Numerical modeling of heat transfer and fluid motion underneath infant bedding

Abstract

A three-dimensional (3D) numerical model of a virtual infant thermal manikin covered by a quilt with realistic dimensions was developed in this study to analyze the heat transfer and fluid motion characteristics in the quilt microclimate. The air permeation through the quilt was taken into account, and the quilt was modeled as a homogenous porous structure. Thirteen quilt configurations with varied air distributions, containing five levels of air volume underneath the quilt (AVU) and five levels of air volume inside the quilt (AVI), were constructed, and their impact on body heat loss was quantitively investigated. The simulation results showed that a decrease of 1 cm3 in AVU brought about a decrease of 2.5 W/m2 in overall heat flux for a 2 cm thick quilt. The body contact area with the mattress, the distance to the quilt opening, and the amount of surrounding air would alter the heat dissipation pathway and airflow pattern, producing a differential impact on the heat transfer at each body segment. Furthermore, an equation for predicting the comfortable ambient temperature of bedding systems was established. The quilt configurations mentioned in this work were able to maintain infants at a thermally neutral state at ambient temperatures between 10 °C and 24.5 °C, indicating the flexible adjustment of infant bedding in terms of sleep thermal comfort. The findings of the current study will contribute to the fundamentals of heat transfer of bedding and provide a feasible tool to assess the thermal performance of infant bedding.