Numerical investigation of mutual interaction between a pusher propeller and a fuselage

Author(s):  
Marcin Figat ◽  
Paulina Piątkowska

This article presents the numerical analysis of the aerodynamic impact of the fuselage on propeller performance in the pusher configuration and the propeller impact on the flow around the fuselage. The main aim of the presented investigation was to find the magnitude of the interaction between the propeller and the fuselage. This effect was evaluated based on the analysis of the change of the fuselage drag and the propeller thrust according to the change of the propeller's geometry. All obtained results allowed to prepare the methodology for choosing the best propeller geometry for the aircraft in the pusher configuration. During the investigation, the impact of the propeller geometry on the results was analysed. First of all, the change of the blade pitch ratio and the propeller radius was tested. Computation was made for numerous flight conditions and propeller rotation rate. As a main result, the relation between the propeller performance and the fuselage in the pusher configuration was found. Especially, the significant influence on the propeller thrust caused by the fuselage and the influence on the fuselage drag caused by the propeller were observed. Finally, all the obtained outcomes were used to create a knowledge base, which was next used to select the best propeller geometry to satisfy the required power condition for a level flight for the newly designed aircraft PW-Chimera.

2013 ◽  
Vol 470 ◽  
pp. 284-288
Author(s):  
Qing Meng Meng ◽  
Xue Song Mao ◽  
Yu Shuo Fan ◽  
Si De Ling ◽  
Xuan Xiao

The change of moisture-heat is the key factor that influences the seasonal freezing subgrade stability. In order to analyze the impact of the moisture on temperature field in the seasonal frozen subgrade, this paper established seasonal freezing subgrade model, calculated and analyzed the effects of subgrade temperature field in the middle of road, shoulder, slope and outside of slope with roadside accumulated water, based on the change of temperature field control equation. This research showed that roadside accumulated water has a significant influence on the subgrade temperature field. The results showed the range of 0°C isotherm under the accumulated water was bigger than normal subgrade, and the depth of 0°C isotherm was deeper under the accumulated water than normal.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Kaoru Tachiiri ◽  
Xuanming Su ◽  
Ken’ichi Matsumoto

AbstractFor the purpose of identifying the key processes and sectors involved in the interaction between Earth and socio-economic systems, we review existing studies on those processes/sectors through which the climate impacts socio-economic systems, which then in turn affect the climate. For each process/sector, we review the direct physical and ecological impacts and, if available, the impact on the economy and greenhouse gas (GHG) emissions. Based on this review, land sector is identified as the process with the most significant impact on GHG emissions, while labor productivity has the largest impact on the gross domestic product (GDP). On the other hand, the energy sector, due to the increase in the demand for cooling, will have increased GHG emissions. Water resources, sea level rise, natural disasters, ecosystem services, and diseases also show the potential to have a significant influence on GHG emissions and GDP, although for most of these, a large effect was reported only by a limited number of studies. As a result, more studies are required to verify their influence in terms of feedbacks to the climate. In addition, although the economic damage arising from migration and conflict is uncertain, they should be treated as potentially damaging processes.


Atmosphere ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 707
Author(s):  
Petros Vasilakos ◽  
Yongtao Hu ◽  
Armistead Russell ◽  
Athanasios Nenes

Formation of aerosol from biogenic hydrocarbons relies heavily on anthropogenic emissions since they control the availability of species such as sulfate and nitrate, and through them, aerosol acidity (pH). To elucidate the role that acidity and emissions play in regulating Secondary Organic Aerosol (SOA), we utilize the 2013 Southern Oxidant and Aerosol Study (SOAS) dataset to enhance the extensive mechanism of isoprene epoxydiol (IEPOX)-mediated SOA formation implemented in the Community Multiscale Air Quality (CMAQ) model (Pye et al., 2013), which was then used to investigate the impact of potential future emission controls on IEPOX OA. We found that the Henry’s law coefficient for IEPOX was the most impactful parameter that controls aqueous isoprene OA products, and a value of 1.9 × 107 M atm−1 provides the best agreement with measurements. Non-volatile cations (NVCs) were found in higher-than-expected quantities in CMAQ and exerted a significant influence on IEPOX OA by reducing its production by as much as 30% when present. Consistent with previous literature, a strong correlation of isoprene OA with sulfate, and little correlation with acidity or liquid water content, was found. Future reductions in SO2 emissions are found to not affect this correlation and generally act to increase the sensitivity of IEPOX OA to sulfate, even in extreme cases.


Author(s):  
J. Sans ◽  
M. Resmini ◽  
J.-F. Brouckaert ◽  
S. Hiernaux

Solidity in compressors is defined as the ratio of the aerodynamic chord over the peripheral distance between two adjacent blades, the pitch. This parameter is simply the inverse of the pitch-to-chord ratio generally used in turbines. Solidity must be selected at the earliest design phase, i.e. at the level of the meridional design and represents a crucial step in the whole design process. Most of the existing studies on this topic rely on low-speed compressor cascade correlations from Carter or Lieblein. The aim of this work is to update those correlations for state-of-the-art controlled diffusion blades, and extend their application to high Mach number flow regimes more typical of modern compressors. Another objective is also to improve the physical understanding of the solidity effect on compressor performance and stability. A numerical investigation has been performed using the commercial software FINE/Turbo. Two different blade profiles were selected and investigated in the compressible flow regime as an extension to the low-speed data on which the correlations are based. The first cascade uses a standard double circular arc profile, extensively referenced in the literature, while the second configuration uses a state-of-the-art CDB, representative of low pressure compressor stator mid-span profile. Both profiles have been designed with the same inlet and outlet metal angles and the same maximum thickness but the camber and thickness distributions, the stagger angle and the leading edge geometry of the CDB have been optimized. The determination of minimum loss, optimum incidence and deviation is addressed and compared with existing correlations for both configurations and various Mach numbers that have been selected in order to match typical booster stall and choke operating conditions. The emphasis is set on the minimum loss performance at mid-span. The impact of the solidity on the operating range and the stability of the cascade are also studied.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Marshal Thakran ◽  
Meenakshi ◽  
Jitender Sharma ◽  
Charles Gilbert Martin

Purpose The purpose of this paper is to evaluate the model of a rear pressure bulkhead with different design optimizations to meet the pressurized cabin requirements of an aircraft. Design/methodology/approach This paper presents the results of the static analysis of a dome-shaped rear pressure bulkhead model designed in Catia-v5. Numerical analysis of model meshed in hyper-mesh and solved using Opti-Struct for iterative design optimizations. Findings All the iterative models are analyzed at 9 Psi. Rear pressure bulkhead designed with L-section stringer shows better results than the model optimized with T-section stringer for the same thickness. The model optimized with L-shaped stinger also reduces the weight of the bulkhead without affecting the structural integrity. Practical implications It has been concluded in this paper that the selection of specific shapes of the stringers shows a significant influence on weight reduction. Originality/value This paper provides a topical, technical insight into the design and development of a rear pressure bulkhead. It also outlines the future development of dome-shaped rear pressure bulkhead.


2000 ◽  
Author(s):  
Zheji Liu ◽  
D. Lee Hill ◽  
Yuri I. Biba

Abstract An extensive investigation surrounding a performance shortfall of a pipeline compressor is presented. Regions of high aerodynamic loss are identified from an extensive flange-to-flange numerical investigation. Special attention is placed on understanding the impact of the interface model between the rotating and stationary components on the performance of each individual component and the whole machine. This process lead to the redesign of the radial inlet, the diffuser region, and the volute. Upon numerical validation of the proposed design changes, the components were manufactured and installed into the compressor that was already operating in the field. “Field” testing showed the new design to have a peak efficiency improvement of 4 points surpassing the contract guarantee.


2017 ◽  
Vol 121 (1237) ◽  
pp. 287-319 ◽  
Author(s):  
E. R. Galea ◽  
Z. Wang ◽  
F. Jia

ABSTRACTIn this paper, fire and evacuation computer simulations are used to reconstruct the 1985 Manchester Airport B737 fire that resulted in the loss of 55 lives. First the actual fire and evacuation are reconstructed. Secondly, the impact of exit opening times and external wind on the fire and evacuation are investigated. Finally, the potential benefit offered by modern materials is evaluated. The results suggest that the number of fatalities could have been reduced by 87% had the forward right exit not malfunctioned and by 36% had the right over-wing exit been opened without delay. Furthermore, given the fuel pool size and location, a critical wind speed of 1.5m/s is necessary to cause the fire plume to lean onto the fuselage eventually resulting in fuselage burn-through. Finally, it is suggested that the use of modern cabin materials could have made a significant difference to the fire development and survivability.


2013 ◽  
Vol 18 (3) ◽  
pp. 381-394 ◽  
Author(s):  
Long Yu ◽  
Martin Greve ◽  
Markus Druckenbrod ◽  
Moustafa Abdel-Maksoud

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