Influence of nozzle configuration on the flow field of multiple jets

Kannan, B. T.; Panchapakesan, N. R.

doi:10.1177/0954410017699008

Cited by 12 publications

(3 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The analysis shows that, when the distance between the discharge ports is larger, the interaction between sub-jets is smaller, but the mixing degree between the rear sub-jets and environmental water is greater in the flow direction of the environmental water. Kannan et al [20] calculated the thermal jet flow field from one discharge port to five discharge ports by using the open-source computing platform and compared it with relevant experimental data. The calculations show that the near field flow characteristics of porous jet are nonlinear.…”

Section: Introductionmentioning

confidence: 99%

The Influence of the Discharge Port Structure on the Infrared Characteristics of Underwater Vehicle Thermal Jets

Gao

2022

Applied Sciences

View full text Add to dashboard Cite

The circulating cooling water of underwater vehicle power systems is discharged through the discharge port and is mixed with the environmental water to form a thermal jet, which diffuses, floats up in the environmental water and displays infrared characteristics on the surface of the water body. In order to explore the influence of the discharge port structure on the infrared characteristics of underwater vehicle thermal jets, this paper adopts the methods of simulation analysis and experimental verification, and it establishes an underwater vehicle motion model based on the CFD computing software platform to design elliptic discharge port structures with different radius ratios and to compare their different thermal jet infrared characteristics. The influence of the oval discharge port radius ratio on the infrared characteristics of thermal jets is verified by the reduced-scale water tank experiment, and the authenticity of the simulation calculation method and design parameters is verified. On the basis of oval discharge ports, the number and distribution position of discharge ports are further designed to suppress the infrared characteristics of thermal jets and to improve the thermal stealth performance of underwater vehicles. According to the simulation calculation and experimental results, under the condition of the same discharge flow, as the radius ratio becomes smaller, the mixing heat transfer effect of the thermal jet becomes better, and the infrared characteristics become less obvious. Moreover, increasing the number of discharge ports and adopting the symmetrical arrangement of discharge ports can further strengthen the temperature attenuation of thermal jets and reduce the surface maximum temperature.

show abstract

Section: Introductionmentioning

confidence: 99%

The Influence of the Discharge Port Structure on the Infrared Characteristics of Underwater Vehicle Thermal Jets

Gao

2022

Applied Sciences

View full text Add to dashboard Cite

show abstract

“…Through the flow characteristics analysis, they demonstrated that the mixing between the swirling jets generated a temperature distribution along the centerline and near the blowing diffusers, while allowing the resulting jet to propagate. Kannan and Panchapakesan (2017) numerically studied multiple circular jets (from one to five) flowing into a calm air environment using Open FOAM computation code. They compared their findings to the available experimental data and found that it is the standard k-ε turbulence model that satisfactorily reproduces the non-linear decay of the mean axial velocity for the multiple jets case.…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Study of a Turbulent Multiple Jets Issued from Lobed Diffusers

Medaouar¹,

Loukarfi²,

Braikia³

et al. 2019

JAFM

View full text Add to dashboard Cite

A combined experimental and computational study of a turbulent multiple jet from lobed diffusers is performed. The main interest of these multiple lobed jets is to come up with the best configuration that improves the thermal and dynamic homogenization in air diffusion units that can be used for ventilation, heating and air conditioning of residential premises. Herein, the configuration of a central lobed jet surrounded by six equidistant peripheral lobed jets has been investigated. On the experimental level, flow velocities and temperatures were measured by a multifunctional thermo-anemometer. In terms of numerical simulation, the conservation equations of mass, momentum and energy are solved while involving four turbulence models, viz., the k-ϵ model, the k-ω, the shear stress transport (SST) k-ω model and the Reynolds Stress Model (RSM). The findings are compared with thermo-anemometer measurements. It turns out that the SST k-ω model is most appropriate for predicting the average flow characteristics.

show abstract

“…This non-linear behavior can be utilized in applications that need better mixing. It was also shown that usage of higher number of nozzles results in higher mixing (Kannan and Panchapakesan, 2017).…”

Section: Introductionmentioning

confidence: 99%

Effect of momentum flux distribution on multiple round jets

Kannan

Panchapakesan

2018

AEAT

View full text Add to dashboard Cite

Purpose This study aims to investigate the effects of nozzle momentum flux distribution on the flow field characteristics. Design/methodology/approach The nozzle configuration consists of a central nozzle surrounded by four nozzles. All nozzles have the same diameter and constant separation between nozzles. OpenFOAM® is used for simulating the jet flow. Reynolds-averaged Navier-Stokes (RANS) equations are solved iteratively with a first-order closure for turbulence. Pitot-static tube with differential pressure transducer is used for mean velocity measurements. The comparison of computed results with experimental data shows similar trend and acceptable validation. Findings According to the results, the momentum flux distribution significantly alters the near field of multiple turbulent round jets. Highly non-linear decay region in the near field is found for the cases having higher momentum in the outer jets. As a result of merging, increased positive pressure is found in the mixing region. Higher secondary flows and wider mixing region are reported as a result of momentum transfer from axial to lateral directions by Reynolds stresses. Research limitations/implications The present study is limited to isothermal flow of air jet in air medium. Social implications Optimum momentum flux distribution in multijet injector of a combustor can reap better mixing leading to better efficiency and lesser environmental pollution. Originality/value As summary, the contributions of this paper in the field of turbulent jets are following: simulations for various momentum distribution cases have been performed. In all the cases, the flow at the nozzle exit is subsonic along with constant velocity profile. To simulate proper flow field, a large cylinder-type domain with structured grid is used with refinements toward the nozzle exit and jet axis. The results show that the non-linearity increases with increase in momentum of outer jets. Longer merging zones are reported for cases with higher momentum in outer nozzles using area-averaged turbulent kinetic energy. Similarly, wider mixing regions are reported using secondary flow parameter and visualizations.

show abstract

Influence of nozzle configuration on the flow field of multiple jets

Cited by 12 publications

References 25 publications

The Influence of the Discharge Port Structure on the Infrared Characteristics of Underwater Vehicle Thermal Jets

The Influence of the Discharge Port Structure on the Infrared Characteristics of Underwater Vehicle Thermal Jets

Experimental and Numerical Study of a Turbulent Multiple Jets Issued from Lobed Diffusers

Effect of momentum flux distribution on multiple round jets

Contact Info

Product

Resources

About