Power Theft Prevention and Power Quality Improvement using Fuzzy Logic

This paper deals with Fuzzy logic based power theft prevention and power quality improvement. It involves comparison between the total load supplied by the distribution transformer and the total load used by the consumer and the error signal is used to identify the power theft. Load (energy) and voltage are fed as input to the Fuzzy logic controller and the corresponding change in output voltage is provided by the controller to improve the power quality and to prevent the power theft. Simulations are done using MATLAB and the results of the simulations are provided. It helps us to analyze the efficiency of intelligent control in electrical systems

Wake flow characteristics over an articulated lorry model with/without AC-DBD plasma actuation

The wake flow characteristics of a 1:20 scale articulated lorry model with a linear Alternate Current Dielectric Barrier Discharge (AC-DBD) plasma actuation implemented was experimentally investigated. Time-averaged velocity, turbulence, and vorticity information along the centreline of the model were constructed using a two-component particle image velocimetry technique. In addition, force balance was used to measure the time-average drag force acting on the model with and without the use of AC-DBD plasma actuation. In general, the AC-DBD plasma actuation showed negligible effect in changing the drag coefficient of the test model. Moreover, implementing the AC-DBD plasma actuation around the rear end of the trailer model could neither alter the size nor the reverse flow velocity in the wake region. In contrast, the AC-DBD plasma actuation increased the levels of fluctuation in the flow turbulence kinetic energy and vorticity but showed no observable effect to alter the frequency response of the flow in the wake region. It is deduced that the use of AC-DBD plasma actuation indeed generated no flow control effect at the rear end of an articulated lorry trailer

Conceptual design analysis for a two-stage-to-orbit semi-reusable launch system for small satellites

This paper presents the conceptual design and performance analysis of a partially reusable space launch vehicle for small payloads. The system employs a multi-stage vehicle powered by rocket engines, with a reusable first stage capable of glided or powered flight, and expendable upper stage(s) to inject 500 kg of payload into low Earth orbits. The space access vehicle is designed to be air-launched from a modified aircraft carrier. The aim of the system design is to develop a commercially viable launch system for near-term operation, thus emphasis is placed on the efficient use of high TRL technologies and on the commercial potential of the technical design. The vehicle design is analysed using a multi-disciplinary design optimisation approach to evaluate the performance, operational capabilities and design trade-offs. Results from two trade-off studies are shown, evaluating the choice wing area and thus aerodynamic characteristics, and the choice of stage masses and engines selection on the mission performance

Vehicle and mission design of a future small payload launcher

This paper presents the conceptual design and performance analysis of a partially reusable space launch vehicle for small payloads. The system uses a multi-stage vehicle with rocket engines, with a reusable first stage capable of glided or powered flight, and expendable upper stage(s) to inject a 500 kg payload in different low Earth orbits. The space access vehicle is designed to be air-launched from a modified aircraft carrier. The aim of the system design is to develop a commercially viable launch system for near-term operation, thus emphasis is placed on the efficient use of high TRL technologies. The vehicle design are analysed using a multi-disciplinary design optimisation approach to evaluate the performance, operational capabilities and design trade-offs

Conceptual design analysis for a two-stage-to-orbit semi-reusable launch system for small satellites

This paper presents the conceptual design and performance analysis of a partially reusable space launch vehicle for small payloads. The system uses a multi-stage vehicle with rocket engines, with a reusable first stage capable of glided or powered flight, and expendable upper stage(s) to inject 500 kg payload in different low Earth orbits. The space access vehicle is designed to be air-launched from a modified aircraft carrier. The aim of the system design is to develop a commercially viable launch system for near-term operation, thus emphasis is placed on the efficient use of high TRL technologies. The vehicle design are analysed using a multi-disciplinary design optimisation approach to evaluate the performance, operational capabilities and design trade-offs. Results from two trade-offs studies are shown, evaluating the choice wing area and thus aerodynamic characteristics, and the choice of stage masses and engines selection on the mission performance

How to launch small payloads? Evaluation of current and future small payload launch systems

This paper describes a preferable vehicle classification alongside a brief description of key technologies available on the shelf or under development to address the demand of the small payload market. This is followed by a discussion on the investigation of the current market and the future forecast; regarding the delivery of small payloads into orbit

A commercially driven design approach to UK future small payload launch systems

Miniaturisation of satellite componentry, increasingly capable small sensors and substantial increases in processing capacity and transmission bandwidth are driving rapid growth in small payload development and consequential launch demand. The advent of horizontal take-off spaceports opens the door for a new generation of small payload launch systems that will fulfil this demand. However, the key to a launch system's success is its ability to provide a return on the substantial costs of development while delivering pricing levels commensurate with the needs of launch customers. Therefore, commercially led design approaches are needed to refine and optimise the design of the new small payload launch systems required. This approach was embodied in an ongoing UKSA funded NSTP2 project titled Future UK Small Payload Launcher (FSPLUK). The approach is first founded upon a bespoke and specific market assessment. This characterises, segments and quantifies the commercial opportunity and establishes principal desired system performance requirements. An assessment of available technologies at differing TRLs permits initial vehicle configuration options to be developed and technically assessed. Technically viable options are then assessed in terms of commercial viability with the best advanced into more detailed technical assessment and system optimisation. The resultant vehicles are again tested for commercial viability and, if successful, emerge as recommended development avenues. Using these methods, it has been possible to iterate design concepts from apparently simple yet economically sub-optimised stacked launcher systems through several design iterations to a resultant highly flexible and economically efficient conceptual design. The key finding relates to the inter-relationship between payload flexibility, in permitting maximised flight rates from a reasonably complex but highly reusable first stage design, and low disposable upper stage unit cost. This has driven the resultant system to feature an air launched integrated re-usable first stage vehicle, configured with a flexible internal payload bay from which one or more upper stages are deployed. This configuration maximises commercial utility and reusability. The resultant high flight rate allows development costs to be efficiently amortised with minimised direct launch costs. The configuration therefore meets low cost per kg price targets while delivering a positive return on development expenditure over life. It also provides a flight proven vehicle platform with available internal real-estate for application as a hypersonic air test platform for new propulsion systems, such as SABRE. The commercially led approach has created the foundation for viable and economically justifiable development

Image processing techniques for shock wave detection and Tracking in High Speed Schlieren and Shadowgraph Systems

Schlieren and shadowgraph photography has been widely used to offer insight into the flow field in aerospace engineering due to their ease of application. The high-speed schlieren and shadowgraph techniques are typically applied to investigation of unsteady shock wave structure including shock reflection patterns and shock wave/boundary layer interactions, etc. Generally, qualitative analysis is performed based on the schlieren and shadowgraph image sequences. To process and analyze the large data set of the high-speed schlieren and shadowgraph images quantitatively, especially for the shock wave detection and tracking, a software was developed based on MATLAB GUI and its image processing toolbox. In this study, the image processing techniques exploited in the software, such as background subtraction, filter, threshold, edge detection, and shock tracking are presented. A case study on the phenomena of shock wave reflection from a solid surface was conducted. The results show that the proper filter method and the background image subtraction can effectively eliminate the image noises in frequency domain, which makes it easier to analyze the flow structure. Moreover, the instantaneous locations of shock waves are detected accurately, and the shock wave propagation speed calculated using the developed software are consistent with those of previous studies

Surface roughness benefits in open cavity flows

In the current study, we report the effect of distributed roughness elements on the flow characteristics within a rectangular cavity using a series of high-fidelity eddy-resolving simulations. A cavity with a length to depth ratio (L/D) of 3 is considered. Simulations are carried out at a Mach number of 0.2 and Reynolds numbers of 7000 and 19300, based on the free-stream velocity and the depth of the cavity. The cavity flows generate undesirable low-frequency pressure fluctuations due to the vortex impingement over the trailing edge of the cavity. We explore the possibility of employing distributed hemispherical roughness elements as a passive flow control strategy towards suppressing these pressure fluctuations. The roughness elements, modeled using the immersed boundary method, are placed upstream of the cavity leading edge and distributed along the span. For a given roughness configuration, we studied the effect of varying Reynolds numbers on the flow features generated by the roughness elements and their interaction with the growth of the separated shear layer using instantaneous and time-averaged flow fields. The roughness elements are shown to effectively reduce the sound pressure level (SPL) up to 7dB for the test cases considered

Surface roughness effects on cavity flows

Effects of three-dimensional (3-D) distributed roughness elements on the flow characteristics within a cavity are investigated using a series of high-fidelity eddy-resolving simulations. The cavity flows generate undesirable low-frequency pressure fluctuations due to the vortex impingement over the trailing edge of the cavity. We explore the possibility of employing distributed hemispherical roughness elements as a passive flow control strategy towards suppressing these pressure fluctuations. A rectangular cavity with a length to depth ratio, L/D, of 3 is considered. Simulations are carried out at a Mach number of 0.2 and Reynolds numbers of 7000 and 19300, based on the free-stream velocity and the depth of the cavity. The effect of sparsely and densely packed roughness elements on the stability of shear layer separating from the cavity are brought out. Pre-transitional fluctuations generated by the roughness elements (a) resulted in transitional/turbulent flow at the cavity leading edge for low/high Reynolds numbers (b) promoted an earlier breakdown of the large-scale coherent structures in the shear layer (c) are beneficial in decreasing the ‘cavity tones’ and the associated sound pressure levels (SPL) by 5-13 dB. Reduction in SPL is observed to be prominent at higher Reynolds numbers and with dense spacing between the roughness elements. At low Reynolds numbers, the benefit obtained by suppressing the ‘cavity tones’ can be eclipsed with an increase in the broadband noise