Jean-Pierre Nadeau

DESCRIPTION AND ANALYSIS OF TIMBER DRYING KINETICS

ABSTRACT In this paper an experimental and semi-analytical technique is described that provides a method of estimating a macroscopic drying kinetics curve and internal moisture content profiles is described. Moisture gradients and the time evolution of these gradients are analysed as a function of the air drying parameters (dry-bulb, wet-bulb temperature and the velocity) and the product parameters (thickness and density). The material used as an illustration is a maritime-pine-wood.

Interactive Design: Then and Now

An obvious fact of the present industrial epoch is the advancement of computing techniques that has strongly contributed to the emergence of engineering processes becoming more and more efficient, rapid and high-powerful. Computing Science has allowed efficient virtual tools to emerge. Nevertheless, today all industrial experts share the idea that computational tools do not represent a sufficient solutions for leading to innovation. Some strong transfers between Industry and Research have been developped in order to make around the virtual tools new techniques that lead to whole and complete solutions really ensuring a support to decision making in product engineering.

Aided Decision-Making for an Embodiment Design Problem

In the early phases of a traditional design process, many decisions are made by designers. For that purpose, they take advantage of their experience and company knowledge. These decisions are necessary in a sequential design process but may hide many embodiment solutions. Moreover, designers often use a trial-and-error mode to find a working combination of standard elements. To overcome these difficulties, a decision support system based on constraint programming is proposed. The object of the design process set out in this paper is to facilitate the embodiment design phase by avoiding a-priori decision making and searching for feasible architectures in which all the points of view of the various participants in the project are taken into account. A preliminary search of structuring characteristics of the design problem is necessary and is detailed here. This methodology is applied to embodiment design of the automatic weight-winding system of a monumental clock. To determine the most interesting solutions , objectives and performance indicators are entered. Finally, the benefits of our approach are discussed.

Knowledge Base Formulation for Aided Design Tool

In this article, a design support tool is developed and applied to a wind turbine. An analysis and structuring methodology is similarly investigated and applied. This methodology identifies structuring characteristics and provides a parsimonious overview of the design problem. The model is a set of constraints. The present approach uses functional analysis tools to get solutions at a given system level. These tools are completed by two TRIZ evolution laws and by functional flow analysis. The present analysis contributes to setting up models linked to functions and action verbs. These models can be treated as constraint-satisfaction problems. The present knowledge base is organised in terms of system and qualification levels, which leads to the generation of potentially validated solutions to continue with a detailed design process.

Flash Evaporation: Modelling and Constraint Formulation

The flash evaporation process has received growing recent interest in the agro-industry, particularly for the post-harvest treatment of grapes. This paper is devoted to the design and the optimization of a two-stage flash evaporator. An embodiment design approach of this process based on constraint satisfaction problem-solving techniques is presented. The aim is to perform the identification and the constraint formulation of the process model, especially the coupling between the two-stage evaporation chamber and the high and low pressures condensers. As an application, the functioning of a flash evaporator is studied using flow rates and temperatures defined on real number intervals. The problem is treated by a CSP solver involving the global physical model of the two-stage flash evaporator and the functional requirements. The analysis has been validated by several experimentations performed on a flash evaporator for the treatment of vintage and leads to a decision support system.

Qualitative Constraints in Integrated Design

Designers use mechanical calculus and their technical knowledge to give, propose and validate technical choices. Product perception and design reasoning are modeled using graphs. The knowledge used is defined through fuzzy-logic rules, qualitative analysis, analytical forms and reasoning is represented as a system of constraints. We give an example which aims at defining the technological choices of a lattice work of beams.

Conception Inversée Intégrée : prédimensionnement de produits par satisfaction de contraintes

Mechanical design is based on aims of schedule of conditions. Design is an inverted integrated process: designers use aims to do design choices. This process, which requires a translation of all objectives, allows the synthesis of ideal dimensions (choices of materials, dimensions and shapes) from explicit and implicit rules. Rules translate all process laws and mechanical laws: mechanical calculus is integrated in design. Inverted Integrated Design (IID) process is modelized from a constraint based representation and a qualitative valuation. Constraints are analytical or are build from neural networks. Consistency techniques are used in CSPs to seek all consistent dimensions. We apply our work to the design of some pressure apparatus.

Simulation of the High Temperature Drying of a Pasty Product: On the Influence of the Local Air Flow and the Thermal Radiation

Abstract This article deals with modeling and simulation of the industrial drying and calcination of a previously centrifuged pasty product. An experimental approach of this product is first carried out in terms of both product solvent content and product temperature during drying; using a previously designed devoted drying pilot system. An empirical model describing the product drying kinetics as a function of the industrial relevant controlled parameters is then derived. This model is based on the distinction of the convective power and radiative power supplies influence on the isenthalpic drying mass flux value; for this reason, it is suitable to up-scale the experimental product drying behavior from the pilot geometry to the industrial drier-calcinator geometry. This up-scaling approach, when combined with a classic mass and energy drying model, leads to derive a predictive tool for the product evolution in this industrial system.

Turbine Blade Cooling System Optimization

Designing high performance cooling systems suitable for preserving the service lifetime of nozzle guide vanes of turboshaft engines leads to significant aerodynamic losses. These losses jeopardize the performance of the whole engine. In the same time, a low efficiency cooling system may affect the costs of maintenance repair and overhaul of the engine as component life decreases. Consequently, designing cooling systems of gas turbine vanes is related to a multiobjective design problem. In this paper, it is addressed by investigating the functioning of a blade and optimizing its design by means of an evolutionary algorithm. Systematic 3D CFD simulations are performed to solve the aero-thermal problem. Then, the initial multiobjective problem is solved by aggregating the multiple design objectives into one single relevant and balanced mono-objective function; two different types of mono-objective functions are proposed and compared. This paper also proposes to enhance available knowledge in the literature of cooling systems of gas turbine vanes by simulating the internal cooling system of the vane. From simulations thermal efficiency and aerodynamic losses are compared and their respective influences on the global performances of the whole engine are investigated. Finally, several optimal designs are proposed.

Designing Dryers Using Heat and Mass Exchange Networks: An Application to Conveyor Belt Dryers

Classical 1-D numerical simulations of dryers involve the solution of non linear differential relations which include balance equations and transfer functions; namely, the drying rate equation and the heat transfer equation. These relations are integrated by means of the network theory and a new approach—the Number of Transfer Units method. This process leads to a non-linear algebraic system used to develop computer simulation programs. In this paper, the applications are based on the study of multiple-conveyor dryers. This type of dryer is used for many chemical engineering industrial applications to dry coarse particles (i.e., over 5 to 10mm) or for food engineering. Numerical simulations are performed to analyse the drying efficiency of these conveyor dryers. Due to the heat and mass numbers of transfer units and to the network idea, the computer programs run faster than classical ones. This program is involved in the expertise and study of the effectiveness ofmultiple-conveyor dryers. Some rules of behaviour of conveyor dryers are discussed and may be used in order to improve their design.