TrabalhosGratuitos.com - Trabalhos, Monografias, Artigos, Exames, Resumos de livros, Dissertações
Pesquisar

Datos do laboratorio

Por:   •  2/5/2016  •  Projeto de pesquisa  •  5.776 Palavras (24 Páginas)  •  290 Visualizações

Página 1 de 24

Performance modelling of a microgasturbine at part-load operation

A. Lázaro-Alvarado a, M.A. González-Carmona b, J. C. C. Dutra b, A. Coronas a

a Universitat Rovira i Virgili, Tarragona, Spain,

andresfelipe.lazaro@urv.cat (CA), alberto.coronas@urv.cat

b Universidade Federal de Pernambuco Recife, PE, Brazil,

angelica.gonzalez@ufpe.br, charamba@gmail.com

Abstract:

The integration of absorption chillers in microtrigeneration systems based on microgasturbines is a viable option to increase efficiency. But, as a matter of fact, it is not  a simple procedure, because there many equipment to microtrigeneration system, that need to be characterized, and modelled, in order to develop computational tools, to help predictions, visibilities study, and optimizations.  This paper presents a study to analyse the accuracy of Malinowski’s analytical model to predict the behaviour a microturbine operating at part load at nominal conditions, or at non nominal conditions. It generate turbine and compressors pressure relations and performance equations, which are correlated with experimental data. It was developed a computational tool to simulate a microturbine in different conditions n of operation.  

It is composed to the analytical model and a thermodynamic model; simulate the turbine as a real cycle. It was used to compare numerical results with experimental data, obtained in CREVER Benchmark Test, at URV. The data obtained for many different tests were compared with the model results. At first, it was verified if this programs generate the same results of the above-mentioned author, not presented at this paper. Despite of have been developed based to different experimental data, the models agreed quite well with the experimental data from CREVER benchmark test. The model used in this paper, presented good results. So, it can be used to compose the microtrigeneration model under development.

Keywords:

Microgasturbine, Part-Load Operation, Performance Modelling, Semi-empirical Model.

  1. Introduction

The current energy demand in industrial buildings worldwide has increased exponentially, provided a similar increase in the future. Reference [1] offers an overview of current and future sustainable gas turbine technologies in an objective manner. In today's market, demand for energy is not solely electric; the supplying thermal energy to meet basic needs in this sector, such as air conditioning and/or cooling in general, are clear objectives of those working in this area. Microtrigeneration systems with gas turbines are considered thermally efficient, because its thermal inertia is low, which allows them to reach their full load in a short time, making them ideal for certain applications where load variations is required [2].

Microtrigeneration refers to the generation of electrical energy, heating and cooling, using different equipment of generation not exceeding in power either 100 kW (for Spain) or 150 kW (for Brazil). Microturbines are defined as machines that perform a thermal energy conversion using a single working fluid. Without the typical microturbine designed with one axis connecting the compressor, turbine and generator, the power range of microturbine in the market is 30 -250 kW. Many manufacturers retain the typical Brayton Microturbines regenerative cycle design, because of their smaller size, higher speed and range of the compression ratio being 3.5 to 4 [3].

In the competitive energy market, the profitability of the operation of microtrigeneration systems is based on the capacity and performance of the technology installed, although the prices of fuels and electricity (subject to greater variability and volatility) also have a great influence on economic profitability, it is necessary to take all of this information into account in order to predict the behaviour of the overall system, to calculate its properties more precisely, or to define the quantities demanded by energy services (with great seasonal variability and throughout the day), being not an easy task in today's market. The main goal of developing of a(semi-empirical) mathematical model of the gas microturbine is to determine the partial rated performance and charging system microtrigeneration formed by a microgasturbine that drives refrigeration by absorption, delivering electrical and thermal energy demand to a building. Nevertheless, meeting the demands of these buildings results in the microturbine working at part-load, deriving in the system loosing efficiency. This problem has been presented by modelling the typical Microturbines at part-load, in order to analyse and predict the behavior and performance of a given load Microturbines[4].

Several studies in the literature by various authors, thermodynamically and mathematical analysing the effects of the design parameters on the performance of an axis between the compressor, turbine and generator components using maps as  Okelah [5], have performed this study performance of a fixed geometry turbo shaft engine co-using component maps; Al Hamdan and Ebaid [6] have performed the modelling and simulation of a gas turbine engine ideal single axis. Aklilu et al [7] developed a mathematical model to simulate a part-load operation of a single shaft gas compressor turbine with variable geometry, while Zhang and Cai [8] have made the study of the performance of generalized components. For commercial reasons, the manufacturer of microturbine not yield maps published turbines and compressors in the open literature, hence the usefulness of universal formulas of performance.

With the availability of these formulas, the microgasturbine suitability for the intended use can be checked, to then predict their behaviour at different loads. The methodology used for the model is based on the laws of the thermodynamics cycles of heat engines, and relies on correlations developed by authors such as Malinowski and Lewandowska [3].

  1. Turbine Characteristic Curves – Analyti

  2. cal Model

This article uses an analytical model as proposed in Refs. [8, 9, 3], to calculate the performances of the main components of a microgasturbine [10]. It is an useful tool because the turbine manufactures didn’t provide an extensive data that permits to model and predict the turbine behavior at part-load and outside standard conditions. Its main equations, that calculate the pressure relations and efficiencies of the compressor and turbine, are dimensionless, parametrized to design parameters, and are functions of the relative turbine rotational speed, and the relative mass flow, as presented in the equations (1 - 3).

...

Baixar como (para membros premium)  txt (27.7 Kb)   pdf (445.9 Kb)   docx (87.1 Kb)  
Continuar por mais 23 páginas »
Disponível apenas no TrabalhosGratuitos.com