---
_id: '9175'
abstract:
- lang: eng
text: 'Multiple impinging jets are widely used for their enhanced heat and mass
transfer characteristics, especially for drying of material such as paper and
textiles. Efficient transport characteristics between a drying medium and the
material being dried as well as the jet impingement force acting on the force
sensitive products (i.e. paper, fabrics) or force sensitive surfaces (i.e. painted,
coated) are very critical in the industrial drying applications for the overall
performance of the operation. Many variables and influencing factors and parameters
need to be considered for the proper design of such multiple impinging jet systems.
At present, a complete understanding of the effect of all the design and operating
parameters is lacking. Designers should optimize the design parameters of industrial
drying equipment to achieve the minimum capital costs (size of the apparatus)
and running costs (energy consumption). In the framework of this thesis, the heat
and mass transfer rates and pressure force between the multiple impinging round
jets and moving surface are investigated numerically. Numerical simulations have
been conducted to characterize the impinging jet heat and mass transfer and pressure
force on a moving surface with an array of impinging round jets varying the following
parameters: jet Reynolds number, nozzle-to-surface distance, jet-to-jet spacing,
jet exit angle, relative surface curvature and relative surface velocity. Then,
the key controlling design variables such as the nozzle-to-surface distance and
the jet-to-jet spacing both normalized by the jet exit diameter (i.e., H/d and
S/d), the jet exit velocity, the surface velocity and the jet exit angle have
been considered for a design optimization. Correlations describing the average
Nusselt number and pressure force coefficient for single row jet configurations
impinging on the flat and curved surfaces have been developed. The present work
illustrates that it is possible to address the effects of the complex flow phenomena
as encountered in industrial drying process using generic CFD codes with good
results. Thus complex and extensive computations based on elaborate and time consuming
turbulence modelling (i.e. RSM or LES) may be avoided as well the expensive measurements
of jet arrays impinging on moving surfaces. Using the correlation equations derived
from the computations the dependencies for the main parameters over a wide range
may be easily be determined. The analysis of the flow fields showed many different
phenomena interacting, leading to different flow regimes. In order to assess these
phenomena further investigations, preferably based on LES and DNS modelling and
flow measurements are needed. Keywords: Multiple jets, Heat transfer, Pressure
force, Energy consumption, Surface motion, Surface curvature, Optimization'
author:
- first_name: Ali
full_name: Chitazan, Ali
last_name: Chitazan
citation:
ama: Chitazan A. Heat and Mass Transfer from Jet Impingement Flow for Drying
Machines. Gottfried Wilhelm Leibniz Universität; 2022. doi: https://doi.org/10.15488/11879
apa: Chitazan, A. (2022). Heat and mass transfer from jet impingement flow for
drying machines. Gottfried Wilhelm Leibniz Universität. https://doi.org/ https://doi.org/10.15488/11879
bjps: 'Chitazan A (2022) Heat and Mass Transfer from Jet Impingement Flow
for Drying Machines. Hannover: Gottfried Wilhelm Leibniz Universität.'
chicago: 'Chitazan, Ali. Heat and Mass Transfer from Jet Impingement Flow for
Drying Machines. Hannover: Gottfried Wilhelm Leibniz Universität, 2022. https://doi.org/ https://doi.org/10.15488/11879.'
chicago-de: 'Chitazan, Ali. 2022. Heat and mass transfer from jet impingement
flow for drying machines. Hannover: Gottfried Wilhelm Leibniz Universität.
doi: https://doi.org/10.15488/11879,
.'
din1505-2-1: 'Chitazan, Ali: Heat
and mass transfer from jet impingement flow for drying machines. Hannover :
Gottfried Wilhelm Leibniz Universität, 2022'
havard: A. Chitazan, Heat and mass transfer from jet impingement flow for drying
machines, Gottfried Wilhelm Leibniz Universität, Hannover, 2022.
ieee: 'A. Chitazan, Heat and mass transfer from jet impingement flow for drying
machines. Hannover: Gottfried Wilhelm Leibniz Universität, 2022. doi: https://doi.org/10.15488/11879.'
mla: Chitazan, Ali. Heat and Mass Transfer from Jet Impingement Flow for Drying
Machines. Gottfried Wilhelm Leibniz Universität, 2022, https://doi.org/ https://doi.org/10.15488/11879.
short: A. Chitazan, Heat and Mass Transfer from Jet Impingement Flow for Drying
Machines, Gottfried Wilhelm Leibniz Universität, Hannover, 2022.
ufg: 'Chitazan, Ali: Heat and mass transfer from jet impingement flow for
drying machines, Hannover 2022.'
van: 'Chitazan A. Heat and mass transfer from jet impingement flow for drying machines.
Hannover: Gottfried Wilhelm Leibniz Universität; 2022. 178 p.'
date_created: 2022-11-14T10:15:45Z
date_updated: 2024-08-05T06:54:23Z
department:
- _id: DEP6017
doi: ' https://doi.org/10.15488/11879'
keyword:
- Prallstrahlen
- Wärmeübertragung
- Druckkraft
- Energieverbrauch
- Oberflächenbewegung
- Oberflächenkrümmung
- Optimierung
language:
- iso: eng
page: '178'
place: Hannover
publication_status: published
publisher: Gottfried Wilhelm Leibniz Universität
status: public
supervisor:
- first_name: 'Birgit '
full_name: 'Glasmacher, Birgit '
last_name: Glasmacher
- first_name: Stephan
full_name: Kabelac, Stephan
last_name: Kabelac
- first_name: Georg Heinrich
full_name: Klepp, Georg Heinrich
id: '49011'
last_name: Klepp
title: Heat and mass transfer from jet impingement flow for drying machines
type: dissertation
user_id: '83781'
year: '2022'
...