Thermal-wet model of knitted double jersey based on backpropagation algorithm of neural network

Abstract

In this article, thermal resistance test and water vapor resistance test were experimented to obtain data of heat and humidity performance. Canonical correlation analysis was used on determining influence of basic fabric parameters on heat and humidity performance. Thermal resistance model and water vapor resistance model were established with a three-layered feedforward-type neural network. For the generalization of the network and the difficulty of determining the optimal network structure, trainbr was chosen as training algorithm to find the relationship between input factors and output data. After training and verification, the number of hidden layer neurons in the thermal resistance model was 12, and the error reached 10−3. In the water vapor resistance model, the number of hidden layer neurons was 10, and the error reached 10−3.

Simulation of coupled transient heat and water vapor transfer in porous fiber membrane with different fiber orientations and porosity

“…3 The transmission characteristics of water vapor adjust the transmission rate of sweat on the skin surface and improve the evaporation and heat dissipation of sweat. 4 The thermal comfort of the fabric is usually characterized by experimental tests of water vapor resistance ( R et ) and water vapor permeability ( W d ), 5,6 which reflects the heat convection and water vapor transmission. However, the R et and W d could not reveal the process of heat and water vapor transfer because the transfer of heat and water vapor is coupled and time-dependent.…”

“…7,8 Besides, polyurethane (PU) porous fiber membrane prepared by electrospinning is usually applied in thermally comfortable and breathable fabric due to the low R et and high water vapor transmission rate (WVT). 2,5 Nevertheless, porous fiber membrane possesses complex microstructures due to the discrepancy in fiber orientation and the porosity. 9 In general, the permeability ( κ ) of a porous medium is a geometric parameter of the porous structure, 10 which is resolved by the apparent velocity.…”