The Effect of Waves on Marine Propellers and Propulsion
Doctoral thesis
Permanent lenke
http://hdl.handle.net/11250/2443123Utgivelsesdato
2017Metadata
Vis full innførselSamlinger
- Institutt for marin teknikk [3397]
Sammendrag
Ship design is evolving around ever-increasing market demands in quest of competitive and cost-effective solutions. The global increase of shipping activities has raised concerns regarding the environmental impact of sea operations- transportation, fishing and exploitation of offshore resources. These conditions have driven naval architects to look for novel and energy efficient ship designs. Currently, there is increasing demand to optimize ships for actual environmental conditions i.e. in the presence of wind, waves, etc.
The work in this thesis explores the effect of waves on ship propulsion; it consists of two major parts. First, the analysis of propulsion system in the presence of waves where the effects of added resistance, wake variation, propulsion losses and propeller-engine interactions have been studied on engine efficiency, propulsion efficiency, power and RPM fluctuations in waves. It was found that the effect of waves on engine performance is relatively small, for the studied cases, however; wake variation and propulsion losses can cause considerable changes in vessel performance.
The second part deals with propeller performance in terms of cavitation, pressure pulses and efficiency in the presence of waves. The effects of wake change, speed loss, RPM variation and ship motions have been investigated. It was found that wake variations in waves has by far the largest impact on pressure pulses. Therefore, it is recommended to consider wake variation in waves while designing propellers. Due to the practical difficulties in doing this, which mainly are related to determining the wake variations, the recommended compromise is to consider the wake variation in one regular wave of length close to the ship length.
A framework of systematic analysis laid out in this thesis would be useful for analyzing different propulsion systems and propeller designs in the presence of waves. Methods and tools used in the work can be further incorporated into the optimization process to consider the effect of waves. The investigation in this thesis will help the optimization as various factors affecting the propulsion have been recognized and their effect has been quantified
Består av
Paper 1: Taskar, Bhushan; Steen, Sverre. Analysis of Propulsion Performance of KVLCC2 in Waves. I: Proceedings of the Fourth International Symposium on Marine Propulsors (Volume I). Texas: International Symposiums on Marine Propulsors 2015Paper 2: Taskar, Bhushan; Yum, Koosup; Pedersen, Eilif; Steen, Sverre. Dynamics of a Marine Propulsion System With a Diesel Engine and a Propeller Subject To Waves. I: Proceedings ASME 2015 34th International Conference on Ocean, Offshore and Arctic Engineering Volume 7: Ocean Engineering. - Is not included due to copyright available at http://dx.doi.org/10.1115/OMAE2015-41854
Paper 3: Taskar, Bhushan; Yum, Koosup; Steen, Sverre; Pedersen, Eilif. The effect of waves on engine-propeller dynamics and propulsion performance of ships. Ocean Engineering 2016 ;Volum 122. s. 262-277 https://doi.org/10.1016/j.oceaneng.2016.06.034
Paper 4: Taskar, Bhushan; Steen, Sverre; Bensow, Rickard E; Schröder, Björn. Effect of waves on cavitation and pressure pulses. Applied Ocean Research 2016 ;Volum 60. s. 61-74 https://doi.org/10.1016/j.apor.2016.08.009
Paper 5: Taskar B., Steen S., Eriksson J.,Effect of waves on cavitation and pressure pulses of a tanker with twin podded propulsion. © 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/