BLEVE Energy and Aerosol Formation: An Exergy Analysis

2014 ◽  
Author(s):  
Juan C. Ramirez ◽  
Suzanne A. Smyth ◽  
Russell A. Ogle
Keyword(s):  
Exergy Analysis ◽  
Initial Conditions ◽  
Pure Component ◽  
Bulk Liquid ◽  
Initial Kinetic Energy ◽  
Aerosol Formation ◽  
State Variable ◽  
Dead State ◽  
Surface Work ◽  
Maximum Work

The hazards from a boiling liquid expanding vapor explosion (BLEVE) include the formation of a blast wave and the projection of missiles. To understand the maximum work that can be obtained from a BLEVE, the authors have investigated in previous publications certain aspects of BLEVE behavior using exergy analysis. One of the key limitations in relating exergy calculations to more realistic behavior is the lack of knowledge of how the exergy of the explosion is partitioned into various types of work that occur in the BLEVE process. Some of these work terms include the formation and propagation of a shock wave, the strain work of vessel deformation and rupture into missiles, the initial kinetic energy of the missiles, and the surface work of aerosol droplet formation. In this paper we explore one of these work terms, the surface work performed in transforming the bulk liquid into aerosol droplets. The advantage of using exergy analysis to evaluate the maximum work of an explosion is that exergy is a state variable: its value depends only on the initial conditions of the high pressure fluid and the specification of the dead state. The methodology is illustrated for several pure component fluids.

Maximum Missile Velocity From Boiling-Liquid Expanding-Vapor Explosions (BLEVE) Using Exergy Analysis

2012 ◽  
Author(s):  
Juan C. Ramirez ◽  
Suzanne A. Smyth ◽  
Russell A. Ogle
Keyword(s):  
High Pressure ◽  
Kinetic Energy ◽  
Exergy Analysis ◽  
Initial Conditions ◽  
Saturated Vapor ◽  
Pure Component ◽  
Estimation Methods ◽  
Buffer Zones ◽  
Boiling Liquid ◽  
Dead State

One of the hazards from a boiling liquid expanding vapor explosion (BLEVE) is the formation and projection of missiles. The design of safeguards for protection from missiles, such as barricades or buffer zones, requires an estimate of the maximum kinetic energy of the missiles. In this paper we demonstrate the use of exergy analysis to estimate the maximum available work of the explosion, and then use a modified Gurney method to estimate the partitioning of exergy into the kinetic energy of the saturated vapor, the saturated liquid, and the missiles. The advantage of using exergy analysis to evaluate the maximum work of an explosion is that exergy is a state variable: its value depends only on the initial conditions of the high pressure fluid and the specification of the dead state. The advantage of using the Gurney method for evaluating the kinetic energy of missiles is that it does not require the selection of an equation of state for the high pressure fluid. The methodology is illustrated for several pure component fluids, and is then compared with other estimation methods.

Difference Synchronization of Identical and Nonidentical Chaotic and Hyperchaotic Systems of Different Orders Using Active Backstepping Design

2018 ◽  
Vol 13 (5) ◽  
Author(s):  
Eric Donald Dongmo ◽  
Kayode Stephen Ojo ◽  
Paul Woafo ◽  
Abdulahi Ndzi Njah
Keyword(s):  
Chaotic System ◽  
Initial Conditions ◽  
Lyapunov Stability Theory ◽  
The State ◽  
State Variables ◽  
State Variable ◽  
New Type ◽  
The Difference ◽  
Synchronization Scheme ◽  
Hyperchaotic Systems

This paper introduces a new type of synchronization scheme, referred to as difference synchronization scheme, wherein the difference between the state variables of two master [slave] systems synchronizes with the state variable of a single slave [master] system. Using the Lyapunov stability theory and the active backstepping technique, controllers are derived to achieve the difference synchronization of three identical hyperchaotic Liu systems evolving from different initial conditions, as well as the difference synchronization of three nonidentical systems of different orders, comprising the 3D Lorenz chaotic system, 3D Chen chaotic system, and the 4D hyperchaotic Liu system. Numerical simulations are presented to demonstrate the validity and feasibility of the theoretical analysis. The development of difference synchronization scheme has increases the number of existing chaos synchronization scheme.

Exergy Analysis-Potential of Salinity Gradient Energy Source

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Arash Emdadi ◽  
Mansour Zenouzi ◽  
Amir Lak ◽  
Behzad Panahirad ◽  
Yunus Emami ◽  
...  
Keyword(s):  
Sodium Chloride ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Exergy Analysis ◽  
Salinity Gradient ◽  
Electrical Energy ◽  
Dead State ◽  
Gradient Energy ◽  
Reference Environment ◽  
Faster Development

Mixing of fresh (river) water and salty water (seawater or saline brine) in a controlled environment produces an electrical energy known as salinity gradient energy (SGE). Two main conversion technologies of SGE are membrane-based processes: pressure retarded osmosis (PRO) and reverse electrodialysis (RED). Exergy calculations for a representative river-lake system are investigated using available data in the literature between 2000 and 2008 as a case study. An exergy analysis of an SGE system of sea-river is applied to calculate the maximum potential power for electricity generation. Seawater is taken as reference environment (global dead state) for calculating the exergy of fresh water since the sea is the final reservoir. Aqueous sodium chloride solution model is used to calculate the thermodynamic properties of seawater. This model does not consider seawater as an ideal solution and provides accurate thermodynamics properties of sodium chloride solution. The chemical exergy analysis considers sodium chloride (NaCl) as main salt in the water of this highly saline Lake with concentration of more than 200 g/L. The potential power of this system is between 150 and 329 MW depending on discharge of river and salinity gradient between the Lake and the River based on the exergy results. This result indicates a high potential for constructing power plant for SGE conversion. Semipermeable membranes with lifetime greater than 10 years and power density higher than 5 W/m2 would lead to faster development of this conversion technology.

Determining the Potential of Salinity Gradient Energy Source Using an Exergy Analysis

2016 ◽  
Author(s):  
Arash Emdadi ◽  
Mansour Zenouzi ◽  
Gregory J. Kowalski
Keyword(s):  
Sodium Chloride ◽  
Power Density ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Exergy Analysis ◽  
Salinity Gradient ◽  
Chloride Concentration ◽  
Semipermeable Membranes ◽  
Dead State ◽  
Gradient Energy

Mixing of fresh (river) water and salty water (seawater or saline brine) in a control fashion would produces an electrical energy known as salinity gradient energy (SGE). Two main conversion technologies of SGE are membrane-based processes; pressure retarded osmosis (PRO) and reverse electrodialysis (RED). In PRO, semipermeable membranes placed between the two streams of solutions allow the transport of water from low-pressure diluted solution to high-pressure concentrated solution. RED requires two alternating semipermeable membranes that allow the diffusion of the ions but not the flow of H2O. Lifetime and power density of the semipermeable membrane are two main factors affecting on deployment of PRO and RED. Semipermeable membranes with lifetime greater than 10 years and power density higher than 5 W/m2 would lead to faster development of this conversion technology. An exergy analysis of an SGE system of sea-river can be applied to calculate the maximum potential power for electricity generation. Seawater is taken as reference environment (global dead state) for calculating the exergy of water since the seawater is the final reservoir. Once the fresh water is mixed with water of the sea or lake it becomes unuseful for human, agricultural or industrial uses loses all its exergy. Aqueous sodium chloride solution model is used in this study to calculate the thermodynamic properties of seawater. This model does not consider seawater as an ideal model and provides accurate thermodynamics properties of sodium chloride solution. As a case study, exergy calculation of Iran’s Urmia Lake-GadarChay River system. The chemical exergy analysis considers sodium chloride (NaCl) as main salt in the water of Lake Urmia. The sodium chloride concentration is more than 200 g/L in recent years. Based on the exergy results the potential power of this system is 329 MW. This results indicates a high potential for constructing power plant for salinity gradient energy conversion.

Initial Conditions and Initialization of Fractional Systems

2016 ◽  
Vol 11 (4) ◽  
Author(s):  
Massinissa Tari ◽  
Nezha Maamri ◽  
Jean-Claude Trigeassou
Keyword(s):  
Initial Conditions ◽  
Fractional Order Systems ◽  
Fractional Systems ◽  
Infinite Dimensional ◽  
State Variable ◽  
Future Behavior ◽  
Fractional Integrator ◽  
True State ◽  
Fractional System ◽  
Dimensional Variable

In this paper, the initialization of fractional order systems is analyzed. The objective is to prove that the usual pseudostate variable x(t) is unable to predict the future behavior of the system, whereas the infinite dimensional variable z(ω, t) fulfills the requirements of a true state variable. Two fractional systems, a fractional integrator and a one-derivative fractional system, are analyzed with the help of elementary tests and numerical simulations. It is proved that the dynamic behaviors of these two fractional systems differ completely from that of their integer order counterparts. More specifically, initialization of these systems requires knowledge of z(ω,t0) initial condition.

Exergetic Efficiencies and the Exergy Content of Terrestrial Solar Radiation

2004 ◽  
Vol 126 (1) ◽  
pp. 673-676 ◽  
Author(s):  
Sean E. Wright ◽  
Marc A. Rosen
Keyword(s):  
Solar Radiation ◽  
Exergy Analysis ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Radiative Fluxes ◽  
Solar Engineering ◽  
Practical Performance ◽  
Maximum Work ◽  
Energy Conversion Devices ◽  
Better Than

In the field of solar engineering the practical performance of solar energy conversion devices is generally evaluated strictly on an energy (first law) basis. However, the second law of thermodynamics determines the maximum work potential or exergy content of radiative fluxes independent of any conceptual device. The work in this paper quantifies the effect of directional and spectral distribution of terrestrial solar radiation (SR) on its exergy content. This is particularly important as the thermodynamic character of terrestrial SR is very different from that of blackbody radiation (BR). Exergetic (second law) efficiencies compare the work output of a device to the exergy content of the radiative source flux rather than its energy flux. As a result, exergetic efficiencies reveal that the performance of devices in practice is always better than what is indicated by the corresponding energy efficiency. The results presented in this paper introduce the benefits of using exergy analysis for solar cell design, performance evaluation and optimization.

scholarly journals Energy and exergy analysis of counter flow wet cooling towers

2008 ◽  
Vol 12 (2) ◽  
pp. 69-78 ◽  
Author(s):  
Mani Saravanan ◽  
Rajagopal Saravanan ◽  
Sankaranarayanan Renganarayanan
Keyword(s):  
Direct Contact ◽  
Exergy Analysis ◽  
Cooling Tower ◽  
Transfer Principle ◽  
Contact Heat ◽  
Counter Flow ◽  
Dead State ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Direct Contact Heat Exchanger

Cooling tower is an open system direct contact heat exchanger, where it cools water by both convection and evaporation. In this paper, a mathematical model based on heat and mass transfer principle is developed to find the outlet condition of water and air. The model is solved using iterative method. Energy and exergy analysis infers that inlet air wet bulb temperature is found to be the most important parameter than inlet water temperature and also variation in dead state properties does not affect the performance of wet cooling tower. .

scholarly journals Identification, Estimation, and Control for Linear Uncertain Systems Using Measurements of Higher-Order Derivatives

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Zilong Shao ◽  
Gang Zheng ◽  
Denis Efimov ◽  
Wilfrid Perruquetti
Keyword(s):  
Uncertain Systems ◽  
Initial Conditions ◽  
Higher Order ◽  
The State ◽  
Identification Algorithm ◽  
Unknown Parameters ◽  
State Variable ◽  
Higher Order Derivative ◽  
Estimation And Control ◽  
And Control

In this paper, the problem of output control for linear uncertain systems with external perturbations is studied. First, it is assumed that the output available for measurement is only the higher-order derivative of the state variable, instead of the state variable itself (for example, the acceleration for a second-order plant), and the measurement is also corrupted by noise. Then, via series of integration, an identification algorithm is proposed to identify all unknown parameters of the model and all unknown initial conditions of the state vector. Finally, two control algorithms are developed, adaptive and robust; both provide boundedness of trajectories of the system. The efficiency of the obtained solutions is demonstrated by numerical simulation.

Exergy Analysis of Modern Fossil-Fuel Power Plants

1999 ◽  
Vol 122 (1) ◽  
pp. 1-7 ◽  
Author(s):  
J. H. Horlock ◽  
J. B. Young ◽  
G. Manfrida
Keyword(s):  
Power Plants ◽  
Exergy Analysis ◽  
Reversible Process ◽  
Turbine Plant ◽  
Maximum Work ◽  
Gas Turbine Plant ◽  
Definition Of ◽  
Fossil Fuel Power Plants ◽  
Ideal Process ◽  
The Ideal

The definition of open cycle rational efficiency is unequivocally based on the ratio of the actual shaft work output from a power plant to the maximum work that could be obtained in a reversible process between prescribed inlet and outlet states. However, different constraints may be applied to such an ideal reversible process, and the maximum work obtainable will then vary, as will the value of the rational efficiency. Attention has been drawn to this issue before in the literature and it is discussed further here. In particular, the consequences of defining the outlet state for the ideal process are critical. A further complication occurs when water or steam is injected into a gas turbine plant. Three definitions of rational efficiency are discussed here and some illustrative calculations presented. There are small but significant differences between the values of the three derived efficiencies. [S0742-4795(00)00101-0]

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