Turbocharger Structural Integrity

Since the introduction of Euro VI in January 2014, all new diesel powered commercial vehicles have been equipped with turbocharged engines. It is virtually impossible to meet these emission regulations without using a turbocharger. Similarly, in the passenger car sector both on diesel and petrol (gasoline) powered vehicles, legislative pressure to reduce emissions of carbon dioxide are seeing the introduction of turbochargers across almost all new power units. Future legislation will continue this trend with engine manufacturers becoming increasingly reliant on turbocharging. As well as increasing the requirement for turbochargers, these external factors are also demanding that turbochargers become more responsive with reduced rotor inertia and lower thermal inertias. This in turn makes the task of ensuring that turbocharger components remain fit for purpose for the life of the turbocharger that much more difficult. In this paper some of the recent developments in turbocharger technology will be identified and the demands that these place on the structural components will be explored. The limitations of current methods of structural integrity assessment for some of these components will be discussed. Future developments of these methods will then be proposed

Active charge air cooling

Boosted IC engine development, both diesel and gasoline, is driving the need for better charge air temperature control. Charge air temperature directly and indirectly influences engine performance, fuel economy & emissions. To date charge air temperature control has, in the main, been passive; aiming only to reduce temperatures towards, but still above, ambient temperature. Driven by increasing specific output, the opportunities for sub-ambient charge cooling need to be investigated. For some real world driving conditions it is also desirable to raise the charge temperature. Air Cycle Technology ltd (ACT), working with the University of Huddersfield (UoH) are developing a controllable charge air cooling system, which will deliver charge air at sub-ambient temperature over a wide engine operating range. The system uses a turbo-expander to deliver air-cycle cooling in a simple and practical way. The system can be enhanced by combination with a charge air heating process. Accurate charge temperature control over as wide an engine operating range as possible is also addressed. The system is fully compatible with the operational, packaging and cost needs of vehicle OEMs. The paper presents the principle, process and application of a controllable charge air cooling/heating system. It covers the design and operation of the turbo-expander which delivers sub-ambient charge temperatures, the option of charge air heating and possible control methods. Examples of specific engine applications are presented to clearly indicate the opportunities for improvements in engine performance and fuel economy

The Impediments to Nigeria Understanding Oil Production Volumes, Losses and Potential Solutions

The issue of the quantity of oil produced or missing has traditionally been played down in Nigeria. This is evident as no one in or outside Nigeria is able to quote a totally reliable production volume or loss figure. The aim of this study is thus to search for the root causes as to why there are difficulties in ascertaining the quantity of crude oil produced or missing per day and for potential solutions. The research assesses the present situation and problems requiring solution concerning Nigerian oil and gas measurement control. This is achieved through an intensive review of each of the notified bodies responsible for Nigeria’s oil and gas measurement control, using secondary resources. The bodies reviewed in this study are the Department of Petroleum Resources and the Weights and Measures Department. The study has identified knowledge impediments among the designated bodies. Also discovered were inadequate measurement equipment and absence of measurement guidelines, thus, no mechanisms were in place to address any mismeasurements or losses that are discovered. Provision of comprehensive training to the regulatory body to provide it with the necessary “teeth” to ensure effective delivery of it regulatory function has therefore been recommended as the key solution

Graphene Enhanced Adsorption Desalination System

Currently almost one billion people across the world have no access to a safe potable drinking water. According to UN statistics, by 2030 the water demand will exceed the supply by 40%. This means that up to two-third of the world’s inhabited areas would be water stressed. There are currently no commercially available small scale water desalination / purification units that could serve small communities with critical needs for potable water. Most desalination and purification units are centralized and consume a large amount of energy which contributes to the overall carbon footprint. The research questions to be addressed by this project are: 1) Can new adsorbent systems be developed to allow efficient use of low grade energy for water desalination? 2) Can the technology be reduced in size of water desalination / purification units that to allow deployment on a small localised scale? 3) Could such a system utilise low grade, waste or renewable energy resources for a more sustainable environment? 4) How can sustainable water desalination units be produced that serve small communities at minimum installation and operational cost

Effects of ported shroud casing treatment on the acoustic and flow behaviour of a centrifugal compressor

[EN] Centrifugal turbomachines of smaller sizes operating at higher speeds have become pervasive due to the increased specific power and reliability achieved by improvements in manufacturing, materials and computational methods. The presence of these small turbomachines, specifically compressors, in helicopters, unmanned aerial vehicles (UAVs), auxiliary power units (APUs), turbochargers and micro gas turbines necessitates superior aerodynamic performance over a broad operational range which is widely achieved by ported shroud casing designs. In addition to aerodynamic performance, acoustic emissions have become a critical aspect of design for these small centrifugal compressors due to high operational speeds. Furthermore, the literature on the acoustic effects of the casing treatment is rather limited. Therefore, the impact of ported shroud casing treatment on the acoustic and flow features of the compressor operating at the design and near surge conditions have been quantified by numerically modelling the open and blocked configuration of the compressors. Upon comparing with experimental results, the numerical spectra are shown to capture the differences between the two configurations at the investigated operating points with reasonable accuracy. Although the casing treatment is generally seen to decrease the overall acoustic emission of the compressor at both operating conditions, increased propagation of tonal content in the direction upstream to the impeller is observed, particularly for design operation. Broadband characteristics in the lower and medium frequency regions usually associated with near surge operation including `whoosh' noise are observed to be alleviated by the ported shroud casing treatment.The author(s) disclosed receipt of the following financial support for the research, authorship and/or publication of this article: The project is sponsored and supported by BorgWarner Turbo Systems and the Regional Growth Fund (RGF Grant Award 01.09.07.01/1789C).Sharma, S.; Garcia Tiscar, J.; Allport, JM.; Barrans, S.; Nickson, AK. (2020). Effects of ported shroud casing treatment on the acoustic and flow behaviour of a centrifugal compressor. International Journal of Engine Research. 21(6):998-1011. https://doi.org/10.1177/1468087419880431S998101121

Acoustic characterisation of a small high-speed centrifugal compressor with casing treatment: an experimental study

[EN] With the advancements in manufacturing, materials and computational methods, turbomachinery designs have become more efficient providing higher specific power and reliability with lower weight and cost. The rotational speed of turbomachines has increased while the overall machine size has decreased for a similar power output leading to the pervasive presence of small, high-speed turbomachines, specifically centrifugal compressors in helicopters, unmanned aerial vehicles (UAVs), auxiliary power units (APUs), turbochargers and micro gas turbines. In addition to superior aerodynamic performance over a wide range, increased operating speeds have made the acoustic emissions of small centrifugal compressors a critical aspect of design. Therefore, this work presents an experimental campaign to characterise the acoustic behaviour of a compressor with an intent to quantify the dominant features of the flow-induced noise for design and near surge operating conditions. Furthermore, the campaign is extended to establish the impact of the ported shroud casing treatment and operating speed on the acoustic emission of the compressor. The in-duct noise measurement method is used in this work to quantify the noise generated in the compressor by measuring pressure fluctuations near the inducer and diffuser while the propagation of the generated noise to the ducts is computed from an array of piezoelectric sensors. Spectra at the design operating point are dominated by tonal noise while broadband noise content is the dominant feature of spectra for near surge operation. Although the ported shroud cavity does not significantly alter the overall noise levels of the compressor operating at design condition, it does seem to propagate tonal noise. For near surge operation, the casing treatment positively impacts the acoustic emission with a reduction of approximately 10 dB in the range up to the blade pass frequency. Furthermore, various broadband features are also observed to be alleviated by the casing treatment. (C) 2019 Elsevier Masson SAS. All rightsThe project was sponsored and supported by BorgWarner Turbo Systems and the Regional Growth Fund (RGF Grant Award 01.09.07.01/1789C). The authors would like to thank BorgWarner Turbo Systems for permission to publish the results presented in this paper.Sharma, S.; Broatch, A.; Garcia Tiscar, J.; Allport, JM.; Nickson, AK. (2019). Acoustic characterisation of a small high-speed centrifugal compressor with casing treatment: an experimental study. Aerospace Science and Technology. 95:1-15. https://doi.org/10.1016/j.ast.2019.1055181159