Prime Mover System Research Articles

Selection of Propulsion System for Electric Amphibious Bus to Alleviate Traffic Congestion in the Jabodetabek Area

High vehicle growth in Jakarta is not balanced with traffic growth, the level of congestion in Jakarta continues to increase every year. To overcome this congestion, innovation is needed to utilize the river as a means of public transportation. The amphibious bus is an alternative public transportation option in the Jabodetabek area to break congestion. The amphibious bus design must be supported by a propulsion system that can operate on land and water. The amphibious bus propulsion system is a must, according to river conditions and operational requirements. The selection of the drive system is carried out by means of analysis The driving criteria factors needed according to the specifications of the amphibious bus are power, efficiency, size, cost, and maneuverability. These criteria become indicators in determining the type of mover. This study aims to select the prime mover system based on criteria and specification requirements. The selection uses the process hierarchy analysis (AHP) method by giving weight to the criteria for each driver, and type of mover in the water, namely waterjets, azimuth-podded, Paddle Wheels, Cycloidal Propellers and propulsion on land diesel engines, gasoline engines, and electric engines. The results showed that the order of the propulsion selection criteria was propulsion power being the top priority, followed by maneuverability, energy efficiency, cost, operational and investment, and propulsion size and weight. The results of the AHP show that the main options are propulsion systems in water, namely waterjets and diesel engine propulsion systems on land. System Water Jet has a propulsion power of 1000 kW, has high maneuverability, energy efficiency of 85%, and a maximum speed of 60 Km/hour so it can meet the specifications of an amphibious bus drive. For operations on land, the main choice of propulsion system for amphibious buses is a diesel engine with a power of 250 HP and 800 Nm of torque providing strong torque and a wide cruising range. This system has a range of up to 800 km, a maximum speed of 120 km/h, and exhaust emissions of Euro 5.

An Analysis of an Advanced Compressed Air Energy System (CAES) Using Turbomachinery for Energy Storage and Recovery and for Continuous On-Site Power Augmentation as an Air Brayton Cycle

Abstract A thermodynamic analysis of an advanced CAES for Distributed Power Generation (DPG) is presented that utilizes turbomachinery for energy recovery, but also gives continuous power generation to augment on-site power. The advanced CAES uses renewable energy such as wind power and solar PV in the power range of 1500 to 2500 kW plus recuperation of waste heat from the existing on-site prime mover to improve the utility of the energy storage system. The proposed system also utilizes battery storage to maintain high energy density storage, preferably without the need for costly electrical rectifying and inversion systems to improve the stabilization of power generation. This proposed system may be thought of as a “cross-over” system that combines CAES technology with electric battery storage technology, particularly if the stored electric power is used directly as D.C. power at an industrial facility. The direct use of stored energy from a battery as heat input to the proposed “cross-over” system also may be considered in some limited applications. The ideal application of the proposed system is for isolated DPG systems perhaps in remote sites utilizing “power islands” of renewable energy augmented with on-site fossil fuel prime mover, power generation systems. The proposed “cross-over” system enables higher reliability, faster response to transient power loads, and the efficient use of renewable energy, as well as heat recovery from conventional prime mover systems that are on site.

ACOUSTİC SİGNATURE OF TWO CUTTERS AND FOUR CUTTERS EV SWİRL STABİLİZED GASEOUS BURNERS

ABSTRACTToday’s gas turbine technology is established in a wide range of applications, including (i) the production of electrical power, (ii) thrust generation in turbojets and (iii) driving large size pumps and compressors. The greatest advantages of gas turbines against other prime mover systems e.g. steam turbine systems and piston engine systems, lie in its higher specific power, compact design and low initial costs based on power output.A major problem in gas turbine combustors is combustion instabilities which may cause many undesirable effects including; (a) increased noise levels, (b) oscillating thrust, (c) mechanical vibration that may lead to serious damage and even total loss of the system. These instabilities are characterized by large oscillations of the flow parameters, which in many circumstances may result in the inability of the combustion process to sustain these large oscillations; leading to partial or total flame blow-off. These combustion oscillations could, however be desirable as in pulsed combustors; as it enhance combustion intensity, increase thermal efficiency and reduce the emission of pollutants like NOx, CO and soot. In light of the above mentioned concepts, the present study is directed towards extending the previous studies on the recently introduced turbojet EV burner having two-circumferential swirling entry air passages by a four-circumferential swirling air entries configuration.This burner design concept appears to offer many advantages, including: The replacement of the traditional fixed vane swirler by circumferential swirling air passages; and hence not only minimizes blockage and allows prior premixing of fuel and air within the conically shaped entry section to the combustor but also eliminates possible risk in case of swirler blade damage.The study is an experimental investigations of the acoustic signature of a newly designed 4-slot EV burner. All the results are to be compared with those obtained by the previously developed 2-slot configuration. This allows the identification of the merits and/or drawbacks of both designs.

A Two-Level Forced Oscillations Source Location Method Based on Phasor and Energy Analysis

Forced oscillations (FOs), which are caused by sustained cyclic disturbances, threaten the safe and stable operation of power system. The most effective way to eliminate FOs is to locate the oscillation source and take corresponding measures. In this paper, a two-level method for forced oscillations source location is proposed. First, the energy structure of the generator is analyzed based on Hamiltonian function. The energy injected into generator is divided into two parts, i.e., energy injected by the prime mover system and excitation system. Then, as to the energy injected into power grid, the phasor relation between the variances of branch variables is analyzed to identify the energy flow direction. Based on the former analysis, the proposed method includes two levels. The bus level location of the oscillation source is realized according to the energy flow direction obtained with phasor analysis. Furthermore, the control device level location within the generator is realized according to the injected energy of the prime mover system and excitation system of generator. This method has good robustness for the measurement of data quality issue and is able to locate multimode oscillations with multiple disturbances. The simulation results in four-machine two-area system, East China power grid and the WECC 179-bus system as well as the comparison with classic energy-based method demonstrate the effectiveness and improvement of the proposed method.

Induction generator voltage improvement using a new control strategy for turbo-expander driving systems

Abstract Turbo-expanders are relatively new sources of dispersed generation which are used to drive the electrical generators. The conventional pressure regulating valves are replaced by these devices in the gas pressure reduction station. Connecting the dispersed generation to the distribution networks especially for squirrel cage induction generators, may result in some power quality problems. These problems can be obviated using special devices in electrical networks or modifying the control system of the prime mover system in mechanical parts. In this paper, it is focused on the Point of Common Coupling (PCC) voltage where a turbo-expander driven induction generator is connected. A new control strategy based on fuzzy controlled PID is considered for the mechanical part of the turbo-expander nozzle system. The results show a better control of turbo-expander output power in a linear form over the full range of operating points. The other purpose of the control system modification is to improve the power quality and stabilize the PCC voltage in different operating point conditions.

The Fast Estimation of the Electromechanical Oscillation Frequency

Analyzing stability of power system mainly relates to the model of machine, which can be simulated by two order and damping coefficient D (D represents mechanical damping and electrical damping), but there is no standard which can illustrate how much the damping coefficient D is. Usually power flow, excitation system, PSS and prime mover system affect the total damping largely, but have little impact on the electromechanical oscillation frequency. Firstly the paper theoretically proves the correctness of calculating electromechanical inherent frequency with system matrix. Secondly considering the damping ration characteristic of power system, the feasibility of estimating the electromechanical oscillation frequency with electromechanical inherent frequency is analyzed. With different models, the simulation results demonstrate that the electromechanical oscillation damping is affected very largely, but the frequency is affected little, which proves the effectiveness of the system matrix analysis method.

The Impact of Hydro-Turbine and its Governor System on Power System Low Frequency Oscillation

This paper studies the effect of the soft feedback in hydro-turbine and its governor system on power system transient stability. Low frequency oscillation phenomenon in which the hydraulic turbine sets participate occurred on power system many times this year, which with no mechanism discovered. In this paper, we first study the effect of mechanical load moment output of the prime mover system on the mechanism of low frequency oscillations, then by analysis of small-signal stability on hydro-turbine and its governor system and simulation experiments on an two-generator power system using PSASP, we come to the conclusion that: If the soft feedback output values of hydro-turbine governor systems are set small in the power system, it will come to the unstable oscillation condition.

Cool sound: the future of refrigeration? Thermodynamic and heat transfer issues in thermoacoustic refrigeration

During the past two decades the thermoacoustic refrigeration and prime mover cycles gained importance in a variety of refrigeration applications. Acoustic work, sound, can be used to generate temperature differences that allow the transport of heat from a low temperature reservoir to an ambient at higher temperature, thus forming a thermoacoustic refrigeration system. The thermoacoustic energy pumping cycle can also be reversed: temperature difference imposed along the stack plates can lead to sound generation. In this situation the thermoacoustic system operates as a prime mover. Sound generated by means of this thermoacoustic energy conversion process can be utilized to drive different types of refrigeration devices that require oscillatory flow for their operation, such as thermoacoustic refrigerators, pulse tubes and Stirling engines. In order for a thermoacoustic refrigeration or prime mover system as well as a thermoacoustic prime mover driving a non-thermoacoustic refrigeration system to be competitive on the current market, it has to be optimized in order to improve its overall performance. Optimization can involve improving the performance of the entire system as well as its components. The paper addresses some of the thermodynamic and heat transfer issues relevant in improving the performance of the thermoacoustic system, such as optimization for maximum COP, maximum cooling load and the role of the heat exchangers. Results obtained using the two optimization criteria are contrasted in the paper to illustrate the complexity of the optimization process.

Solving Polynomial Algebraic Equations of the Stand Alone Induction Generator

This paper describes the use of MathCAD's solving block which uses ‘Given’ and ‘Find’ built-in functions to solve nth order nonlinear algebraic equations. Introducing complex energy systems to electrical engineering students in their undergraduate studies is essential to complement many energy conversion courses. Various electric energy-capturing schemes use electric equivalent circuit models that incorporate nonlinear elements with complex mathematical formulas requiring numerical computation. Without incorporating programming tools, the taught material could be vague and a burden for both the student and the lecturer, hindering comprehension of the complexity of the system during the limited lecture hours. This paper introduces a ‘ready to use’ computational and mathematical tool that can be used to solve the non-linear equations quickly. The performance of an energy scheme with non-linear, interrelated variables such as the self-excited induction generator (SEIG) under variable excitation and loading conditions is used as an example. SEIG systems have been intensively proposed for energy capturing to supply power to remote areas from renewable energy resources such as wind and hydro prime mover systems.

熱駆動型発振器の基本特性に関する実験的研究

A thermoacoustic refrigerator and a thermoacoustic prime mover, because of its simple structure, would serve as very desirable systems, because thermoacoustic prime movers can be driven with waste heat, such as exhaust gas from engines, or with the heat from natures such as sunlight and geothermal heat. The combined thermoacoustic refrigerator and prime mover system would become a perfect cooling system without moving parts, CFCs, and HFCs. Thus this “Thermoacoustic-driven Thermoacoustic Refrigerator” will be a candidate for the next-generation refrigeration systems. In this paper, we set up our thermoacoustic prime mover to investigate the fundamental characteristics. On the prime mover tests, the fundamental characteristics of stack dimensions are mainly checked and the condition of the oscillation generation is observed with the instantaneous measurement of temperature and pressure oscillation. The way to improve the thermal efficiency of the prime mover is mentioned in terms of the operating condition.

Prime-mover response and system dynamic performance

Prime-mover response characteristics are influenced by the dynamics of turbines, boilers, and hydraulic systems, as well as by such control devices as speed governors and boiler-turbine controls. Some of the common types of prime-mover systems considered are the conventional single and double reheat systems, once-through units, and hydraulic turbine units. The pertinent phenomena are discussed, as are the implications of prime-mover response in the light of normal and emergency load-change duty.