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The effects of air channel construction and design elements on heat transfer characteristics of bicycle helmets for commuters

Aljaste, Helena; Kuklane, Kalev LU and Heidmets, Sixten Sebastian (2015) 4th International Cycling Safety Conference In [Host publication title missing]
Abstract
The earlier studies in this measurement series defined the limits and aims for design process to create better ventilating helmets [1], and tested the insulation [2] and evaporative characteristics [3] of the designed mock-ups. In addition some of the tested mock-ups were modified to study more closely the factors that were expected to improve heat transfer from the bicycle helmets. The present paper covers making a new prototype that allowed modifications of the air channels and in- and outlet openings. In total 2 new helmet design concept mock-ups were created and tested with 13 modifications in comparison with 6 selected helmets from the previous studies including the modified versions. The mock-ups were tested at the Thermal... (More)
The earlier studies in this measurement series defined the limits and aims for design process to create better ventilating helmets [1], and tested the insulation [2] and evaporative characteristics [3] of the designed mock-ups. In addition some of the tested mock-ups were modified to study more closely the factors that were expected to improve heat transfer from the bicycle helmets. The present paper covers making a new prototype that allowed modifications of the air channels and in- and outlet openings. In total 2 new helmet design concept mock-ups were created and tested with 13 modifications in comparison with 6 selected helmets from the previous studies including the modified versions. The mock-ups were tested at the Thermal Environment Laboratory, Lund University for insulation and evaporative resistance. Dry tests for insulation were carried on at 20 °C temperature in a wind tunnel on a thermal head manikin at the chosen air velocities of 1.6 m/s on a bald head and 1.6 m/s and 6 m/s with the wig in order to simulate the effect of hair. Wet tests were carried out with textile skin on the head manikin, using the air velocity 1.6 m/s with and without the wig. As the main result it was concluded that a well ventilating helmet is characterized by less contact with the head, and proper air channels with strategically placed air inlets and outlets. Large openings worked much better than a several small ones, yet, the care has to be taken as too large openings reduce the helmet protective capabilities. The shape and other design related modifications of the air inlets and outlets had minimal effect on ventilation. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Chapter in Book/Report/Conference proceeding
publication status
published
subject
keywords
bicycle helmets insulation ventilation evaporative resistance design
in
[Host publication title missing]
editor
Otte, Dietmar
pages
8 pages
publisher
Medizinische Hochschule Hannover, Germany
conference name
4th International Cycling Safety Conference
language
English
LU publication?
yes
id
67c67fae-7173-43f6-99ba-bf8a2eccd684 (old id 7866943)
alternative location
http://www.icsc2015.eu/index.php?plugin=programproceedings_main
date added to LUP
2015-10-01 15:19:10
date last changed
2016-04-16 07:28:52
@inproceedings{67c67fae-7173-43f6-99ba-bf8a2eccd684,
  abstract     = {The earlier studies in this measurement series defined the limits and aims for design process to create better ventilating helmets [1], and tested the insulation [2] and evaporative characteristics [3] of the designed mock-ups. In addition some of the tested mock-ups were modified to study more closely the factors that were expected to improve heat transfer from the bicycle helmets. The present paper covers making a new prototype that allowed modifications of the air channels and in- and outlet openings. In total 2 new helmet design concept mock-ups were created and tested with 13 modifications in comparison with 6 selected helmets from the previous studies including the modified versions. The mock-ups were tested at the Thermal Environment Laboratory, Lund University for insulation and evaporative resistance. Dry tests for insulation were carried on at 20 °C temperature in a wind tunnel on a thermal head manikin at the chosen air velocities of 1.6 m/s on a bald head and 1.6 m/s and 6 m/s with the wig in order to simulate the effect of hair. Wet tests were carried out with textile skin on the head manikin, using the air velocity 1.6 m/s with and without the wig. As the main result it was concluded that a well ventilating helmet is characterized by less contact with the head, and proper air channels with strategically placed air inlets and outlets. Large openings worked much better than a several small ones, yet, the care has to be taken as too large openings reduce the helmet protective capabilities. The shape and other design related modifications of the air inlets and outlets had minimal effect on ventilation.},
  author       = {Aljaste, Helena and Kuklane, Kalev and Heidmets, Sixten Sebastian},
  booktitle    = {[Host publication title missing]},
  editor       = {Otte, Dietmar},
  keyword      = {bicycle helmets insulation ventilation evaporative resistance design},
  language     = {eng},
  pages        = {8},
  publisher    = {Medizinische Hochschule Hannover, Germany},
  title        = {The effects of air channel construction and design elements on heat transfer characteristics of bicycle helmets for commuters},
  year         = {2015},
}