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Process Intensification and Parametric Optimization in Biodiesel Synthesis Using Hydrodynamic Cavitation Reactors
Published in Veera Gnaneswar Gude, Green chemistry for Sustainable Biofuel Production, 2018
Parag r. Gogate, ashish v. Mohod
actual power dissipation into the liquid is important. Maddikeri et al. [42] estimated the actual power dissipation for the supplied power of 1.5 to where p2 is the fully recovered downstream pressure, pv is the vapor pressure of the liquid, p is the liquid density and v is the velocity at the constriction which can be calculated by knowing the main line flow rate and diameter of the orifice. It is important to understand that significant effects of cavitation will be obtained for cavitation number less than 1 (more specifically over the range 0.1 to 0.5). In some cases where dissolved gases are likely to be present, cavitation might occur over cavitation number range of 1 to 2.5 as well but very high intensity is not observed.
Sonochemical Synthesis of Go- Zno Nanophotocatalyst for the Degradation of Malachite Green Using a Hybrid Advanced Oxidation Process
Published in Nandakumar Kalarikkal, Sabu Thomas, Obey Koshy, Nanomaterials, 2018
Bhaskar bethi, shirish h. Sonawane, Bharat a. Bhanvase, vikas mittal, Muthupandian ashokkumar
Hydrodynamic characteristics of the cavitation device (orifice) were studied by measuring the main line flow rate and by using a dimensionless parameter called as cavitation number (Cv). The cavitation number is a dimensionless number used to characterize the condition of cavitation in hydraulic devices.19 Cavitation number for orifice device was calculated by considering the main line flow rate and cross sectional area of the orifice device. The calculated Cv for an orifice at an inlet pressure of 2 kg/cm2 is 0.11 (Cv = 0.11). The cavitation number is defined as Cv=P1-PV12pv2 $$ Cv = \frac{{P_{{\text{1}}} {\text{ - }}P_{{\text{V}}} }}{{\frac{1}{2}pv^{2} }} $$
Mechanical Displacement Pumps
Published in Igor Bello, Vacuum and Ultravacuum, 2017
The cavitation effect and consequential pump damage can be prevented when the inlet pressure of liquid ring pumps is increased as indicated by the cavitation number. Therefore, liquid ring pumps are equipped with systems that return a portion of discharged gases via controlled valves into the pump inlets. Cavitation does not occur if the liquid ring pumps operate with noncondensable gases.
Efficient production of biodiesel from Cannabis sativa oil using intensified transesterification (hydrodynamic cavitation) method
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Iftikhar Ahmed Khan, Naresh Prasad, Amit Pal, Ashok Kumar Yadav
Figure 5 shows the effect of upstream pressure on the conversion of raw C. sativa oil into biodiesel under optimum reaction conditions. The experimental results illustrate that the rate of transesterification reaction increases with an increase in upstream operating pressure of the system. Inlet pressure generated in the system mainly depends on type of cavitating device used and the capacity of the pump used for recirculation of liquid mixture. With an increase in the inlet pressure, velocity at the throat of cavitating device also increases, which subsequently reduces the cavitation number. As the cavitation number decreases, more number of cavities are formed which can result into higher cavitational yield. The results obtained using the orifice plate with 7 holes as a cavitating device show that there is an increase in the rate of transesterification reaction when upstream pressure increased from 1 bar to 3 bar, but beyond that there is no significant increase in the rate of reaction. This may be because, there is an increase in cavitation effect when operating pressure increased from 1 bar to 3 bar and beyond that there is no significant improvement in cavitation effect with operating pressure or the state of chocked cavitation has occurred. The reported results are consistent with other studies related to hydrodynamic cavitation (Patil and Gogate 2012).
Bubble dynamics of a pressure-driven cavitating flow in a micro-scale channel using a high density pseudo-potential Lattice Boltzmann method
Published in Heat Transfer Engineering, 2020
The computational domain of 600 × 120 (l/h = 5) and 1,200 × 120 (l/h = 10) are chosen for the transport of a single bubble in a fully developed flow between two plates at saturated condition corresponding to. The center of the bubble of radius 15 lu is placed at a distance of 100 lu from the inlet of the channel. The lateral boundaries are periodic while the top and bottom boundaries are no-slip walls. The relevant non-dimensional numbers in the simulation are Reynolds number, Cavitation number and Weber number (). The cavitation number predicts the occurrence of cavitation due to pressure gradient, velocity. A lower value of CN indicates a higher possibility of cavitation. The Weber number ranges between 0.01 () and 10. Simulations were performed at different Reynolds numbers (Re) and are summarized below.
Oxidation of Congo red by Fenton coupled with micro and nanobubbles
Published in Environmental Technology, 2023
Ping Ma, Chao Han, Qiongqiong He, Zhenyong Miao, Mingqiang Gao, Keji Wan, Enle Xu
In this study, MNBs were generated by the hydraulic cavitation generator based on a venturi tube. Cavitation number is a dimensionless parameter to characterize the cavitational intensity inside the cavitating device. The expression is as follow [22,23]: where P∞, μ∞ are hydrostatic pressure and velocity on undisturbed reference section in flow field, respectively. ρ is the density of the cavitating liquid medium. Pv is the saturated vapor pressure of the liquid at corresponding temperature. The cavitational effects are higher when the cavitation numbers are lower ideally [19,24].