Numerical Study of Effect of Using Nanofluids Flowing in Simply Supported Pipes on Vibrations Characteristics

2020 ◽  
Vol 38 (1A) ◽  
pp. 43-56
Author(s):  
Kadhum A. Jehhef ◽  
Mohamed A. Siba ◽  
Hayder S. Abdulamir
Keyword(s):  
Natural Frequency ◽  
Volume Fraction ◽  
Numerical Study ◽  
Free Vibrations ◽  
Working Fluid ◽  
Pipeline System ◽  
Pipe Length ◽  
Simply Supported ◽  
General Internal ◽  
Flow Induced Vibrations

In general, internal vibrations within the pipelines caused by fluids being passing through a pipeline system can cause. These pipeline system can damage by the sudden amplified vibrations that weren’t considered at the design of the system, and flow induced vibrations resonate with the pipes natural frequency. Therefore, it is important to predict and identify the pipeline system vibrations during its lifetime. In this study by using MATLAB code as a CFD solver, it studied the forced and free vibrations caused by fluid flows at Reynolds number ranged as 0 < Re < 2500 for laminar flow and ranged as 104 < Re < 105 for turbulent flow. The working fluid has chosen as of (Al2O3, TiO2, SiO2 and water) with different nanoparticle volume fraction of (0 to 2% vol.). These fluids flow in simply supported pipe with different lengths and diameters. The results presented the effect of pipe and fluid parameter upon the fluid critical velocity and fundamental natural frequencies. The results showed that the pipe natural frequency increased with increasing with decreasing the pipe length and diameter. In addition, it showed that the pipe natural frequency decreased when using the different nanoparticle depressed in the water and with increasing the volume fraction.

Processing and Properties of ZA-27 Alloy Metal Matrix Hybrid Composite Reinforced with Nanonitrides

2020 ◽  
Vol 38 (1A) ◽  
pp. 57-64
Author(s):  
Fadhil A. Hashim ◽  
Niveen J. Abdulkader ◽  
Kateralnada F. Hisham
Keyword(s):  
Natural Frequency ◽  
Volume Fraction ◽  
Fluid Flows ◽  
Free Vibrations ◽  
Working Fluid ◽  
Pipeline System ◽  
Pipe Length ◽  
General Internal ◽  
Fluid Parameter ◽  
Flow Induced Vibrations

In general, internal vibrations within the pipelines caused by fluids being passing through a pipeline system can cause. These pipeline system can damage by the sudden amplified vibrations that were not considered at the design of the system, and flow induced vibrations resonate with the pipes natural frequency. Therefore, it is important to predict and identify the pipeline system vibrations during its lifetime. In this study by using MATLAB code as a CFD solver, it studied the forced and free vibrations caused by fluid flows at Reynolds number ranged as 0 < Re < 2500 for laminar flow and ranged as 104 < Re < 105 for turbulent flow. The working fluid has chosen as of (Al2O3, TiO2, SiO2 and water) with different nanoparticle volume fraction of (0 to 2% vol.). These fluids flow in simply supported pipe with different lengths and diameters. The results presented the effect of pipe and fluid parameter upon the fluid critical velocity and fundamental natural frequencies. The results showed that the pipe natural frequency increased with increasing with decreasing the pipe length and diameter. In addition, it showed that the pipe natural frequency decreased when using the different nanoparticle depressed in the water and with increasing the volume fraction.

scholarly journals NUMERICAL STUDY ON THE INHIBITION OF CAVITATION IN PIPING SYSTEMS

2012 ◽  
Vol 19 ◽  
pp. 374-380
Author(s):  
SUN SEOK BYEON ◽  
SANG JUN LEE ◽  
YOUN-JEA KIM
Keyword(s):  
Vapor Pressure ◽  
Volume Fraction ◽  
Numerical Study ◽  
Fluid Velocity ◽  
Working Fluid ◽  
Operating Pressure ◽  
Butterfly Valve ◽  
Saturation Vapor Pressure ◽  
Piping Systems ◽  
Saturation Vapor

Abrupt closing valve in piping systems is sometimes resulted in cavitation due to the occurrence of high pressure difference. The bubbles generating by cavitation influence operating pressure and then those generate shock wave and vibration. These phenomena can consequentially cause to corrosion and erosion. So, the cavitation is the important factor to consider reliability of piping systems and mechanical lifetime. This paper investigated the various inhibition methods of cavitation in piping systems in which butterfly valves are installed. To prevent cavitation occurrence, it is desirable to analyze its characteristics between the upstream and downstream of process valve. Results show that the fluid velocity is fast when a working fluid passed through butterfly valve. The pressure of these areas was not only under saturation vapor pressure of water, but also cavitation was continuously occurred. We confirmed that the effect of existence of inserted orifice and influence to break condition under saturation vapor pressure of water. Results were graphically depicted by pressure distribution, velocity distribution, and vapor volume fraction.

scholarly journals CONVECTIVE HEAT TRANSFER AND POWER SAVING APPLICATION OF SI BASED NANOPARTICLES IN A CIRCULAR PIPE

2020 ◽  
Vol 50 (4) ◽  
pp. 321-327
Author(s):  
Md Insiat Islam Rabby ◽  
Farzad Hossain ◽  
S.A.M. Shafwat Amin ◽  
Tazeen Afrin Mumu ◽  
MD Ashraf Hossain Bhuiyan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Base Fluid ◽  
Volume Fraction ◽  
Numerical Study ◽  
Convective Heat Transfer Coefficient ◽  
Circular Pipe ◽  
Working Fluid ◽  
Pumping Power

A numerical study of laminar forced convection heat transfer for the fully developed region inside a circular pipe filled with Si based nanoparticle is presented for investigating the parameters of heat transfer. Four Si based nanoparticles Si, SiC, SiO2, Si3N4 with 1-5% volume fraction have been mixed with water to prepare nanofluids which is used for working fluid to flow over a circular pipe with 5mm diameter and 700mm length. Heat transfer characteristics and pumping power have been calculated at fully developed region with constant heat flux condition on pipe wall to identify the heat transfer enhancement ratio and pumping power reduction ratio among base fluid water and each nanofluids. It is worth mentioning that utilizing SiC nanoparticle shows not only the highest increment of Nusselt number and convective heat transfer coefficient but also the highest decrement of pumping power requirement and FOM in comparison to the base fluid.

Determination of Parabolic Trough Solar Collector Efficiency Using Nanofluid: A Comprehensive Numerical Study

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Hamidreza Khakrah ◽  
Amir Shamloo ◽  
Siamak Kazemzadeh Hannani
Keyword(s):  
Renewable Energy ◽  
Solar Collector ◽  
Volume Fraction ◽  
Numerical Study ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Parabolic Trough ◽  
Metallic Nanoparticle ◽  
Velocity Magnitude ◽  
Parabolic Trough Solar Collector

Due to significant reduction in fossil fuel sources, several researches have been conducted recently to explore modern sources of renewable energy. One of the major fields in the category of renewable energy harnessing devices is parabolic trough solar collector (PTC). Several parameters have effect on the overall efficiency of the PTCs. As the effect of these parameters is coupled to each other, a comprehensive investigation is necessary. In the present study, a numerical analysis is performed to examine the efficiency of PTCs via variation of several governing parameters (e.g., wind velocity magnitude, nanoparticles volume fraction, inlet temperature, and reflector's orientation). A detailed set of absorber, reflector, and protection glass in addition to the surrounding environment is modeled to capture sufficiently accurate data. The working fluid is assumed to be nanofluid to inspect the advantage of metallic nanoparticle addition to the base fluid. The Monte Carlo radiation tracing method is utilized to calculate the solar gain on the absorber tube. According to the obtained results, the efficiencies are reduced by 1–3% by rotating the reflector by 30 deg relative to wind direction. Moreover, 14.3% and 12.4% efficiency enhancement is obtained by addition of 5% volume fraction of Al2O3 to the base synthetic oil for horizontal and rotated reflectors, respectively.

scholarly journals Numerical Study of MHD Natural Convection in Trapezoidal Enclosure Filled With (50%MgO-50%Ag/Water) Hybrid Nanofluid: Heated Sinusoidal from Below

2021 ◽  
Vol 39 (4) ◽  
pp. 1271-1279
Author(s):  
Mohammed Azeez Alomari ◽  
Khaled Al-Farhany ◽  
Alaa Liaq Hashem ◽  
Mohamed F. Al-Dawody ◽  
Fares Redouane ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Hartmann Number ◽  
Volume Fraction ◽  
Numerical Study ◽  
Working Fluid ◽  
Hybrid Nanofluid ◽  
Nusselt Numbers ◽  
Stream Functions ◽  
Trapezoidal Enclosure ◽  
Good Agreement

Numerical simulation of MHD free convection in a two-dimensional trapezoidal cavity of a hybrid nanofluid has been carried out in this research. The cavity is heated sinusoidal from the bottom wall, and the inclined walls are cooled while the top wall is isolated. The hybrid nanofluid (MgO-Ag/water) has been used as a working fluid. The numerical simulation has been validated with past papers and met a good agreement. The considered parameters are a range of Rayleigh number (Ra= 103 to 106), Hartmann number (Ha= 0 to 60) and volume fraction (f= 0 to 0.02). The results are presented as isotherms, stream functions, local and average Nusselt numbers, from which it is observed that the strength of the stream functions and isotherms increases with the increase of the Ra and ϕ while the increase in Hartmann number reduce the circulation of the flow and increases the isotherms strength. Also, the Nusselt number is increases with Ra and ϕ while it decreases with Ha.

scholarly journals Free Vibrations of Nanoscale Beam Under Two-Temperature Green and Naghdi Model

2018 ◽  
Vol 23 (No 3, September 2018) ◽  
pp. 289-293 ◽  
Author(s):  
Ibrahim A. Abbas
Keyword(s):  
Free Vibration ◽  
Strain Rate ◽  
Frequency Shift ◽  
Natural Frequency ◽  
Free Vibrations ◽  
Temperature Model ◽  
Thermoelastic Damping ◽  
Simply Supported ◽  
Two Temperature

The influence of the coupling between strain rate and temperature becomes domineering in the nanoscale beam. In this work, the free vibration of nanoscale beam resonators is analysed using Green and Naghdis theorem under the two-temperature model (2TGNIII). The influence of two-temperature parameters in a nanoscale beam is studied for beams under simply supported conditions. Exact expressions for frequency shift and the thermoelastic damping have been derived in the resonator, and calculation outcomes have been presented graphically with respect to frequency shift, natural frequency, and thermoelastic damping. The scale of length and thickness for a nanobeam equal to 15 × 10−9 m and equal to 1.3 × 10−12 s for time.

Numerical Study on Effect of Volume Fraction of Nanoparticles on Rayleigh-Bernard Convection in Different Enclosures

2014 ◽  
Vol 592-594 ◽  
pp. 945-950 ◽  
Author(s):  
S. Senthil Kumar ◽  
S. Karthikeyan
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Volume Fraction ◽  
Numerical Study ◽  
Flow Characteristics ◽  
Boussinesq Approximation ◽  
Working Fluid ◽  
Volume Fractions ◽  
Aspect Ratios ◽  
Fluid Flow Characteristics

Numerical investigations of Rayleigh-Bernard convection in enclosures of different modified bottom and top surfaces filled with Au-Water Nanofluid with different volume fractions are presented. This paper describes a numerical predication of heat transfer and fluid flow characteristics inside enclosures bounded by modified bottom and top surfaces and two periodic straight vertical walls. Simulations are carried out for a Rayleigh number of 6×104 and two aspect ratios (0.25 & 0.5) with working fluid as Au-Water Nanofluid and The same analyses are performed with the Nanofluid having Au nanoparticles of same size and different volume fraction of φ = 5%, 10%, 15% and 20 % in order to see the effect of Nanofluid volume fraction on heat transfer. The Boussinesq approximation is used in order to take density change effect in the governing equations. The study investigates the effect of the nanoparticles volume fraction, and the aspect ratio on the heat transfer. The results are presented in terms of isotherms, streamlines local and average surface Nusselt numbers. Results show that the flow and isotherms are affected by the geometry shape and by the presence of nanoparticles with different volume fractions. It is also shown that for a fixed value of aspect ratio, the convective heat transfer is decreased for the increase in volume fraction of Nanofluid.

Thermal Performance of an Al2O3–Water Nanofluid Pulsating Heat Pipe

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Hamid Reza Seyf ◽  
Sejung Kim ◽  
Yuwen Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Pipe ◽  
Volume Fraction ◽  
Numerical Study ◽  
Pure Water ◽  
Working Fluid ◽  
Pulsating Heat Pipe ◽  
Liquid Slug ◽  
Temperature And Pressure ◽  
Vapor Temperature

A numerical study is performed to investigate the effects of nanofluids on the heat transfer performance of a pulsating heat pipe (PHP). Pure water is employed as the base fluid while Al2O3 with two different particle sizes, 38.4 and 47 nm, is used as nanoparticle. Different parameters including displacement of liquid slug, vapor temperature and pressure, liquid slug temperature distribution, as well as sensible and latent heat transfer in evaporator and condenser are calculated numerically and compared with the ones for pure water as working fluid. The results show that nanofluid has significant effect on heat transfer enhancement of the system and with increasing volume fraction and decreasing particles diameter the enhancement intensifies.

USAGE OF A DIATOMITE-CONTAINING NANOFLUID AS THE WORKING FLUID IN A WICKLESS LOOP HEAT PIPE: EXPERIMENTAL AND NUMERICAL STUDY

2018 ◽  
Vol 49 (17) ◽  
pp. 1721-1744 ◽  
Author(s):  
Adnan Sözen ◽  
Erdem Çiftçi ◽  
Selçuk Keçel ◽  
Metin Gürü ◽  
Halil Ibrahim Variyenli ◽  
...  
Keyword(s):  
Heat Pipe ◽  
Numerical Study ◽  
Working Fluid ◽  
Loop Heat Pipe

scholarly journals Numerical Study on an Interface Compression Method for the Volume of Fluid Approach

Fluids ◽  
2021 ◽  
Vol 6 (2) ◽  
pp. 80
Author(s):  
Yuria Okagaki ◽  
Taisuke Yonomoto ◽  
Masahiro Ishigaki ◽  
Yoshiyasu Hirose
Keyword(s):  
Linear Theory ◽  
Volume Fraction ◽  
Numerical Study ◽  
Volume Of Fluid ◽  
Interfacial Wave ◽  
Validation Process ◽  
Two Phase ◽  
Numerical Diffusion ◽  
Mesh Resolution ◽  
Water Reactors

Many thermohydraulic issues about the safety of light water reactors are related to complicated two-phase flow phenomena. In these phenomena, computational fluid dynamics (CFD) analysis using the volume of fluid (VOF) method causes numerical diffusion generated by the first-order upwind scheme used in the convection term of the volume fraction equation. Thus, in this study, we focused on an interface compression (IC) method for such a VOF approach; this technique prevents numerical diffusion issues and maintains boundedness and conservation with negative diffusion. First, on a sufficiently high mesh resolution and without the IC method, the validation process was considered by comparing the amplitude growth of the interfacial wave between a two-dimensional gas sheet and a quiescent liquid using the linear theory. The disturbance growth rates were consistent with the linear theory, and the validation process was considered appropriate. Then, this validation process confirmed the effects of the IC method on numerical diffusion, and we derived the optimum value of the IC coefficient, which is the parameter that controls the numerical diffusion.

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