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

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Author

  • Helena Aljaste
  • Kalev Kuklane
  • Sixten Sebastian Heidmets

Editor

  • Dietmar Otte

Summary, in English

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.

Publishing year

2015

Language

English

Publication/Series

International Cycling Safety Conference 2015

Document type

Conference paper

Publisher

Medizinische Hochschule Hannover, Germany

Topic

  • Production Engineering, Human Work Science and Ergonomics
  • Design

Keywords

  • bicycle helmets insulation ventilation evaporative resistance design

Conference name

4th International Cycling Safety Conference

Conference date

2015-09-15 - 2015-09-16

Conference place

Medizinische Hochschule Hannover, Germany

Status

Published

Research group

  • Thermal Environment Laboratory