuan mengamati dan menjelaskan pengaruh sloshing terhadap gerakan kapal dan interaksi tersebut secara sistimatis dengan metodologi penelitian yang dilakukan melalui perhitungan/ simulasi numerik (mathematics laboratory dan computational fluid dynamics), dan pengujian model skala fisik (di maneuvering and ocean engineering basin). Konfigurasi geometri model yang disimulasikan dan diuji adalah tipe FLNG dengan tangki berisi muatan cair yang memungkinkan terdapat permukaan bebas.Hasil kajian melalui eksperimen dan numerik menunjukkan bahwa efek fenomena sloshing terhadap pengaruh gerakan kapal dapat diketahui dengan baik. Pada sudut heading 900 terdapat gerakan yang tidak jelas sehingga perlu adanya investigasi lebih lanjut. Persamaan nonlinier aliran sloshing sangat diperlukan untuk dapat menghitung besaran gerakan kapal. Tekanan akibat gelombang pada sudut heading 900 memberikan dampak tekanan yang lebih tinggi. Gaya sloshing tidak berbanding lurus dengan amplitudo eksitasi. Oleh karena itu, gerakan kapal ditambah dengan sloshing tidak bervariasi secara linier terhadap amplitudo gelombang. 

scholarly journals ANALISIS AERODINAMIKA PADA BODI MOBIL HEMAT ENERGI LINTANG SAMUDRA MENGGUNAKAN METODE COMPUTATIONAL FLUID DYNAMICS

2020 ◽  
Vol 16 (1) ◽  
Author(s):  
Bagus Wahyu Prastyo ◽  
Imam Syafa’at ◽  
Muhammad Dzulfikar
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Drag Coefficient ◽  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Lift Coefficient

Aerodinamika kendaraan merupakan bentuk pergerakan aliran udara yang memberi pengaruh atau menyebabkan gaya kepada benda saat bergerak dengan kecepatan tertentu. Ada beberapa cara untuk mengetahui bentuk aerodinamika kendaraan. Pertama yaitu melakukan eksperimen dengan memasukkan kendaraan pada terowongan angin. Cara kedua yaitu menggunakan software CFD (Computational fluid dynamic). Dengan metode CFD peneliti dapat membuat berbagai bentuk desain tanpa mengeluarkan biaya tambahan. Penelitian ini bertujuan untuk mengetahui aerodinamika serta nilai Drag coefficient (CD) dan Lift coefficient (CL) pada bodi mobil Lintang Samudra. Simulasi dilakukan pada 4 kecepatan aliran udara yaitu 40, 50,60 dan 70 km/h. Simulasi menggunakan model turbulensi k-ɛ dengan intensitas 5%, model tersebut dipilih karena memiliki tingkat error terkecil terhadap validasi dari jurnal simulasi Bammidi dan Murty (2014) sebesar 0,13 %. Didapatkan hasil bodi Lintang Samudra 1 memiliki nilai CD = 0,07598 - 0,07025 dan CL=(-0,00800) – (-0,00837) Pada bodi Lintang Samudra 2 memiliki nilai CD = 0,072451 - 0,067020 dan CL = 0,001395 – 0,000949. Terdapat perbedaan bentuk aliran fluida pada bodi Lintang Samudra 1dan bodi Lintang Samudra 2. Jadi bodi kedua lebih aerodinamis dari bodi pertama. Kata kunci: aerodinamika, bodi, CFD, drag, lift.

scholarly journals Advances in cubicle design using computational fluid dynamics as a design tool

1998 ◽  
Vol 32 (2) ◽  
pp. 117-127 ◽  
Author(s):  
G. Curry ◽  
H. C. Hughes ◽  
D. Loseby ◽  
S. Reynolds
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Animal Models ◽  
Computational Fluid Dynamic ◽  
Fluid Dynamic ◽  
Design Tool ◽  
Optimal Configuration ◽  
Low Level ◽  
Containment System

As part of a recent animal facility refurbishment, a cubicle containment system was designed to increase the amount of experimental space and also provide containment facilities to support the holding and use of specialized animal models. In order to achieve this, a series of computational fluid dynamic (CFD) studies was undertaken to evaluate the effects of different airflows and in order to optimize ventilation, a variety of exhaust/supply arrangements and animal loads was employed. These studies showed that air delivered via two, opposed, low level ducts, at a rate of 20 air changes per hour and exhausted high in the cubicle above the rack, was the optimal configuration resulting in minimal turbulence, stagnation and entrainment.

Air Ingress Analysis: Computational Fluid Dynamics Models

2010 ◽  
Author(s):  
Chang H. Oh ◽  
Eung S. Kim
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Temperature ◽  
Fluid Dynamic ◽  
Department Of Energy ◽  
Validation Data ◽  
The Core ◽  
Air Ingress ◽  
Dynamics Models ◽  
Very High

Idaho National Laboratory (INL), under the auspices of the U.S. Department of Energy (DOE), is performing research and development that focuses on key phenomena important during potential scenarios that may occur in very high temperature reactors (VHTRs). Phenomena identification and ranking studies to date have ranked an air ingress event, following on the heels of a VHTR depressurization, as important with regard to core safety. Consequently, the development of advanced air-ingress-related models and verification and validation data are a very high priority. Following a loss of coolant and system depressurization incident, air will enter the core of the High Temperature Gas Cooled Reactor through the break, possibly causing oxidation of the core and reflector graphite structure. Simple core and plant models indicate that, under certain circumstances, the oxidation may proceed at an elevated rate with additional heat generated from the oxidation reaction itself. Under postulated conditions of fluid flow and temperature, excessive degradation of lower plenum graphite can lead to a loss of structural support. Excessive oxidation of core graphite can also lead to a release of fission products into the confinement, which could be detrimental to reactor safety. Computational fluid dynamics models developed in this study will improve our understanding of this phenomenon. This paper presents two-dimensional (2-D) and three-dimensional (3-D) computational fluid dynamic (CFD) results for the quantitative assessment of the air ingress phenomena. A portion of the results from density-driven stratified flow in the inlet pipe will be compared with the experimental results.

scholarly journals Three-dimensional multiphase flow computational fluid dynamics models for proton exchange membrane fuel cell: A theoretical development

2017 ◽  
Vol 9 (1) ◽  
pp. 3-25 ◽  
Author(s):  
Jean-Paul Kone ◽  
Xinyu Zhang ◽  
Yuying Yan ◽  
Guilin Hu ◽  
Goodarz Ahmadi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fuel Cell ◽  
Multiphase Flow ◽  
Proton Exchange Membrane ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Proton Exchange ◽  
Dynamics Models ◽  
Exchange Membrane

A review of published three-dimensional, computational fluid dynamics models for proton exchange membrane fuel cells that accounts for multiphase flow is presented. The models can be categorized as models for transport phenomena, geometry or operating condition effects, and thermal effects. The influences of heat and water management on the fuel cell performance have been repeatedly addressed, and these still remain two central issues in proton exchange membrane fuel cell technology. The strengths and weaknesses of the models, the modelling assumptions, and the model validation are discussed. The salient numerical features of the models are examined, and an overview of the most commonly used computational fluid dynamic codes for the numerical modelling of proton exchange membrane fuel cells is given. Comprehensive three-dimensional multiphase flow computational fluid dynamic models accounting for the major transport phenomena inside a complete cell have been developed. However, it has been noted that more research is required to develop models that include among other things, the detailed composition and structure of the catalyst layers, the effects of water droplets movement in the gas flow channels, the consideration of phase change in both the anode and the cathode sides of the fuel cell, and dissolved water transport.

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