Search results

Novel aircraft propulsion configurations require a greater integration of the propulsive system with the airframe. As a consequence of the closer integration of the propulsive system, higher levels of flow distortion at the fan face are expected. This distortion will propagate through the fan and penalize the system performance. This will also modify the exhaust design requirements. This paper aims to propose a methodology for the aerodynamic optimization of the exhaust for novel embedded propulsive systems. To model the distortion transfer, a low order throughflow fan model is included.

As the case study a 2D axisymmetric aft-mounted annular boundary layer ingestion (BLI) propulsor is used. An automated computational fluid dynamics approach is applied with a parametric definition of the design space. A throughflow body force model for the fan is implemented and validated for 2D axisymmetric and 3D flows. A multi-objective optimization based on evolutionary algorithms is used for the exhaust design.

By the application of the optimization methodology, a maximum benefit of approximately 0.32% of the total aircraft required thrust was observed by the application of compact exhaust designs. Furthermore, for the embedded system, it is observed that the design of the compact exhaust and the nacelle afterbody have a considerable impact on the aerodynamic performance.

This paper presents a novel approach for the exhaust design of embedded propulsive systems in novel aircraft configurations. To the best of the authors’ knowledge, this is the first detailed optimization of the exhaust system on an annular aft-mounted BLI propulsor.

Improved value for money, plus a written guarantee against corrosion for two years or 24,000 miles is offered to motorists buying the Bainbridge Challenger aluminised steel replacement exhaust system. Announced recently by specialist exhaust system suppliers Richard Bainbridge & Son Ltd. of Bolton, Lancashire, a TI Silencer Group company, the aluminised steel exhaust system is immediately available for eleven popular saloon cars. They are: BLMC Mini MkI/MkII; 1100/1300 range; Marina 1·3/1·8 litre models; Morris Minor 1000; Rover 2000; Hillman Avenger; Ford Cortina MkII 1300/1600 models and the Vauxhall Viva HB. Systems for other models will become available during 1973. For ease of identification all the Bainbridge Challenger exhaust systems are painted a distinctive Maize Gold colour.

Development or upgradation of airplanes requires many different analyses, e.g. thermal, aerodynamic, structural and safety. Similar studies were performed during configuration change design of commuter category aircraft equipped with pusher turboprop engines. In this paper, thermo-fluid analyses of interactions of the new propulsion system in tractor configuration with selected elements of airplane skin are carried out. This study aims to check the airplane skin material, and its geometry, including the Plexiglas passenger window material degradation, due to hot exhaust gas plume impingement. The impact of change in exhaust stub angle and asymmetric inboard-outboard stubs on the jet thrust at various flight operating conditions like minimum off-route altitude and cruise performance is assessed.

Commercial software-based numerical models were developed. In the first stage, heat and fluid flow analysis was performed over a twin-engine airplane’s nacelle, wing and center fuselage with its powerplant mounted in the high wing configuration. Subsequently, numerical simulations of thermal interactions between the hot exhaust gases, which leave the exhaust system close to the nacelle, flaps and the center fuselage, were estimated for various combinations of exhaust stub angles with asymmetry between inboard-outboard stubs at different airplane configurations and operating conditions.

The results of the simulations are used to recommend modifications to the design of the considered airplane in terms of material selection and/or special coatings. The importance and impact of exhaust jet thrust on the overall aircraft performance are investigated.

The advanced numerical model for the exhaust jet-airplane skin thermal interaction was developed to estimate the temperature effects on the propeller blades and aircraft fuselage surfaces during different flight operating conditions with multiple combinations of stub orientations.

The purpose of this paper is to present the results of the preliminary design and optimization of the air-intake system and the engine nacelle. The work was conducted as part of an integration process of a turboprop engine in a small aircraft in a tractor configuration.

The preliminary design process was performed using a parametric, interactive design approach. The parametric model of the aircraft was developed using the PARADES™ in-house software. The model assumed a high level of freedom concerning shaping all the components of aircraft important from the point of view of the engine integration. Additionally, the software was used to control the fulfillment of design constraints and to analyze selected geometrical properties. Based on the developed parametric model, the preliminary design was conducted using the interactive design and optimization methodology. Several concepts of the engine integration were investigated in the process. All components of the aircraft propulsion system were designed simultaneously to ensure their compliance with each other.

The concepts of the engine integration were modified according to changes in the design and technological constraints in the preliminary design process. For the most promising configurations, computational fluid dynamics (CFD) computations were conducted using commercial Reynolds-averaged Navier–Stokes solver FLUENT™ (ANSYS). The simulations tested the flow around the nacelle and inside the air-delivery system which consists of the air-intake duct, the foreign-particles separator and the auxiliary ducts delivering air to the cooling and air-conditioning systems. The effect of the working propeller was modeled using the Virtual Blade Model implemented in the FLUENT code. The flow inside the air-intake system was analyzed from the point of view of minimization of pressure losses in the air-intake duct, the quality of air stream delivered to the engine compressor and the effectiveness of the foreign particles separator.

Based on results of the CFD analyses, the final concept of the turboprop engine integration has been chosen.

The presented results of preliminary design process are valuable to achieve the final goal in the ongoing project.

The purpose of this paper is to present the application of a procedure for the quality control of stainless steel tubes produced for automotive exhaust systems from a leading company in the steel sector, based on the Delphi method in accordance with the ISO/TS 16949:2009 and the ISO 9000:2008. Using Delphi methodology, it was possible to identify the main problems in the production lines object of the study, the main defects and their causes. Statistical methods were used to monitor process compliance and capacity. The panel of experts involved in Delphi method was able to identify causes of non‐compliance and suggest corrective actions.

The quality procedure implemented involves the application of the Delphi method and the ISO/TS 16949:2009 standard in conjunction with ISO 9000:2008 to the production line of welded tubes for exhaust systems. The statistical methods used to monitor the process were mainly control charts. Capability index, Cp and Cpk, were used to measure the process attitude to produce compliant outputs. Dimensional data were acquired by non‐destructive testing on diameters and X‐R charts were used to graphically represent the process state of control. Destructive tests were performed to monitor the welding quality and P‐chart were used to assess the proportion of nonconforming units.

In this work, a procedure was developed in order to characterize the production process of TXM tubes realized in the line 31 of the leader company plant. The use of Delphi methodology, in order to incorporate experts opinions in the quality control of stainless steel tubes, was one of the main points of this work. The panel of experts worked together to identify process issues, define their causes and propose corrective actions. The paper provides an overview about the quality approach of one of the world's largest companies in the production of steel and shows also how the statistical tools are used in order to manage process behavior.

The value of this paper is to illustrate an innovative approach to a real life quality problem; it demonstrates how the application of qualitative and quantitative quality instruments in accordance with technical specification can help in increasing and maintaining product compliance and in optimizing the management of resources.

The purpose of this paper is to present the challenges of turbine engine installation on small aircraft. The work was a part of the European Union project Efficient Systems and Propulsion for Small Aircraft, FP7 EU – Activity, 7.1.4. improving cost efficiency.

Few of the most interesting issues associated with replacing a piston engine with a turboprop engine were chosen: changes in engine bay cooling, air inlet, exhaust system, nacellès weight and parts reduction, flight tests and performance. The publication presents an approach to: design, assemble and test the small aircraft with a turboprop engine.

Replacement of piston engine by turbine was carried out. The full program of ground and flight test small aircraft has been successfully completed. Pros and cons of the new design are described in the paper.

Currently, aviation gasoline (AVGAS ) is increasingly being replaced by JET-A1 (kerosene-type fuels) or diesel fuel. The change concerns engine replacement and all the necessary additional components on the aircraft. This is consistent with the new directions of development of aviation: clean, green and eco design. Replacing the piston engine with a turbine allows improvement to performance and reduces operation cost.

The achieved results allow for identifying and highlighting new directions of aviation technology development. A significant added value is to draw attention to the necessity of preparing for future requirements and amendments in regulations for the new class of aircraft: general aviation SET(L) – single engine turboprop.

This paper aims to investigate the impact of heat recovery ventilators (HRVs) on the energy use and indoor radon in a one family detached house. Heat recovery ventilation systems, because of reducing ventilation loss through recovered exhaust air, can play a good role in the effectiveness of ventilation to reduce energy use. In addition HRVs can maintain pressure balance and outdoor ventilation rate at a required level to mitigate indoor radon level.

In this study, a multizone model of a detached house is developed in IDA Indoor Climate and Energy (IDA ICE 4.0). The model is validated using measurements regarding use of energy for heating, ventilation and whole energy use. The performance of the heat recovery ventilation system is examined with respect to radon mitigation and energy saving by measuring the radon concentration and analyzing the life cycle cost of a heat exchanger unit.

The results of the measurements and dynamic simulation showed that the heat recovery ventilation system could lead to 74 per cent energy savings of the ventilation loss, amounting to about 30 kWh m⁻² per year. Life cycle cost analysis used for assessing total costs and the result showed that using this system is quite cost‐effective and investment would payback during 12 years.

Limitations of this study generally refer to radon measurement and simulation because of radon complex behavior and its high fluctuations even during short periods of time.

Heat recovery ventilation systems with reducing radon concentration improve indoor air quality and decrease environmental problems with energy savings.

Using balanced heat recovery ventilation can have benefits from the viewpoint of environmental impacts and household economy.

Employment of a heat recovery unit to control indoor radon level is a new usage of this technology which along with energy savings can improve sustainable development.

THE first essential in the design of an efficient exhaust system is that the exhaust gases should be carried away from the engine and clear of the aircraft without undue increase in exhaust back pressure. A further consideration of equal importance is the elimination of noise.

The purpose of this paper is to investigate the effect of different guide fins structures (i.e. single-layer and double-layer guide fins) on the exhaust flow and thermal uniformity of the motorcycle exhaust thermoelectric generator.

One single-layer guide fins structure and three double-layer guide fins structures are numerically investigated in terms of exhaust flow uniformity with different exhaust properties. Then, the double-layer guide fins structure achieving the highest flow uniformity is fabricated and experimentally investigated on a motorcycle at different engine speeds together with the single-layer guide fins structure to evaluate the thermal uniformity.

The double-layer guide fins structure obtains a better flow uniformity and thermal uniformity compared to the single-layer structure. Among surveyed structures, the double-layer structure with three closed V-shape guide fins achieves the highest flow uniformity. This structure also improves the thermal uniformity from 3.0 to 90.1% in comparison with the single-layer structure in experiments.

In this paper, the double-layer guide fins structures are derived from the improvement of the single-layer guide fins structure. The fluid flow uniformity index is applied as a measure for assessing the exhaust flow uniformity. The enhancement of thermal uniformity of the double-layer guide fins structure is expected to increase the longevity and performance of the motorcycle exhaust thermoelectric generator.

The proposed use of unlatched, reverse swing flappy doors is becoming widespread in the design of residential common corridor smoke control systems. This article explores the conceptual arguments for and against the use of these systems.

This article relies on industry experience, with reference to relevant building design practices, standards and research literature, to categorise arguments. These are collated into four common areas of concern relating to compartmentation, reliability, depressurisation and modelling practices. A final comparison is made between different common corridor smoke control system types for these four areas.

The article highlights several concerns around the use of flappy door systems, including the enforced breaches in stair compartmentation, uncertainties around system reliability, the reliance on door closers as a single point of failure, the impact of day-to-day building use on the system performance and the false confidence that modelling assessments can provide in demonstrating adequacy. The article concludes in suggesting that alternative smoke control options be considered in place of flappy door systems.

Discussion on the use of flappy door smoke control systems has been ongoing within the fire engineering community for several years, but there is limited public literature available on the topic. By collating the common arguments relating to these systems into a single article, a better understanding of their benefits and pitfalls has been provided for consideration by building design and construction professionals.