Study On Heat Transfer Mechanism Of Paper Honeycomb Filled With Recycled Foam

During transportation and storage,improper thermal insulation will lead to damage and failure of temperature sensitive products.It is very important to control the temperature sensitive products within an appropriate temperature range and pack the temperature sensitive products with thermal insulation.At present,polymer foamed plastics are usually used as thermal insulation materials,and the massive use of foamed plastics will cause serious environmental pollution.With excellent mechanical and thermal properties,paper honeycomb is expected to be a packaging material with both load bearing and thermal insulation functions.At the same time,foam plastic has excellent thermal insulation performance.If the waste foamed plastic can be used as the core filling material in the paper honeycomb,the effective thermal conductivity can be further reduced.Based on paper honeycomb and waste foam plastic,the preparation of new packaging box will have practical guiding significance for packaging design of temperature sensitive products.In order to evaluate the possibility of the application of new packaging box in thermal insulation packaging,the paper honeycomb and paper honeycomb filled with recycled foam were taken as the research objects,and the heat transfer performance was studied.The research contents mainly include:(1)According to the physical model of typical cell of paper honeycomb,the possible heat transfer modes and characteristics of paper honeycomb were analyzed,and the theoretical formulas of effective thermal conductivity of heat conduction,radiative heat transfer and convective heat transfer were provided.Furthermore,COMSOL Multiphysics was used to simulate and verify the air convection in paper honeycomb.Base on the measurement of the effective thermal conductivity of paper honeycomb under different conditions by steady-state heat transfer experiment,theoretical models for predicting the effective thermal conductivity of paper honeycomb were obtained by fitting experimental results.Then,the influence of air convection on the effective thermal conductivity of paper honeycomb was investigated.(2)The characteristics of heat transfer in granular packing structure were analyzed theoretically,and the theoretical models of effective thermal conductivity of different heat transfer paths in granular packing structure were given.EPS particles were selected as the filling material of paper honeycomb,and the paper honeycomb filled with recycled foam was prepared.The manufacturing process was given,and the structural characteristics of its typical units were described by porosity.The effective thermal conductivity of paper honeycomb filled with recycled foam was measured by steady-state heat transfer experiment,and the theoretical models for predicting the paper honeycomb filled with recycled foam composite structure were obtained by fitting the experimental results.The influence of natural convection on the effective thermal conductivity of paper honeycomb filled with recycled foam was further investigated.(3)Based on experimental and theoretical results,the influence mechanism of different factors on the heat performance of paper honeycomb were discussed,such as the heat transfer direction,the geometric parameters of paper honeycomb cell,particle size and particle thermal conductivity.The contributions of heat conduction,radiative heat transfer and convective heat transfer to the effective thermal conductivity of paper honeycomb and paper honeycomb filled with recycled foam were quantitatively investigated.(4)The new insulation packing box was designed and prepared by using paper honeycomb and EPS particles.The heat transfer process of the box was analyzed.The thermal insulation mechanism of the box was revealed.And the effects of box size and cold storage agent quality on the heat preservation time of new insulation packing box were studied.This paper expands the application field of paper honeycomb and recycled foam,enriches the packaging material system,and establishes the technological method and theory of preparing packaging materials with paper honeycomb and paper honeycomb filled with recycled foam as thermal insulation layer.Therefore,the research results have certain theoretical significance and engineering application value in thermal insulation packaging.