Determination of the Effect of Walking on the Forced Convective Heat Transfer Coefficient Using an Articulated Mannikin
Abstract
This study addresses the effect of the walking motion on local convective heat transfer coefficient at various body sites, employing an articulated mannikin. The forced convective heat transfer coefficient (h sub c) is determined by the napthalene sublimation plate technique. Circular napthalene disks were affixed to various body segments of the articulated mannikin. The mannikin then simulated walking at four different gaits under constant temperature (30 deg C) and wind speed (0.4-0.7 m./sec depending on the body segment) in an environmental chamber. The amount of napthalene weight loss through sublimation was translated to h sub c using the Chilton-Colburn analogy between heat and mass transfer. The results showed that arm movement during walking, unexpectedly, diminished the effective local convective transfer coefficient. Increased gait actually resulted in a decrease in h sub c, as measured on the arms and legs. On the nonmoving body trunk, no significant difference in h sub c was observed with increased gait. When the mannikin was held stationary and the chamber wind speed increased, a corresponding increase in h sub c was observed. Thus during walking, motion of the swinging limbs, the pendulum or pumping effect, tends to decrease the forced convective heat transfer coefficient as observed locally on the limbs. For the walking gaits applied in this study, a 5-7% decrease in h sub c was observed.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1987
- Accession Number
- ADA186452
Entities
People
- E. Arens
- R. R. Gonzalez
- Shi Chang
Organizations
- United States Army Research Institute of Environmental Medicine