Heat Transfer Studies in Coiled Agitated Vessel with Varying Heat Input

Perarasu, V.T.; Arivazhagan, M.; Sivashanmugam, P.

doi:10.2202/1556-3758.2211

Cited by 21 publications

(13 citation statements)

References 10 publications

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“…Heat transfer in agitated vessels is carried through heat exchange surfaces, like jackets, helical coils, spiral coils, and vertical tubular baffles [5]. The surfaces of heat exchange are designed as a function of the area necessary to carry the heating or cooling, based on the overall heat transfer coefficient, which is a function of the dimensionless groups Reynolds, Prandtl, and Nusselt.…”

Section: Steady-state Operationmentioning

confidence: 99%

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Design of Heat Transfer Surfaces in Agitated Vessels

Rosa¹,

Júnior²

2017

Heat Exchangers - Design, Experiment and Simulation

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The project on heat transfer surfaces in agitated vessels is based on the determination of the heat exchange area, which is necessary to abide by the process conditions as mixing quality and efficiency of heat transfer. The heat transfer area is determined from the overall heat transfer coefficient (U). The coefficient (U) represents the operation quality in heat transfers being a function of conduction and convection mechanisms. The determination of U is held from the Nusselt's number, which is related to the dimensionless Reynolds and Prandtl's, and from the fluid's viscosity relation that is being agitated in the bulk temperature and the viscosity in the wall's temperature of heat exchange. The aim of this chapter is to present a summary for the literature concerning heat transfer in agitated vessels (equipped with jackets, helical coils, spiral coils, and vertical tube baffles) and also the many parameters of Nusselt's equation for these surfaces. It will present a numerical example for a project in an agitated vessel using vertical tube baffles and a 45°pitched blade turbine. Subsequently, the same procedure is held with a turbine radial impeller, in order to compare the heat transfer efficiencies.

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Section: Steady-state Operationmentioning

confidence: 99%

“…The expression to determine the h o can be obtained through the Buckingham's Pi theorem [5], similar to the determination of h i ; hence, Eq. (9) can be rewritten by modifying the Nusselt and Reynolds' numbers for agitation (Re a ), presented in Eq.…”

Section: Steady-state Operationmentioning

confidence: 99%

Design of Heat Transfer Surfaces in Agitated Vessels

Rosa¹,

Júnior²

2017

Heat Exchangers - Design, Experiment and Simulation

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“…Perarasu et al [6] measured and numerically modelled heat transfer in an agitated vessel with helical coil and propeller; however, they mainly focused on influence of nano-particles in the mixed liquid. The same authors [7] published other experimental results along with heat transfer correlations for a coiled agitated vessel with propeller and turbine impeller. The results were presented in the form of Nusselt number correlations depending on the impeller Reynolds number.…”

Section: Introductionmentioning

confidence: 97%

Analysis of heat transfer in a vessel with helical pipe coil and multistage impeller

et al. 2014

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Results of heat transfer coefficient measurements in an agitated vessel heated or cooled by the liquid media flowing in a helical pipe coil are presented in this paper. The multistage impeller made of two pitched six-blade impellers and adjustable clearance was used in a vessel with conical bottom. The transient method based on measuring the temperature dependency on time and solving the unsteady enthalpy balance was used to determine the heat transfer coefficients between the agitated liquid and the helical pipe coil. The results are summarized by the Nusselt number correlations, which describe the dependency on the impeller Reynolds number. The second part of this paper introduces a theoretical analysis of the flow in the liquid batch near the helical pipe coil. Based on the known pumping capacity of the multistage impeller, the characteristic velocity near the helical pipe coil can be evaluated. This characteristic velocity can be then used to determine the Nusselt number describing the heat transfer in a flow around a cylinder with the same cross-section profile as the helical pipe coil. A clear correlation between this Nusselt number and the integral Nusselt number is presented in this paper and introduces an alternative approach for prediction of heat transfer characteristics on the basis of hydrodynamic parameters describing an agitated system.

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“…Both, transient and steady‐state strategies are found in the literature when determining heat transfer coefficients. Some authors use both techniques, depending on scale .…”

Section: Introductionmentioning

confidence: 99%

Measurement of heat transfer coefficients in stirred single‐use bioreactors by the decay of hydrogen peroxide

Müller

Meusel

Husemann

et al. 2017

Engineering in Life Sciences

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Single‐use bioreactors are barely described by means of their heat transfer characteristics, although some of their properties might affect this process. Steady‐state methods that use external heat sources enable precise investigations. One option, commonly present in stirred, stainless steel tanks, is to use adjustable electrical heaters. An alternative are exothermic chemical reactions that offer a higher flexibility and scalability. Here, the catalytic decay of hydrogen peroxide was considered a possible reaction, because of the high reaction enthalpy of –98.2 kJ/mole and its uncritical reaction products. To establish the reaction, a proper catalyst needed to be determined upfront. Three candidates were screened: catalase, iron(III)‐nitrate and manganese(IV)‐oxide. Whilst catalase showed strong inactivation kinetic and general instability and iron(III)‐nitrate solution has a pH of 2, it was decided to use manganese(IV)‐oxide for the bioreactor studies. First, a comparison between electrical and chemical power input in a benchtop glass bioreactor of 3.5 L showed good agreement. Afterwards the method was transferred to a 50 L stirred single‐use bioreactor. The deviation in the final results was acceptable. The heat transfer coefficient for the electrical method was 242 W/m2/K, while the value achieved with the chemical differed by less than 5%. Finally, experiments were carried out in a 200 L single‐use bioreactor proving the applicability of the chemical power input at technical relevant scales.

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Heat Transfer Studies in Coiled Agitated Vessel with Varying Heat Input

Cited by 21 publications

References 10 publications

Design of Heat Transfer Surfaces in Agitated Vessels

Design of Heat Transfer Surfaces in Agitated Vessels

Analysis of heat transfer in a vessel with helical pipe coil and multistage impeller

Measurement of heat transfer coefficients in stirred single‐use bioreactors by the decay of hydrogen peroxide

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