Effect of torsion in a helical pipe flow

The development of a relatively simple mechanistic model for an industrial ethylene cracking furnace is described, including the estimation of selected model parameters to improve model predictions. Energy balance equations are developed to account for radiative, conductive, and convective heat transfer in the radiant section, and for convection and conduction in the ultra-selective heat exchanger (USX) and in the transfer line exchanger (TLE). Kinetic schemes by Ranjan et al. and Sundaram and Froment are used to model the cracking reactions. [1,2] The heat transfer model is combined with mass and momentum balances to model gas composition, pressure, and temperature changes as a function of position along the reactor tubes. Initial values and uncertainty ranges are assigned to 44 model parameters based on information in the literature and our industrial sponsor. A sensitivity-based technique and a mean-squared-error (MSE) criterion are used to select the appropriate subset of 22 parameters for tuning. Parameters are estimated and model predictions are validated using industrial data. Model predictions provide a good match to data that were not used for estimation.

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“…Cowperthwaite [13] 3.6.2 f hconv;g Vasudeviah and Patturaj, Nemeth and Bucsky [36,37] 3.6.3 [13] 3.6.4…”

Section: Transfer Line Exchanger (Tle)mentioning

confidence: 99%

“…Patturaj, Nemeth and Bucsky [36,37] 4.2.2 k w;U ¼ 1:58 Â 10 À12 T 3 to;U À 6:37 Â10 À9 T 2 to;U þ 2:10 Â10 À5 T to;U þ 9:14 Â 10 À3 Assael and Gialou [40] 4…”

Section: Vasudeviah Andmentioning

confidence: 99%

Modelling of heat transfer and pyrolysis reactions in an industrial ethylene cracking furnace

et al. 2017

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Section: Introductionmentioning

confidence: 99%

“…The effect of the curvature was a first-order one, whereas the effect of the torsion was a second-order one. Then, several researchers (Austin and Seader, 11 Kao, 12 Xie, 13 Chen and Jan, 14 Vasudevaiah and Patturaj, 15 and Zhang and Zhang 16 ) elucidated the higher-order effect of coil parameters by different methods. With the use of computational fluid dynamics (CFD), the flow characteristics of the helically coiled pipe have been presented in great detail for different coil parameters.…”

Section: Introductionmentioning

confidence: 99%

Secondary vortex-based analysis of flow characteristics and pressure drop in helically coiled pipe

Tang

Yuan

Malin

et al. 2017

Advances in Mechanical Engineering

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This article presents an investigation for the secondary flow characteristics and associated pressure loss in fluid flow through helically coiled pipe. Computational fluid dynamics is employed to analyze the pipe flow with various geometries, and the accuracy of the numerical methodology is validated by conducting corresponding experiments. The analysis performs a detailed parametric study involving the pressure loss, the secondary vortex motion, and the secondary vortex intensity for a range of coil diameters (D; ranging from 300 to 3000 mm) and pipe diameters (d; ranging from 50 to 90 mm). The pipe flow develops to a stable state with increase in coil diameter, while an increase in pipe diameter delays this development. Then, the secondary flow characteristics are analyzed to explore the pressure loss mechanism. The distorted streamline of secondary vortices and the enlarged deflection angle of secondary vortices are both factors contributing to the enhanced pressure loss. Furthermore, the effects of pipe flow development on the following flow characteristics such as the turbulence dissipation rate and the secondary vortex intensity are revealed. These characteristics all distribute regularly and reach lower values when pipe flow begins to a stable state.

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“…The flow in a helical pipe is affected by torsion as well and shows more complicated characteristics [1]. There have been many recent studies on the fully developed flow in a helical circular pipe under the influence of both curvature and torsion [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Investigation of helical flow by using tracer technique

Baytaş

Baydo

Karatepe

2013

EPJ Web of Conferences

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Abstract. The flow through coiled tubes is, in practice, important for pipe systems, heat exchangers, chemical reactors, mixers of different gas components, etc., and is physically interesting because of the peculiar characteristics caused by the centrifugal force. Therefore, it is not so easy to observe flow parameters in the helical pipe experimentally. Tracer techniques are being increasingly used to determine characteristics such as volume flow rate, residence time, dispersion and mixing process in industry. In this study, the flow in the helical pipe was obtained in the laboratory and investigated by using the tracer technique. The experimental system including the helical pipe was set up in the laboratory. In the experiments methylene-blue (C 16 H 17 N 3 S) has been used as the tracer. The experiments were successfully performed with different flow rates and their results were evaluated with the flow parameters.

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Effect of torsion in a helical pipe flow

Cited by 9 publications

References 4 publications

Modelling of heat transfer and pyrolysis reactions in an industrial ethylene cracking furnace

Modelling of heat transfer and pyrolysis reactions in an industrial ethylene cracking furnace

Secondary vortex-based analysis of flow characteristics and pressure drop in helically coiled pipe

Investigation of helical flow by using tracer technique

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