Effect of Dual Frequency Ultrasound on the Bubble Formation in a Capillary Tube

2017 ◽  
Vol 139 (2) ◽  
Author(s):  
Benwei Fu ◽  
Nannan Zhao ◽  
Guoyou Wang ◽  
Hongbin Ma
Keyword(s):  
Bubble Growth ◽  
High Speed ◽  
Capillary Tube ◽  
Bubble Formation ◽  
Single Frequency ◽  
Quartz Tube ◽  
Outer Diameter ◽  
Dual Frequency ◽  
Heating Section ◽  
Frequency Ultrasound

A visual experimental investigation was conducted to determine the effect of dual frequency ultrasound on the bubble formation and growth in a capillary quartz tube. Two piezoelectric ceramics were used in this experiment. They were made of Pb-based lanthanum-doped zirconate titanates (PLZTs). The PLZTs were placed on a quartz tube with an inner diameter of 2 mm and an outer diameter of 3 mm. The capillary tube was vacuumed first and then charged with water using a filling ratio of 70%. The ultrasonic sound was applied to the heating section of a capillary tube. The bubble formation and growth were recorded by a high speed camera. As shown in figures, when the ultrasound with a single frequency of either 154 kHz or 474 kHz was applied, only one bubble was generated. When the dual frequencies of 154 kHz and 474 kHz were applied, more bubbles were generated. The speed of the bubble growth with dual frequency ultrasound was much higher than that with a single frequency. When a dual frequency ultrasound (154 kHz and 474 kHz) was used, the nucleation sites for bubble formation were significantly increased and the bubble growth rate enhanced.

Effect of Dual Frequency Ultrasound on the Bubble Formation in a Capillary Tube

2016 ◽  
Author(s):  
Benwei Fu ◽  
Nannan Zhao ◽  
Guoyou Wang ◽  
Hongbin Ma
Keyword(s):  
Bubble Growth ◽  
High Speed ◽  
Capillary Tube ◽  
Bubble Formation ◽  
High Speed Camera ◽  
Dual Frequency ◽  
Heating Section ◽  
Nucleation Sites ◽  
Ultrasonic Sound ◽  
Frequency Ultrasound

A visual experimental was conducted to determine the effect of dual frequency ultrasound on the bubble formation and growth in a capillary quartz tube. The ultrasonic sound was applied to the heating section of a capillary tube by using electrically-controlled piezoelectric ceramics made of Pb-based lanthanum-doped zirconate titanates (PLZTs). The bubble formation and growth were recorded by a high speed camera. Experimental results show that the bubble formation and growth depend on PLZT frequency. When a dual frequency ultrasound (154 kHz and 474 kHz) was used, the nucleation sites for bubble formation were significantly increased and the bubble growth rate enhanced.

Regeneration of Granular Activated Carbon Using Dual-Frequency Ultrasound

2012 ◽  
Vol 616-618 ◽  
pp. 1707-1710
Author(s):  
Jiong Yuan Lu ◽  
San Fan Wang ◽  
Jin Feng Zhu
Keyword(s):  
Activated Carbon ◽  
Granular Activated Carbon ◽  
Experimental Results ◽  
Single Frequency ◽  
Dual Frequency ◽  
Thermal Regeneration ◽  
Regeneration Efficiency ◽  
The Individual ◽  
Better Than ◽  
Frequency Ultrasound

The saturate granular activated carbon(GAC) which adsorbed Ni2+ is regenerated using dual-frequency ultrasound. The individual frequency is 45KHz, 80KHz and 100KHz respectively. The experimental results show that the regeneration efficiency using dual-frequency ultrasound is better than that using single- frequency ultrasound under the same experimental condition. When the two ultrasound’s frequency is 45KHz, the regeneration efficiency is 81.03%, comparing single- frequency ultrasound it increase by 40% and it is the best in six group dual-frequency ultrasound. In conclusion, the dual-frequency ultrasound regeneration showed a possibility as an alternative to chemical and thermal regeneration of GAC.

Visualization of Heat Transfer Characteristics of 1EHT and Smooth Surface Tubes

2021 ◽  
Author(s):  
Humberto Santos ◽  
Ailson Alves ◽  
David Kukulka ◽  
Rick Smith ◽  
Wei Li
Keyword(s):  
Heat Transfer ◽  
Particle Velocity ◽  
High Speed ◽  
High Efficiency ◽  
Bubble Formation ◽  
Industrial Applications ◽  
Smooth Tube ◽  
Outer Diameter ◽  
Average Particle ◽  
Enhanced Heat Transfer

Abstract High efficiency heat transfer tubes play a major role in industrial applications due to its benefits in recovering more energy, smaller footprint and lower operational costs. Given the importance of enhanced heat transfer tubes, an experimental investigation was carried out to compare the performance of the Vipertex 1EHT tube with an equivalent smooth tube using Particle Image Velocimetry (PIV). For the experimental setup a Dantec Dynamics PIV system was considered, and both tubes used had an outer diameter of 19.05 mm and inner diameter of 17.09 mm. Heat transfer experiments were conducted at 100% of the heater power capacity, i.e. 750 W, and observations were made in terms of boiling visualization, particle velocity vector field, and seeding particle velocity. The results obtained from the visualization showed higher density of bubble formation on the surface of 1EHT tube compared to the smooth tube, as well as a more frequent formation of bubbles. Moreover, the high-speed camera films recorded for comparison between smooth and enhanced tubes, showed that the dimples provided nucleation sites. Additionally, the average particle velocity for the 1EHT tube was 0.300 m.s−1 and for the smooth tube it was only 0.230 m.s−1, as a result of the higher heat transfer of the enhanced tube. These results suggest that the 1EHT tube performs better in boiling heat transfer application, which can be attributed to the enhanced heat transfer area produced by the series of dimples/protrusions and petals distributed over its surface.

Active Control of Fluid Pressure Pulsation in Hydraulic Pipe System by Bilateral-Overflow of Piezoelectric Direct-Drive Slide Valve

2014 ◽  
Vol 136 (3) ◽  
Author(s):  
Guan Changbin ◽  
Jiao Zongxia ◽  
Wu Shuai ◽  
Shang Yaoxing ◽  
Zheng Fanggang
Keyword(s):  
Active Control ◽  
High Speed ◽  
Pressure Pulsation ◽  
Control Method ◽  
Fluid Pressure ◽  
Slide Valve ◽  
Single Frequency ◽  
Direct Drive ◽  
Dual Frequency ◽  
Pipe System

In this paper, a novel active control of fluid pressure pulsation (ACFPP) is proposed, which meets the need of the high-pressure and high-speed hydraulic pipe system. A piezoelectric direct-drive slide valve (PDDSV) is designed and used as the active vibration absorber. Two ports of the PDDSV both connect to a bypass near the pump outlet and the other two ports both connect to the oil tank. By the bilateral-overflow through the shoulder of the PDDSV, the overflow wave generated in one cycle of spool motion can cancel two cycles of flow ripple. An adaptive-optimum control method based on the rotate-vector optimization method (RVOM) is adopted to adjust the control parameters in order to minimize the amplitude of the pressure pulsation. The biggest advantage of the proposed ACFPP is that it can eliminate the pressure pulsation when PDDSV only works at half of the pressure pulsation's frequency. The simulation and experimentation both verify the proposed ACFPP. By the proposed ACFPP, the suppression for the single-frequency component and dual-frequency components of the pressure pulsation have been both realized.

Visual Observations of Chamber Volume Effect on Ebullience From Submerged Orifice Plates

2016 ◽  
Author(s):  
Sanjivan Manoharan ◽  
Milind A. Jog ◽  
Raj M. Manglik
Keyword(s):  
Surface Tension ◽  
Bubble Growth ◽  
High Speed ◽  
Capillary Tube ◽  
Volume Effect ◽  
Orifice Plate ◽  
Orifice Diameter ◽  
Chamber Volume ◽  
Acrylic Glass ◽  
Liquid Pools

Effect of chamber volume upstream of the orifice on ebullience from orifice plates is studied experimentally in this paper. Bubble growth from orifice plates submerged in liquid pools is captured using high speed videography. The orifice plate substrate is acrylic glass and 11 different orifice diameters (diameter range: 0.610< D0< 2.261mm) are utilized. In addition to water, ethanol-water binary mixture with surface tension of 54 mN/m is used to examine the interplay between surface tension and chamber volume effects on bubble characteristics. For an acrylic glass orifice plate with a fixed chamber volume, above a certain transition orifice diameter, the bubbles from the orifice plate are of the same size and shape as those from a capillary tube orifice. However, below this diameter, the bubbles from the orifice plate show significantly different characteristics due to the chamber volume effect. The bubbles are more spherical in shape with the apex being sharper and more pointed. The bubbles also tend to sit closer to the plate due to their abnormally large size while the growth times are much shorter. These differences are highlighted by comparing photographs of bubble growth with and without the chamber volume effect. Additionally, for the medium chamber region, an empirical correlation was proposed to predict bubble departure diameters to within ±15 %. For a fixed chamber volume, variation in surface tension showed no change in the transition orifice diameter.

Wetting and Capillarity Effects On Bubble Formation From Orifice Plates Submerged in Pools of Water

2021 ◽  
Author(s):  
Sanjivan Manoharan ◽  
Raj M. Manglik ◽  
Milind A. Jog
Keyword(s):  
Contact Angle ◽  
Bubble Growth ◽  
High Speed ◽  
Bubble Formation ◽  
Minimum Energy ◽  
Hydrophobic Surface ◽  
Contact Angles ◽  
Orifice Diameter ◽  
Capillary Length ◽  
Critical Contact

Abstract An experimental study of bubble growth from submerged orifice plates in pools of water is carried out to scale and correlate the effects of surface wettability and orifice diameter D0 on ebullience. Measurements of bubble growth on surfaces with nine different contact angles (38° ≤ θ ≤ 128°) with varying air flow rates (1 to 300 ml/min) were made using high speed videography and image processing. In the static or constant-volume regime, below a critical contact angle θc, the bubble base remains attached to the orifice and the equivalent departure diameter Db is independent of contact angle θ. On the other hand, above the critical contact angle, the bubble base spreads on the surface resulting in larger Db. For θ &gt; θc, Db is strongly dependent on θ and increases with it. Using minimum energy method, it is shown that the wettability effects can be scaled and correlated by a modified capillary length, defined as a function of the Laplace length and contact angle. The proposed correlation provides predictions of Db that agree with experimental data of this study as well as those available in the literature to within ±15 %. Moreover, for a hydrophobic surface when D0 &gt; twice the modified capillary length, the bubble grows inside the orifice; for a hydrophilic surface this scales with twice the capillary length and effect of θ is not seen.

Dual-Frequency Ultrasonic Desorption of Pb2+ from Coconut Shell Activated Carbon

2013 ◽  
Vol 777 ◽  
pp. 38-42
Author(s):  
Jian Zhou ◽  
San Fan Wang
Keyword(s):  
Activated Carbon ◽  
Metal Ion ◽  
Coconut Shell ◽  
Single Frequency ◽  
Dual Frequency ◽  
Cavitation Effect ◽  
Desorption Efficiency ◽  
The Stability ◽  
Coconut Shell Activated Carbon ◽  
Frequency Ultrasound

Desorption experiments of coconut shell activated carbon (CSAC) saturated with Pb2+had been conducted in presence of dual-frequency and single-frequency (30 kHz,500 kHz,1200 kHz) ultrasound. The desorption efficiency was better at dual-frequency ultrasound than at single-frequency ultrasound. The best of desorption efficiency of Pb2+was 65.5% at 500×500 kHz. The desorption efficiency of Pb2+increased by increasing temperature, but when the temperature was more than 50°C, the desorption efficiency decreased initially. The stability of CSAC was not affected with cavitation effect produced by ultrasound of frequency of 500×500 kHz. The carbon loss was less. The rate of loss was only 0.6%. In conclusion, ultrasound was used as alternative method to regenerate activated carbon adsorbing with heavy metal ion.

Multi-Frequency Ultrasonic Extraction of Anthocyanins from Blueberry Pomace and Evaluation of Its Antioxidant Activity

2020 ◽  
Author(s):  
Ai-Jun Hu ◽  
Shu-Ting Hao ◽  
Jie Zheng ◽  
Lin Chen ◽  
Peng-Peng Sun
Keyword(s):  
Antioxidant Activity ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Extraction Yield ◽  
Single Frequency ◽  
Ultrasonic Power ◽  
Extraction Temperature ◽  
Dual Frequency ◽  
Esi Ms ◽  
Frequency Ultrasound

Abstract Background A large amount of blueberry pomace is discarded and wasted. Objective To make full use of blueberry pomace and extract anthocyanins. Method Multi-frequency ultrasound was used to extract anthocyanins from blueberry pomace. The effects of different extraction conditions on the anthocyanin yields were studied. The antioxidant activity of anthocyanins was evaluated, and the main anthocyanin components were identified by HPLC-electrospray ionization (ESI)-MS/MS. Results The optimal anthocyanin extraction conditions were as follows: dual-frequency ultrasound of 40 + 80 kHz, ultrasonic power of 350 W, extraction temperature of 50°C, and extraction time of 40 min. Compared with single frequency (25 kHz) and tri-frequency ultrasound (25 + 40 + 80 kHz), the anthocyanin yield with dual-frequency ultrasound increased by 15.26% and 5.45% respectively. Furthermore, the antioxidant activities (DPPH, hydroxyl radical scavenging ability, and reducing power) of anthocyanins extracted with dual-frequency ultrasound were all higher than those without ultrasound. Seven kinds of anthocyanins were identified by HPLC-ESI-MS/MS. Conclusions Dual-frequency ultrasound had a higher extraction yield than single frequency ultrasound, tri-frequency ultrasound, and no ultrasound. Highlights Dual-frequency ultrasonic technology provides an effective approach for improving the extraction yield of anthocyanins from blueberry pomace.

An Experimental Investigation on the Effects of Heat and Mass Flux on Vapor Bubble Growth Characteristics in a Microchannel

2009 ◽  
Author(s):  
Zachary Edel ◽  
Abhijit Mukherjee
Keyword(s):  
Flow Rate ◽  
Heat Exchangers ◽  
Bubble Growth ◽  
High Speed ◽  
Flow Boiling ◽  
Bubble Formation ◽  
Flow Characteristics ◽  
Vapor Bubbles ◽  
Constant Flow Rate ◽  
Temperature Liquid

Micro heat exchangers are emerging as one of the most effective cooling technologies for high power-density applications. The design of micro heat exchangers is complicated by the presence of alternating flow regimes, which give way to flow boiling instability. Bubble formation inside microchannels can be correlated directly to flow boiling instability and can regulate flow characteristics and wall heat transfer when the bubbles grow to reach the microchannel hydraulic diameter. In this study, the growth of vapor bubbles in a single microchannel was examined using an experimental setup capable of measuring coolant flow rate, inlet and outlet liquid temperatures, and channel wall surface temperature. Liquid flow rate and wall heat flux were systematically varied while a high-speed camera was used to capture images of vapor bubbles forming in the channel. These images were used to compare bubble growth rates for a constant flow rate. The results provide fundamental understanding of the bubble growth process.

scholarly journals Effects of Dual-Frequency Ultrasound-Assisted Thawing Technology on Thawing Rate, Quality Properties and Microstructure of Large Yellow Croaker (Pseudosciaena crocea)

Foods ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 226
Author(s):  
Hao Cheng ◽  
Chuhan Bian ◽  
Yuanming Chu ◽  
Jun Mei ◽  
Jing Xie
Keyword(s):  
Water Holding Capacity ◽  
Single Frequency ◽  
Large Yellow Croaker ◽  
Dual Frequency ◽  
K Value ◽  
Quality Properties ◽  
Ultrasound Assisted ◽  
Thawing Rate ◽  
Water Holding ◽  
Frequency Ultrasound

This research evaluated the effects of dual-frequency ultrasound-assisted thawing (UAT) on the thawing time, physicochemical quality, water-holding capacity (WHC), microstructure, and moisture migration and distribution of large yellow croaker. Water thawing (WT), refrigerated thawing (RT), and UAT (single-frequency: 28 kHz (SUAT-28), single-frequency: 40 kHz (SUAT-40), dual-frequency: 28 kHz and 40 kHz (DUAT-28/40)) were used in the current research. Among them, the DUAT-28/40 treatment had the shortest thawing time, and ultrasound significantly improved the thawing rate. It also retained a better performance from the samples, such as color, texture, water-holding capacity and water distribution, and inhibited disruption of the microstructure. In addition, a quality property analysis showed that the pH, total volatile basic nitrogen (TVB-N), and K value were the most desirable under the DUAT-28/40 treatment, as well as this being best for the flavor of the samples. Therefore, DUAT-28/40 treatment could be a possible thawing method because it improves the thawing rate and maintains the quality properties of large yellow croaker.

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