Flow characteristics of orifice spillway aerator: numerical model studies

Jothiprakash, V.; Bhosekar, V. V.; Deolalikar, P. B.

doi:10.1080/09715010.2015.1007093

Cited by 22 publications

(7 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The choice of the upstream area should follow the same principle as for the scale models. The sources of errors include the following issues [32][33][34][35][36]. The discussion here does not intend to be all-inclusive; it touches only on a few major aspects.…”

Section: Sources Of Errors In Cfdmentioning

confidence: 99%

The Past and Present of Discharge Capacity Modeling for Spillways—A Swedish Perspective

Yang

Andreasson

Teng

et al. 2019

Fluids

View full text Add to dashboard Cite

Most of the hydropower dams in Sweden were built before 1980. The present dam-safety guidelines have resulted in higher design floods than their spillway discharge capacity and the need for structural upgrades. This has led to renewed laboratory model tests. For some dams, even computational fluid dynamics (CFD) simulations are performed. This provides the possibility to compare the spillway discharge data between the model tests performed a few decades apart. The paper presents the hydropower development, the needs for the ongoing dam rehabilitations and the history of physical hydraulic modeling in Sweden. More than 20 spillways, both surface and bottom types, are analyzed to evaluate their discharge modeling accuracy. The past and present model tests are compared with each other and with the CFD results if available. Discrepancies do exist in the discharges between the model tests made a few decades apart. The differences fall within the range −8.3%-+11.2%. The reasons for the discrepancies are sought from several aspects. The primary source of the errors is seemingly the model construction quality and flow measurement method. The machine milling technique and 3D printing reduce the source of construction errors and improve the model quality. Results of the CFD simulations differ, at the maximum, by 3.8% from the physical tests. They are conducted without knowledge of the physical model results in advance. Following the best practice guidelines, CFD should generate results of decent accuracy for discharge prediction.

show abstract

Section: Sources Of Errors In Cfdmentioning

confidence: 99%

The Past and Present of Discharge Capacity Modeling for Spillways—A Swedish Perspective

Yang

Andreasson

Teng

et al. 2019

Fluids

View full text Add to dashboard Cite

show abstract

“…Numerical simulations were carried out at the physical model dimensions by Fluent software version 6.3 using the Finite Volume Method (FVM). To specify the boundary conditions and producing the flow grids, the gambit pre-processor [19] version 2.3.16 was chosen. For the computational cells, the optimal dimensions are determined (within the 0.005-0.025 m range).…”

Section: Numerical Modelmentioning

confidence: 99%

“…In smooth spillways with aerator, Yang et al [1] and Yang et al [18] used RNG k−ε turbulence for simulating two-phase air-water flow. Realisable k−ε turbulence model for this purpose has been used by Jothiprakash et al [19] and Teng and Yang [4]. Standard k−ε model has also been used for validation of the numerical model with aerator by Ozturk and Aydin [20].…”

Section: Introductionmentioning

confidence: 99%

A Comparative Assessment of Various Turbulence Models Applied for Simulation of Air-Water Flow Over Chute Spillway

Shayanseresht

Manafpour

2021

Period. Polytech. Civil Eng.

View full text Add to dashboard Cite

Chute aerators have been largely used to reduce cavitation hazard in high head spillways. There is no definite turbulence model for simulating these devices in smooth spillways in spite of its importance in critical conditions. A simulation in two-phase air-water chute flow and its aerator with five different turbulence models (RNG, Standard and Realizable k–ε Models, SST and Standards k–ω Models) has been numerically investigated by Fluent software. Finite Volume and VOF methods were used for discretization of flow equations and free surface modeling. Flow depth, velocity and bottom pressure comparison were made along with the air cavity length determination by numerical, experimental and reference equations. The best model with the minimum value of error percentage for flow depth and velocity was RNG k–ε turbulence model. The realizable and RNG k–ε turbulence models showed better results for the pressure head at the bottom of the chute. The RNG k–ε model results for the jet length have a very slight difference with the experimental results. The length of the cavity is closely associated with the flow emergence angle θ’ over aerators. The bottom air concentration of spillway chute simulated by all the turbulence models, except for the RNG k–ε model, can be overestimated and therefore may affect the designing of aerator geometry.

show abstract

“…The still growing interest strongly depends on their great practical significance in many industrial branches like food, biotechnology, bioprocess, environmental, chemistry and petrol engineering. That is because the TPFs are an important and ubiquitous component of numerous industrial processes like the aeration processes [144,68], chemical reactors [72], processes of flotation [147]. Some examples of TFP applications are summarized in Table 1.…”

Section: Introductionmentioning

confidence: 99%

Computer methods for non-invasive measurement and control of two-phase flows: a review study

Wajman

2019

ITC

View full text Add to dashboard Cite

Nowadays, the application of advanced technologies in modern production systems is the main trend of development and technological progress in many industrial sectors. It is due to the still growing trends of energy-saving and production quality enhancement. Wherever in the production process the phase mixture is transported and it is not optimal or not economic, there is a need to develop a system which would be able to prevent any construction disaster, unexpected production line stopping or situation where for reasons of bad flow parameters, the final product is defective. This paper studies various sensors, measurement techniques and computer methods for signal processing and analysis to diagnose and control two-phase flows. Due to the possibility that the invasive measurement disturbs the process and changes it parameters and behavior especially in the location just after the measurement point and simultaneously does not provide any information about these changes it is unreliable for the diagnosis or control. Therefore, the non-invasive techniques commonly used for measurement of flows parameters are described. Depending on the industrial demands many of applications examples for non-invasive two-phase flows measurement and monitoring are given. This description for identifying the flow parameters is divided into features categories of this phenomena as void fraction distribution, velocity profile and flow regime. However, from these methods the high accuracy and short processing time is expected. The continued observation and monitoring of the process abnormalities can provide valuable information about its dynamic state and allow for real-time and automatic monitoring and control. Therefore, the development of advanced process control is one of the most important challenges to keep the flow regime on the given level and for instant and long-term energy saving, quality improvement.

show abstract

Flow characteristics of orifice spillway aerator: numerical model studies

Cited by 22 publications

References 11 publications

The Past and Present of Discharge Capacity Modeling for Spillways—A Swedish Perspective

The Past and Present of Discharge Capacity Modeling for Spillways—A Swedish Perspective

A Comparative Assessment of Various Turbulence Models Applied for Simulation of Air-Water Flow Over Chute Spillway

Computer methods for non-invasive measurement and control of two-phase flows: a review study

Contact Info

Product

Resources

About