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Triangular orifices are widely used in industrial and engineering applications, including fluid metering, flow control, and measurement. Predicting discharge through triangle orifices is critical for correct operation and design optimization in various industrial and engineering applications. Traditional approaches like empirical equations have accuracy and application restrictions, whereas computational fluid dynamics (CFD) simulations can be computationally costly. Alternatively, artificial neural networks (ANNs) have emerged as a successful solution for predicting discharge through orifices. They offer a dependable and efficient alternative to conventional techniques for estimating discharge coefficients, especially in intricate relationships between input parameters and discharge. In this study, ANN models were created to predict discharge through the triangle orifice and velocity at the downstream of the main channel, and their effectiveness was assessed by comparing the performance with the earlier models proposed by researchers. This paper also proposes a novel hybrid multi-objective optimization model (NSGA-II) that uses genetic algorithms to discover the best values for design parameters that maximize discharge and downstream velocity simultaneously.

Chemical fibers are typically spun with a spinneret, whose cross-sectional shape may be round, cross, trilobal, etc. On the contrary, cellulose diacetate (CDA) fibers used as cigarette tows are commonly spun with a regular triangular prism spinneret having a regular triangular cross-section because the cross-section of the spun cigarette tow is Y-shape owing to acetone solvent evaporation in the spinning column and the filter efficiency of the cigarette tow can reach the maximum value. However, previously CDA tows or fibers produced with such a regular triangular orifice were seldom reported. Many parameters influence the CDA tow spinning process with die swell being one of the most important factors. In this study, a model of a die swell was developed using rheological knowledge and second-type surface integrals. In order to confirm the validity of the model, the die swell of a CDA spinning dope at the exit of a regular triangular orifice was determined with a travelling microscope. Further, each parameter of die swell was studied. The apparent viscosity of the CDA spinning dopes was determined for different mass concentrations and temperatures with respect to shear rate and storage modulus and loss modulus with different mass concentrations and temperatures versus angular frequency were measured with a Physica MCR101 rheoviscometer. In addition, the flow rate was measured with a metering pump attached to the spinneret, and pressure drop was calculated from the above parameters. The results demonstrated that the die-swell ratio decreased when the dope temperatures were increased, but increasing trends were observed with dope concentrations and shearing rate. The experimental die-swell ratios were in good agreement with the calculated model results with less than ±6 % deviation. Therefore, this study can provide support for related CDA tows spinning studies.

The present paper attempts to reproduce the discharge coefficient (DC) of triangular side orifices by a new training approach entitled “Regularized Extreme Learning Machine (RELM).” To this end, all parameters influencing the DC of triangular side orifices are initially detected, and then six models are extended by them. For training the RELMs, about 70% of the laboratory measurements are implemented and the remaining (i.e., 30%) are utilized for testing them. In the next steps, the optimal hidden layer neurons number, the best activation function and the most accurate regularization parameter are chosen for the RELM model. As a result of a sensitivity analysis, we figure out that the most important RELM model simulates coefficient values with high exactness. The best RELM model estimates coefficients of discharge using all input factors. The efficiency of the best RELM model is compared with ELM, and it is demonstrated that the former has a lower error and better correlation with the experimental measurements. The error and uncertainty examinations are executed for the RELM and ELM models to indicate that RELM is noticeably stronger. At the final stage, an equation is proposed for computing this coefficient for triangular side orifices and a partial derivative sensitivity analysis is also carried out on it.

Hydraulic characteristics of orifice plates with multiple triangular holes in hydrodynamic cavitation reactor were experimentally investigated by use of three dimensional particle image velocimetry (PIV), high speed photography, electronic multi-pressure scanivalve and pressure data acquisition system, and numerically simulated by CFD software Flow 3D in this paper. Effects of number, arrangement and ratio of holes on hydraulic characteristics of the orifice plates were considered. Effects of arrangement and ratio of holes and flow velocity ahead of plate on cavitation number and velocity profile were compared. Distribution of turbulent kinetic energy and similarity of velocity profile were analyzed. And characteristics of cavitating flow downstream of the orifice plate were photographically observed by high speed camera. Also, a comparison with flow characteristics of orifice plate with hybrid holes (circle, square and triangle) was made.

One of the most inexhaustible forms of energy is the ocean wave. The conversion of this energy into a useful form of electrical energy is possible by a device of oscillating water column (OWC). This work aims to numerically analyse the effect of the triangular lip wall of the OWC wave energy converter on the hydrodynamic efficiency at different wave steepness conditions (Hi/λ), orifice ratios (ε), and relative openings (σ). This analysis uses commercial computational fluid dynamics (CFD) code ANSYS FLUENT software in a 3D numerical wave tank. The governing equations are discretized using FVM formulation, and the k-ε turbulence model is used. The inlet velocity method is used to generate the waves. The model was validated and verified with the experimental model published by Çelik and Altunkaynak (2019) and implemented for further improvement. The hydrodynamic efficiency (Eff) of the new model increases with relative openings increases and also increases with the decreases in wave steepness. This study shows an optimum efficiency of 76.30% at ε4 = 1.03%, σ =75%, and Hi/λ = 0.02. The information obtained from this numerical investigation of a new model is a highly relevant source, and it provides foresight in the design of the OWC wave energy converter.

The present study experimentally investigated the near-field flow mixing characteristics of two turbulent jets issuing from equilateral triangular and circular orifice plates into effectively unbounded surroundings,respectively.Planar particle image velocimetry（PIV） was applied to measure the velocity field at the same Reynolds number of Re=50,000,where Re = UeDe /with Ue being the exit bulk velocity and the kinematic viscosity of fluid,D e the equivalent diameters.The instantaneous velocity,mean velocity,Reynolds stresses were obtained.From the mean velocity field,the centreline velocity decay rate and half-velocity width were derived.Comparing the mixing characteristics of the two jets,it is found that the triangular jet has a faster mixing rate than the circular counterpart.The triangular jet entrainments with the ambient fluid at a higher rate in the near field.This is evidenced by a shorter unmixed core,faster Reynolds stress and centreline turbulence intensity growth.The primary coherent structures in the near field are found to break down more rapidly in the triangular jet as compared to the circular jet.Over the entire measurement region,the triangular jet maintained a higher rate of decay and spread.Moreover,all components of Reynolds stress of the triangular jet appear to reach their peaks earlier,and then decay more rapidly than those of the circular jet.In addition,the axis-switching phenomenon is observed in the triangular jet.

Cellulose diacetate (CDA) fiber used in cigarette tow is typically spun using a spinneret with triangular shaped cross section. The properties of the CDA fibers obtained by spinning are influenced by the interplay of various parameters, with the pressure drop being one of the most important parameters. In this paper, we have developed a pressure drop model based on the rheological information and second-type surface integrals. Meanwhile, we also experimentally determined the pressure drop of the CDA spinning dope derived from the wood pulp after pre-treatment, acetification and hydrolysis, on the basis of the differential pressure transducers mounted between the entry and exit of the spinneret with a triangular-shaped orifice. To compare the calculated and experimental results of the pressure drop, the apparent viscosity of the CDA spinning dopes with different mass concentrations was determined using a Physica MCR101 rheoviscometer. In addition, the flow rate of the spinning dopes through the orifices was determined to reveal the variations in pressure drop as a function of dope temperature, mass concentration and shearing rate. Results indicated a decrease in pressure drop with increase in dope temperature and shear rate. However, the pressure drop showed an incremental trend with flow rates or dope concentrations. The experimental data of pressure drop were in the good agreement with those calculated using the model, with deviations of less than ±8 %. The results obtained in this study can serve as a basis for understanding the various parameters controlling the spinning process.