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A method for measuring Crank Angle resolved Thrust Loads
KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
2016 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

This thesis report elucidates the experimental and analytical methods of determining

the axial thrust loads of a twin scroll turbocharger mounted on a 6-cylinder

diesel engine, tested at Scania CV AB, Sodertalje. Literature survey revealed several

methods to experimentally determine the thrust loads but the concept of using

strain gauges was nally selected. The key objectives of this thesis are to determine

an experimental method to measure axial thrust loads, develop an analytical model

to predict axial loads and to perform a root cause analysis. It was noted that axial

load peaks are of immense interest here than the average values of the axial loads.

The method adopted to measure axial loads consists of a weakened bearing that

was capable of withstanding an estimated axial load and at the same time undergo

strains that could be sensed by strain gauges. The test operating points consisted

of a series of engine speeds and loads. Root cause analysis results suggested that

there was a minimal drift of 0.25 N force per 10 degree rise in temperature on the

bearings. Also, the main reason for the drift in strain gauge measurements was

the plastic deformation of the axial bearing that experienced higher axial loads due

to transient testing. A 1D model based on the Control Volume approach including

both the pressure and impulse contributions predicting the thrust loads was

modelled. The factored axial force measurements during most of the operating

conditions were negative (forces acting from the turbine towards the compressor)

with the highest value recorded as -90 N at 1400 rpm and 80 % engine load. The

highest factored axial force (negative) predicted by the model during the same operating

point was -100 N. The di erence between the predicted and measured max

load varied between 10 % to 15% among all the operating conditions considered

for correlation. It could be concluded that the experimental method established

could be used to measure axial loads. Further, future work in terms of non-invasive

measurements, CFD methods and usage of fast pressure sensors on compressor side

to predict transient conditions would improve the current method.

Abstract [sv]

Denna avhandling rapport belyser de experimentella och analytiska metoder for

att bestamma de axiella tryckbelastningar av en Twin Scroll turboaggregat monterat

paen 6-cylindrig dieselmotor, testas vid Scania CV AB, Sodertalje. Litteraturstudie

visade era metoder for att experimentellt bestamma axialbelastningar

men begreppet att anvanda tradtojningsgivare slutligen valts. De viktigaste mlen

for denna avhandling ar att bestamma en experimentell metod for att mata axiella

tryckbelastningar, utveckla en analytisk modell for att forutsaga axialbelastningar

och utfora en orsaksanalys. Det konstaterades att de axiella belastningstoppar ar

av stort intresse har an medelvardena for de axiella belastningar. Den metod som

for att mata axiella belastningar bestar av en forsvagad lager som kunde motstaen

uppskattad axiell belastning och samtidigt genomgar stammar som kan kannas av

tojningsgivare. Testdriftpunkter bestod av en serie av motorhastigheter och belastningar.

Rotfelsanalys resultat antydde att det fanns en minimal avdrift av 1N

kraft per 10 graders temperaturokning palagren. Aven den framsta orsaken till

drift i tradtojningsgivare matningar var plastisk deformation av det axiella lagret

som haft en hogre axiella belastningar pagrund av transient provning. En 1D modell

baserad pakontroll Volym tillvagagangssatt innefattande bade tryck och impuls

bidrag forutsaga axialbelastningar modellerades. De vgas axiella kraftmtningar under

strre delen av driftsfrhallandena var negativa (krafter som verkar fran turbinen

mot kompressorn) med det hogsta vardet registreras som -90 N vid 1400 rpm och

80 % motorbelastning. Den hogsta vagas axialkraften (negativ) forutsags av modellen

under samma arbetspunkt var -100 N. Skillnaden mellan forutsagelsen och

matning befanns variera mellan 10 % 15 % bland alla driftfrhallanden vagas for

korrelation. Det kan konstateras att den experimentella metod som faststallts kan

anvandas for att mata axiella belastningar. Vidare skulle det framtida arbetet i

termer av icke-invasiva matningar, CFD-modeller och anvandning av snabba trycksensorer

pakompressorsidan for att forutsaga transienta forhallanden forbattra den

nuvarande metoden.

Place, publisher, year, edition, pages
2016. , 118 p.
National Category
Mechanical Engineering
URN: urn:nbn:se:kth:diva-191490OAI: diva2:956810
External cooperation
Available from: 2016-08-31 Created: 2016-08-31 Last updated: 2016-09-05Bibliographically approved

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