An experimental study of temperature distribution in an autoclave

Abstract

In this work, the temperature distribution on an industrial mold tool is monitored during autoclave runs with three settings. In one of the settings, the temperature and pressure follow a scheme used in real moldings, while in the other two cases, the temperature is increased as fast as possible with and without an applied pressure. The temperature difference over the tool is relatively large and varies between 29 C and 76 C validating a detailed investigation of the temperature at different points. Two results of this are that positions on the up-stream side of the tool are heated faster than positions down-stream and the heating over the tool is symmetric while that within is asymmetric. Roughly estimated heat transfer coefficients reveal that the temperature ramping has no significant effect on the local heat transfer coefficients while the applied pressure more than doubled them. In addition flow field measurements with particle image velocimetry are performed, revealing a very slow flow near the roof of the autoclave and a velocity peak near the floor of it, indicating that the flow profile within the autoclave and variation in heat transfer coefficients should be considered in autoclave simulations.

Void‐Free Layered Polymeric Architectures via Capillary‐Action of Nanoporous Films

“…The conventional composite curing in this study was conducted with an autoclave, comprising a vacuum bag and applied pressure of 0.7 MPa, following the manufacturer's recommended cure cycle . A hot‐plate was utilized instead of a heating vessel (e.g., oven) for composite curing without an applied pressure (i.e., vacuum‐only curing), in order to avoid spatial gradients in cure due to uncertainty of convective‐to‐conductive interactions between the convective medium and cure materials . In the case of OoO curing, vacuum was applied via a vacuum bag without an applied pressure as the OoO curing is originally designed .…”

“…Additionally, even the use of OoA prepregs is not completely ideal from a manufacturing point of view. Heat transfer is still based on convection, which leads to inefficiencies and to spatial gradients in cure and stress due to convective‐to‐conductive interactions between the oven gas medium (usually air) and the cure materials . This method drives part‐to‐part variability, and the fabrication is still limited because of the fixed geometry of the heating vessel.…”

Design optimization of molds for autoclave process of composite manufacturing

“…At the higher temperatures (over 200 C) involved in thermoplastics processing, radiation is usually an important heat transfer mode in autoclave process. 20 However, as the temperatures typically used in the fabrication of thermoset composite materials is usually less than 200 C, forced convection is undoubtedly the major heat transfer process between parts and tooling and the surrounding gases inside an autoclave, 26 and the effect of radiation is considered unremarkable. [21][22][23][24][25] Therefore, the temperature distribution in an autoclave is mainly determined by the heat convection in fluid regions and heat conduction in solid regions.…”

“…From a thermal point of view, HTC between air and mold in different areas of the mold was determined by shift factors in Weber et al's 25 study. Moreover, an experimental study and numerical simulation were conducted by Kluge et al 19,26 to discuss the temperature distribution of a mold in the autoclave. Comparing with previous studies, the mold used in Kluge's research has a more complex shape, which contributed much to the turbulence of flow.…”

Research on Temperature Field Distribution in a Frame Mold during Autoclave Process

“…Chen et al [ 23 ] conducted a simulation of mold in the autoclave, which focused on the study of boundary layer grids to make the simulation results more accurate. Kluge et al [ 24 ] investigated the temperature distribution in the industrial mold in an autoclave. The results indicated that positions on the upstream side of the tool are heated faster than the downstream positions.…”