1,747,008 research outputs found
Low speed axial compressor design and evaluation : High speed representation and endwall flow control studies
No full textThis Thesis reports the design, build and test of two sets of blading for the
Cranfield University low speed research compressor. The first of these was a datum low
speed design based on the fourth stage of the DERA high speed research compressor
C 147. The emphasis of this datum design was on the high-to-low speed transformation
process and the evaluation of such a process through comparing detailed flow
measurements from both compressors.
Area traverse measurements in both the stationary and rotating frame of reference
were taken at Cranfield along with overall performance, blade surface static pressure and
flow visualisation measurements. These compare favourably with traverse and
performance measurements taken on C147 before commencement of the PhD work.
They show that despite the compromises made during the transformation process, due to
both geometric and aerodynamic considerations, both the primary and secondary flow
features can be successfully reproduced in the low speed environment.
The aim of the second design was to improve on the performance of the datum
blading through the use of advanced '3D' design concepts such as lean and sweep. The
blading used nominally the same blade sections as the datum, and parametric studies
were conducted into various lean/sweep configurations to try to optimise the blade
performance. The final blade geometry also incorporated leading edge recambering
towards the fixed endwalls of both the rotor and stator. The '3D' blading demonstrated a
1.5% increase in efficiency (over the datum blading) at design flow rising to around 3%
at near stall along with an improvement in stall margin and pressure rise characteristic.
The design work was completed using the TRANSCode flow solver for both the
blade-to-blade solutions (used in the SI-S2 datum design calculation) and the fully 3D
solutions (for the advanced design and post datum design appraisal). The 3D solutions
gave a reasonable representation of the mid-span and main 3D flow features but failed to
model the corner and tip clearance flow accurately. An interesting feature of the low
speed flowfield was the circumferential variation in total pressure observed at exit from
all rotors for both designs. This was not present at high speed and represents one of the
main differences between the high and low speed flow. Unsteady modelling of mid-
height sections from the first stage indicate that part of this variation is due to the
potential interaction of the rotor with the downstream stator while the remainder is due
to the wake structure from the upstream stator convecting through the rotor passage.
Finally, the implications for a high speed design based on the success of the 3D low
speed design are considered
Authors' attitudes to, and awareness and use of, a university institutional repository.
Full text linkThis article reports the findings of an author study at Cranfield University. The study investigated authors' publishing behaviours, attitudes, concerns, and their awareness and use of their institutional repository (IR), Cranfield QUEprints. The findings suggest that despite a reasonable amount of advocacy many authors had not heard of QUEprints and were not aware of its purpose. Once explained, all authors saw at least one benefit to depositing a copy of their work to QUEprints, but many were unsure how to deposit, preferring to depend on the Library to do the work. The authors voiced few concerns or conditions regarding the inclusion of their work in QUEprints, but felt that it would be an extra, inconvenient step in their workload. This research led to the development of the Embed Project which is investigating how to embed the IR into the research process and thereby encourage more authors to deposit their work
Controllability of road vehicles at the limits of tyre adhesion
Full text linkThe research project 'Controllability of Road Vehicles at the Limits of Tyre Adhesion'
(CROVLA) was established to investigate how tyre and chassis properties contribute
to the handling characteristics and stability of vehicles operating at or near to the limit
condition. The project involved the Department of Transport, SP Tyres UK Limited,
Jaguar Cars and Cranfield University.
An extensive proving ground test program of typical limit handling tests provided
characteristic driver input and vehicle response data for a variety of vehicle
configurations. The test data analysis was based on the concept of correlation. Cross-
correlation coefficients and average response time delays were obtained for various
pairs of quantities, namely steering angle and torque for the input and yaw rate and
lateral acceleration for the response. The predictability of the vehicle response was
evaluated by the rate by which the correlation coefficients change with severity.
Analogous to the proving ground work, vehicle dynamics simulations were carried
out. Two programs were employed to study the steady state performance and the
transient limit handling behaviour.
The `Steady State Cornering Model' was used to confirm some basic suspension
design rules established for optimising the lateral adhesion of a suspension design.
The importance of controlling camber and vehicle jacking by an appropriate
suspension design was identified.
A detailed vehicle model was built-up using the simulation code AUTOSIM. After
validating the model against proving ground data, some parametric studies were
conducted to quantify the effects of suspension and tyre properties on the transient
limit response behaviour.
Proving ground and simulation results suggest that response time lags and cross-
correlation coefficients in combination with other handling parameters can be used as
objective quality measures. The results quantified to what extent tyre and chassis
modifications change the limit handling behaviour
The effect of variations in relevance assessments in comparative experimental tests of index languages
No full textIt was desired to check whether the unexpected test results obtained in Cranfield II had been influenced by the relevance decisions. Three new sets of relevance decisions were therefore obtained, and the Cranfield II results were re-calculated for nineteen index languages on the basis of the new relevance judgements. A rank order of the index languages was found; in no case did the correlation co-efficient of any of the three new rank orders fall below 0.921 when compared with the original Cranfield II results.
The findings of a similar type of test by Lesk and Salton are considered, and the conclusion is reached that the results of Cranfield II had showed that the superiority of the single term index languages were not significantly affected by relevance judgements.Great Britain, Department of Education and Science, Office of Scientific and Technical Informatio
Proceedings of the Cranfield Multi-Strand Conference: Creating Wealth Through Research and Innovation (CMC 2008): 6-7 May 2008
No full textOrganised by: Cranfield UniversityThis new Multi-Strand Conference explored how wealth is created through research and innovation. It brought together researchers and practitioners from across the spectrum to discuss advances in applied sciences, engineering and technology, including associated management practices. There was a focus on application, especially in the environment sector, manufacturing, aerospace, health and defence sectors. A particular aim was to provide a welcoming and supportive forum for early-stage researchers to present and discuss their work with more established figures in their various fields.Sponsored by: Institution of Engineering and Technology (IET), Engineering and Physical Sciences Research Council (EPSRC), Institution of Mechanical Engineers (IMechE), British Computer Society (BCS), Advanced Institute of Management Research (AIM), Chartered Institution of Water and Environmental Management (CIWEM), Institute of Physics (IOP), Royal Aeronautical Society (RAeS), Innovative Manufacturing Research Centre (IMRC), Institution of Chemical Engineers (IChemE), Institute of Environmental Management and Assessment (IEMA
Technology Transfer for Development: Insights from the Introduction of Low Cost Water Well Drilling Technology to Uganda
Full text linkThird World development theory and practice are changing so rapidly that it is
important to critically examine the fashions of today before they become history. This
thesis considers the development, transfer, early adoption and sustainable use of
technology, coupled with private sector participation in rural water supply provision.
Improving water supplies for rural communities is one of the key challenges
faced by development interventionists today. Lack of low cost, off the shelf technology
for local enterprise which can provide affordable shallow wells for rural communities is
one barrier to facilitating improvements.
This thesis is based on research undertaken in Uganda to develop and transfer
low cost water drilling technology in the context of decentralisation and privatisation
policies. An extensive range of literature has been drawn together into 16 principles
which guide technology transfer and development intervention. These principles are reexamined
in the light of analysis of first hand experiences of undertaking a technology
transfer project and interviews with stakeholders regarding their attitudes and
perceptions.
The research found that technology transfer is a cross-disciplinary and cross
cultural process in which the linkages between the technology, context, individuals,
organisations and beneficiaries need to be firmly established. Ugandan business and
local Government culture plays a major role in facilitating successful technology
uptake. Dealing with the risks associated with low cost groundwater technology is
fundamental for its wider adoption. The process of technology transfer is important,
particularly as high levels of stakeholder participation may compromise the delivery of
outputs, at least in the short term.
In terms of future challenges, this thesis shows that, culture, governance and
equity need to be closely examined in relation to private sector participation in rural
infrastructure provision. Private sector participation can conflict with community
participation. How to adequately support innovation in Sub-Saharan Africa while
harmonising development interventions is a challenge to the development community
Set-Based Concurrent Engineering Model for Automotive Electronic/Software Systems Development
Full text linkOrganised by: Cranfield UniversityThis paper is presenting a proposal of a novel approach to automotive electronic/software systems
development. It is based on the combination of Set-Based Concurrent Engineering, a Toyota approach to
product development, with the standard V-Model of software development. Automotive industry currently
faces the problem of growing complexity of electronic/software systems. This issue is especially visible at
the level of integration of these systems which is difficult and error-prone. The presented conceptual
proposal is to establish better processes that could handle the electronic/software systems design and
development in a more integrated and consistent manner.Mori Seiki – The Machine Tool Compan
Reducing deep soil compaction through strain modification under different wheel arrangements
No full textNew mechanisation methods associated with increasing loads have the potential to
cause undesirable deep compaction, which is difficult, expensive and in some cases
impossible to alleviate. Avoiding or reducing the risk of deep compaction seems to be
the most straightforward solution to compaction management.
Previous research indicates that some benefits can be achieved through interactions
between cultivation tines or other implements, in terms of the magnitude of forces and
the extent of soil deformation. Interaction within wheel arrangements could have
benefits for reducing deep soil compaction.
This study aimed to reduce the risk of deep soil deformation by locally modifying soil
conditions through interactions in order to increase soil resistance and hence load
support in the surface layers. To test the hypothesis, the research was based on soil
mechanics theories and failure mechanisms related to bearing capacity in order to
identify the major factors influencing load support and soil displacement. The nature
of soil failure patterns, interaction behaviour, soil deformation and load/sinkage
relationships were investigated under a wide range of dual and triple spaced
footings/wheels configurations. Small-scale tests using rectangular plates were firstly
conducted in a glass-sided tank. These initial tests were followed by larger-scale tests
in a soil bin and in the field under different soil conditions using actual wheels, spaced
and positioned as in the footing tests.
The results indicate that it is possible to reduce soil displacement at depth by
increasing load support in the soil surface layers through the interaction between
spaced wheel arrangements. It was shown that different interaction modes occurred
under dual configurations depending on the spacing between them. A locally
compacted zone was created between the wheels under dense interaction conditions,
increasing surface support. Surface support was increased further through a surcharging effect achieved by
placing a third footing/wheel between and higher than the side wheels (triple
arrangement). The central static interaction zone maximised the surface resistance
locally under these configurations. Although single wide section wheels such as Terra
tyres can tolerate higher loads at lower pressures, from a soil failure point of view,
this is usually associated with large active and passive failure zones inducing deeper
soil deformation. Triple spaced wheel arrangements with similar diameter wheels kept
soil displacements shallower whilst carrying a similar load to a single very wide
wheel with the same overall contact pressure. Reductions of up to 50% in the depth of
soil displacement were achieved with the triple arrangements for the same load. These
spaced arrangements can therefore be recommended as promising replacement for
single wide wheel under heavy machinery application in practical situations.
Benefits from the spaced arrangements are achieved in two ways: firstly by increasing
surface support through creating locally compacted zones and secondly by reducing
the size of active and passive failure zones causing shallower deformations.
Stony soils provide more surface support than stoneless soils and also non-uniform
soil with a denser layer at tillage depth can tolerate a greater load for a given sinkage
compared with uniform homogenous soil.
A mathematical model was developed to predict the vertical force under interacting
shallow footings and showed an acceptable level of agreement with the experimental
results. The model can be used to estimate the extent of the rupture distance of the
side passive planes to assist in identifying appropriate spacings and interaction modes
for spaced wheel arrangements
- …
