Nikhil Dev

An ISM approach for modelling the enablers in the implementation of Total Productive Maintenance (TPM)

Total Productive maintenance (TPM) is increasingly implemented by many organizations to improve their equipment efficiency and to obtain the competitive advantage in the global market in terms of cost and quality. But, implementation of TPM is not an easy task. There are certain enablers, which help in the implementation of TPM. The utmost need is to analyse the behaviour of these enablers for their effective utilization in the implementation of TPM. The main objective of this paper is to understand the mutual interaction of these enablers and identify the ‘driving enablers’ (i.e. which influence the other enablers) and the ‘dependent enablers’ (i.e. which are influenced by others). In the present work, these enablers have been identified through the literature, their ranking is done by a questionnaire-based survey and interpretive structural modelling (ISM) approach has been utilized in analysing their mutual interaction. An ISM model has been prepared to identify some key enablers and their managerial implications in the implementation of TPM.

Analysis of barriers of total productive maintenance (TPM)

In the highly competitive environment, to be successful and to achieve world-class-manufacturing, organizations must possess both efficient maintenance and effective manufacturing strategies. A strategic approach to improve the performance of maintenance activities is to effectively adapt and implement strategic TPM initiatives in the manufacturing organizations. Total productive maintenance (TPM) is not easy to adopt and implement, due to presence of many barriers. The purpose of this paper is to identify and analyse these barriers. A questionnaire based survey was conducted to rank these barriers. The results of this survey and interpretive structural modelling approach have been used to model and analyse key barriers and drive managerial insights.

A graph theoretic approach to evaluate the intensity of barriers in the implementation of total productive maintenance (TPM)

Total productive maintenance (TPM) is an innovative approach to maintenance which holds the potential for enhancing effectiveness of production facilities. But, implementation of TPM is not an easy task. Innumerable barriers are encountered in real-life cases during TPM implementation. It is very essential to evaluate the nature and impact of these barriers so that production and maintenance managers can cultivate some strategies to overcome these barriers. In the present exertion, a graph theoretic approach has been applied to find the intensity of these barriers through an index which is computed through a permanent function obtained from the digraph of TPM barriers.

System modeling and analysis of a combined cycle power plant

The performance of a combined cycle power plant (CCPP) and cost of electricity generation per unit is a function of its basic structure (i.e., layout and design), availability (maintenance aspects), efficiency (trained manpower and technically advanced equipments), cost of equipments and maintenance, pollutants emission and other regulatory aspects. Understanding of its structure will help in the improvement of performance, design, maintenance planning, and selection of new power generation systems. A mathematical model using the graph theory and matrix method is developed to evaluate the performance of a gas based CCPP. In the graph theoretic model, a directed graph or digraph is used to represent abstract information of the system using directed edges, which is useful for visual analysis. The matrix model developed from the digraph is useful for computer processing. Detailed methodology for developing a system structure graph, various system structure matrices, and their permanent functions are described for the combined cycle power plant. A top–down approach for complete analysis of CCPP is given.

Development of reliability index for cogeneration cycle power plant using graph theoretic approach

A logical approach based on graph theory and matrix method (GTMM) is developed for assessment of reliability index for a co-generation cycle power plant (CGCPP). For a humongous and multipart system such as CGCPP, reliability of its components or subsystems is closely intertwined and insuperable without taking the effect of others. For the ease of analysis CGCPP system is divided into four sub-systems. Reliability of CGCPP is modeled in terms of a reliability attributes digraph which is developed from system reliability digraph. Nodes in the digraph represent sub-system reliability and reliability of interrelations is represented by the directed edges. The digraph is represented by one-to-one matrix called as variable system reliability permanent matrix (VSRPM). A step by step procedure is developed for calculating variable permanent function for reliability (VPF-r) from VSRPM. A higher value of index implies that the plant is available with better reliability. The developed methodology is illustrated step-by-step with the help of an example.

Graph Theoretic Analysis of Advance Combined Cycle Power Plants Alternatives With Latest Gas Turbines

In the present work, graph theory and matrix method is used to analyze some of the heat recovery possibilities with the newly available gas turbine engines. The schemes range from dual pressure heat recovery steam generation systems, to triple pressure systems with reheat in supercritical steam conditions. From the developed methodology, result comes out in the form of a number called as index. A real life operating Combined Cycle Power Plant (CCPP) is a very large and complex system. Efficiency of its components and sub-systems are closely intertwined and insuperable without taking the effect of others. For the development of methodology, CCPP is divided into six sub-systems in such a way that no sub-system is independent. Digraph for the interdependencies of sub-system is organized and converted into matrix form for easy computer processing. The results obtained with present methodology are in line with the results available in literature. The methodology is developed with a view that power plant managers can take early decision for selection, improvements and comparison, amongst the various options available, without having in-depth knowledge of thermodynamics analysis.Copyright

Mathematical Modeling and Computer Simulation of a Combined Cycle Power Plant

This paper presents the simulation procedure developed to predict the performance of a combined cycle power plant from given performance characteristics of its main components. Effects of gas turbine and steam turbine cycle parameters on combined cycle power plant (CCPP) output in terms of efficiency, work output and power output, particularly analyzing the influence of ambient conditions on the plant performance. The results of the mathematical model, implemented in “Matlab” software, have been compared with the simulation results presented in literature. Result shows that as the compression ratio increase the increase in efficiency becomes less. Increase in work output is observed upto a pressure ratio of 18 after this it starts decreasing. Increase in TIT increases cycle work output and efficiency. Turbine outlet temperature decreases with increase in compression ratio. Combined cycle efficiency and output first increases with rise in drum pressure and then decreases. Increasing superheater temperature is found to increase the specific work output and efficiency of steam and combined cycle. Increasing superheater temperature is found to increase the specific work output and efficiency of steam and combined cycle. Lowering the pinch point and approach point also results in an improvement in the combined cycle performance, Specific heats are considered to be changing with temperature. The present work will make the base for exergy analysis of combined cycle for varying parameters.

Selection of cutting-fluids using a novel, decision-making method: preference selection index method

This paper presents a simple and systematic multi-criteria decision making methodology to select a cutting fluid for the given application using the preference selection index (PSI) method. In this methodology, cutting fluid is selected for a given machining application without considering relative importance between the selection attributes. Two real time examples are cited from the literature in order to demonstrate and validate the applicability and potentiality of PSI method in solving the cutting-fluid selection problem. It is observed that the relative rankings of the alternative cutting fluid as obtained using PSI method match quite well with those as derived by the past researchers.

Cutting-fluid selection using complex proportional assessment method

The selection of right cutting fluid in the industrial environment is an important and complex issue due to their negative effects on health, safety, and environment, legislation and public environmental concerns. Although a number of mathematical approaches are available in literature to evaluate, select and rank the cutting fluids for the given machining conditions, but there is still need for a simple and systematic methodology to guide the user in selection of right cutting fluid for the given machining application. This paper presents a logical methodology to select a right cutting fluid using a novel multiple attribute decision making (MADM) method, i.e., complex proportional assessment (COPRAS) method. Two illustrative examples are presented from the literature to illustrate the capability and potential of COPRAS method in selection of cutting fluid and the results obtained by the COPRAS method are compared with the results obtained by the past researchers.

Exergetic Analysis of Combined Cycle Power Plant With Single Steam Extraction

Combined Cycle Power Plant (CCPP) is one of the most efficient systems of energy conversion with different topping and bottoming cycles. One of the acceptable schemes, the combination of Brayton and Rankine Cycle, is analyzed for various design parameters. In the present analysis thermodynamic modelling of a CCPP with single steam extraction from bottoming Rankine Cycle is carried out to study the effect of Inlet Air Temperature (IAT), Cycle Ratio (CR), Turbine Inlet Temperature (TIT), air compressor and gas turbine efficiency on the first and second law efficiency. For parametric analysis computer programming tool Engineering Equation Solver (EES) is used and thermodynamic properties of many fluids and gases are inbuilt function of the software. From the results it is concluded that combustion chamber is the source of highest exergy destruction followed by heat recovery steam generator, gas turbine, air compressor and steam turbine. With increase in TIT, optimum CR is also found to be increased because both the gas turbine efficiency and the gas turbine exhaust temperature are increased for the optimum cycle ratio.Copyright