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Market-based mechanisms such as the contract net protocol (CNP) are very popular for dynamic job allocation in distributed manufacturing control and scheduling. The CNP can be deployed with different configurations of the system elements. Every configuration corresponds to a basic or a hybrid topology. The subject of topology is generally discussed in the field of "distributed systems." Inspired from the notion of topology in the distributed systems, this paper proposes a ring-like model as a competitor for the web-like CNP-based job allocation within the concept of holonic manufacturing systems. Details of the algorithm for scheduling and assignment of jobs to resources in the ring structure is presented and its performance is compared with both CNP-based distributed model, and the centralized conventional scheduling of a real manufacturing case study involving a major turbine production plant. Comparison of performance indicators such as time and cost of operations shows that the distributed models clearly outperform the conventional practice with meaningful impact on the production economy. As a possible implementation strategy, a hybrid switching model, composed of both competing models, is proposed.

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Three-dimensional thermo-hydrodynamic analysis of gas turbine combustion chambers is of great importance in the power generation industry to achieve higher efficiency and reduced emissions. However, it is prohibitive to use a comprehensive full-detailed mechanism in their simulation algorithms because of the huge CPU time and memory space requirements. Many reduction approaches are available in the literature to remedy this problem. Here a new approach is presented to reduce large detailed or skeletal mechanisms of oxidation of hydrocarbon fuels to a low-cost skeletal mechanism. The method involves an integrated procedure including a Sensitivity Analysis (SA) and a procedure of Gradual Evaluation of Ignition Error (GEIE). The sensitivity analysis identifies reactions which have less effect on the flame temperature (T f) and also those with less effect on the NO concentration (X NO). Using the GEIE procedure also identifies reactions that have less effect on the ignition delay time (τign). In this process, three cutoff limits are selected for T f, X NO, and τign. The procedure is validated and examined for two different hydrocarbon fuels, i.e., methane and kerosene. The detailed mechanism of GRI-3.0 is used for methane, to produce a low-cost skeletal mechanism containing 118 reactions and 39 species. Similarly, a validated skeletal mechanism for kerosene including 382 reactions and 106 species is used to generate a low-cost skeletal mechanism including only 180 reactions and 79 species. The accuracy of the obtained skeletal mechanisms was investigated to predict the ignition delay and the flame temperature for ranges of inlet temperatures (T 0) of 1000–1800 K, combustion pressures (p c) of 1.0–30.0 atm, and equivalence ratios (ϕ) of 0.5–2.0 using a homogeneous IGNITION model. In addition, the applicability of the produced mechanisms to predict oxidation parameters such as flame temperature, velocity of burnt gas, concentration of the main fuel species, some minor radicals, and other selected species was investigated and validated for both skeletal mechanisms using homogeneous models PSR and PREMIXED over a range of different T 0 (300–1800 K), p c (1.0–30.0 atm), and ϕ values (0.5–2.0). Comparisons show that the two new skeletal mechanisms have a good agreement with similar known base mechanisms but offer a significant gain in terms of computational cost.

This paper attempts to model the formation of a manufacturing network based on the holonic manufacturing concept. An industrial case study involving a large network of Small and Medium-sized Enterprises (SMEs) has been carried out to investigate the processes underpinning the network formation and job allocation activities. An algorithm using agentbased (Contract Net Protocol) features has been developed to validate the holonic model with real-life industrial data. The simulation software was calibrated so that the model responds with a lead time value close to that obtained in the real life network by altering the network capacity. The results proved that the software and the model possess a good potential, as a benchmark, for the comparison of optimised and new experimental models of a manufacturing network based on holonic system.