Heat transfer and characteristic flow regions similarities between impinging jets and axial-flow impellers

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68407700%3A21220%2F16%3A00302991" target="_blank" >RIV/68407700:21220/16:00302991 - isvavai.cz</a>

Výsledek na webu

—

DOI - Digital Object Identifier

—

Jazyk výsledku

angličtina

Název v původním jazyce

Heat transfer and characteristic flow regions similarities between impinging jets and axial-flow impellers

Popis výsledku v původním jazyce

The impingement jet is well known to give a high heat transfer coefficient near the stagnation region where the jet impinges on the target plate, therefore it is widely used as an effective technology in many branches of industries. Impinging jet is provided high local heat and mass transfer coefficient also in mechanically agitated equipment.The ideal impinging jet is composed axial and tangential velocity components but the real impinging jet contain also radial velocity component. The objective of this work was put on finding of similarities in the flow and heat transfer characteristic between simulation results of a round impinging jet, results of experimental data obtained on an agitated vessel with an axial flow impeller and results of experimental data obtained on an agitated vessel with an axial flow impeller embedded in the draft tube with four baffles. In the case with an axial impeller in a draft tube was provided a clearly defined flow imitating a submerged confined jet impinging the vessel bottle. All experiments were performed in the single liquid phase on the bottom of a cylindrical agitated vessel with diameter 390 mm and without the baffles. In the case with a draft tube were used three axial six-blade impeller with pitched angle 30°, 45° and 60° and diameter 67 mm. The draft tube was situated in three different clearances above the vessel bottom. In the case without a draft tube was used only an impeller with pitched angle 45°. Heat transfer coefficient were determined using the electro-diffusion method based on the measurement of the limiting diffusion current on a working electrode for equimollar the ferri/ferro-cyanide system in alkaline solution. Small platinum electrodes of 0.5 mm diameter were positioned in the radial direction at the vessel bottom. Local heat transfer coefficients were calculated on the basis of the assumed analogy between mass and heat transfer process.

Název v anglickém jazyce

Heat transfer and characteristic flow regions similarities between impinging jets and axial-flow impellers

Popis výsledku anglicky

The impingement jet is well known to give a high heat transfer coefficient near the stagnation region where the jet impinges on the target plate, therefore it is widely used as an effective technology in many branches of industries. Impinging jet is provided high local heat and mass transfer coefficient also in mechanically agitated equipment.The ideal impinging jet is composed axial and tangential velocity components but the real impinging jet contain also radial velocity component. The objective of this work was put on finding of similarities in the flow and heat transfer characteristic between simulation results of a round impinging jet, results of experimental data obtained on an agitated vessel with an axial flow impeller and results of experimental data obtained on an agitated vessel with an axial flow impeller embedded in the draft tube with four baffles. In the case with an axial impeller in a draft tube was provided a clearly defined flow imitating a submerged confined jet impinging the vessel bottle. All experiments were performed in the single liquid phase on the bottom of a cylindrical agitated vessel with diameter 390 mm and without the baffles. In the case with a draft tube were used three axial six-blade impeller with pitched angle 30°, 45° and 60° and diameter 67 mm. The draft tube was situated in three different clearances above the vessel bottom. In the case without a draft tube was used only an impeller with pitched angle 45°. Heat transfer coefficient were determined using the electro-diffusion method based on the measurement of the limiting diffusion current on a working electrode for equimollar the ferri/ferro-cyanide system in alkaline solution. Small platinum electrodes of 0.5 mm diameter were positioned in the radial direction at the vessel bottom. Local heat transfer coefficients were calculated on the basis of the assumed analogy between mass and heat transfer process.

Druh

O - Ostatní výsledky

CEP obor

JP - Průmyslové procesy a zpracování

OECD FORD obor

—

Projekt

<a href="/cs/project/GA14-18955S" target="_blank" >GA14-18955S: Experimentální a teoretická studie konvektivního přenosu tepla v rotujícím turbulentním impaktním proudu.</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2016

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů