Forced convection mass deposition and heat transfer onto a cylinder sheathed by protective garments

In chemical, biological, radiological, and nuclear protective clothing, a layer of activated carbon material in between two textile layers provides protection against hazardous gases. A cylinder in cross flow, sheathed by such material, is generally used to experimentally test the garment properties. This is, however, complicated and predictive...

Hybrid simulations of rarefied supersonic gas flows in micro-nozzles

We show that accurate predictions of gas flow and pressure in axisymmetric micro-thruster nozzles with throat diameters in the µm range, and thrusts in the µN range, cannot be performed using continuum based Computational Fluid Dynamics with slip flow boundary conditions, but can be performed by applying a static, one-way, state-based coupling...

Effects of wavy surface roughness on the performance of micronozzles

Recent trends in small-scale (~1 dm³) satellites motivate the further development of microscale propulsion subsystems. In the present paper, we focus on flow dynamics simulations of conical convergent-divergent micronozzles and on the increased importance of wall effects due to the decrease in the characteristic length of such small...

Evaluation of micronozzle performance through DSMC, navier-stokes and coupled dsmc/navier-stokes approaches

Both the particle based Direct Simulation Monte Carlo (DSMC) method and a compressible Navier-Stokes based continuum method are used to investigate the flow inside micronozzles and to predict the performance of such devices. For the Navier-Stokes approach, both slip and no-slip boundary conditions are applied. Moreover, the two methods have been...

Transient ALD simulations for a multi-wafer reactor with trenched wafers

For a large multi-wafer vertical batch ALD reactor, transient, 3-dimensional, multi-scale simulations have been performed for the TEMAH pulse step during a HfO2 ALD process. A bi-directional, multi-scale coupling has been established between continuum reactor scale simulations and molecular trench scale simulations. For describing the molecular...

Computational modelling of clothing performance

A multi-scale numerical study of the flow, feat, and mass transfer in protective clothing

A multi-scale study of the performance of protective clothing has been performed by coupling various types of numerical simulation of flow, heat and mass transfer. From meso-scale Direct Numerical Simulation, it was found that the flow underneath the clothing is laminar and periodic, with a magnitude much smaller than the free stream velocity....

Computational fluid dynamic modeling of fabric systems for intelligent garment design

Protective clothing provides laboratory and hazardous matenals workers, fire fighters, military persomel, and others with the means to control their exposure to chemicals, biologica1 materials, and heat souces. Depending on the specific application, the textile matenals used in protective clothing must provide high performance in a nnmber of...