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1

Pomiary gęstego aerozolu oleju rzepakowego za pomocą fazowej anemometrii dopplerowskiej

Bialkowski M. T., Pekdemir T., Brautsch M., Towers D. P., Elsbett G.

Silniki Spalinowe

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2005

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R. 44, nr 4

41--50

PL

Strugi gęstego oleju rzepakowego (RSO) rozpylone pod wysokim ciśnieniem zostały przebadano metodą fazowej anemometrii dopplerowskiej (PDA). Próbki zimnego sprężonego oleju były wstępnie ogrzewane i wtryskiwane pod różnym ciśnieniem (56,3; 76,0; 93,8; 112,5; 131,3 MPa) do ośrodka o sześciu różnych gęstościach (3; 6; 15; 30; 45; 60 kg/m3). Duża gęstość RSO w istotnym stopniu oddziałuje na jakość pomiaru rozmiarów kropli i prowadzi do podobnych trudności na jakie napotkano podczas badań gęstego aerozolu oleju napędowego. Testy rozmiarów kropel wymagały analizy wpływu napięcia fotopowielacza (PMT) oraz warunków wtrysku na określenie wielkości kropli. Dla prowadzonych badań najodpowiedniejsza czułość PMT została określona przy 1000 V. Rozkład rozmiarów kropel wykazał, że wzrost ciśnienia otoczenia skutkuje deformacją Gaussowskiego rozkładu wymiarów kropli przez przyrost liczby kropel o małych wymiarach. Ponadto, wzrost zarówno ciśnienia wtrysku, jak i ciśnienia ośrodka powoduje zmniejszenie średniej średnicy kropli oraz wyraźny spadek liczby uwzględnianych kropel. Mimo trudności z zastosowaniem techniki PDA do badań aerozolu RSO można wysnuć wniosek, że metoda może być z powodzeniem stosowana, pod warunkiem odpowiedniego dostosowania parametrów PDA.

EN

High pressure, dense rapeseed oil (RSO) sprays have been investigated using a Phase Doppler Anemometry (PDA) setup. Samples of cold pressed RSO were pre-heated and injected at various pressures (56.3, 76.0, 93.8,112.5,131.3 MPa) and six different ambient densities (3,6,15,30,45,60 kg/m3). High density of RSO significantly affects the quality of sizing measurements, and leads to the similar experimental problems which have been found for the dense Diesel spray. The sizing tests involved analysis of the influence of the photomultiplier (PMT) voltage and injection conditions on droplet validation. The sensitivity of the PMT at 1000 V was found as the most appropriate in the performed tests. The droplet size distributions revealed that the increasing ambient pressure results in a deformed Gaussian drop size distribution having larger number of small droplets. Furthermore, the increasing injection and ambient pressures lower the mean droplet diameter but result in the significant decrease of the droplet validation. Despite the experimental difficulties of applying the PDA technique to RSO sprays it is concluded the method can be successfully used if the appropriate adjustment of PDA parameters is undertaken.

2

Preliminary approach towards a CDI system modification operating on neat rapeseed oil

Bialkowski M. T., Pekdemir T., Reuben R., Brautsch M., Towers D. P., Elsbett G.

Journal of KONES

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2005

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Vol. 12, No. 1-2

31-42

EN

A Common-rail Diesel Injection (CDI) Bosch system was modified to operate on neat rapeseed oil (RSO) in a single tank mode. The performed modifications were derived from the fundamental and comparative injection studies. Laser droplet sizing, high-speed imaging and the Acoustic Emission (AE) tests combined with the basic bench scale experiments were employed to define the main direction of modifications. The RSO pre-heating was found as the most feasible direction of the modification. Some technical constrains were taken into account prior to the modification. The paper indicates on the main direction of the modification and evaluates the preliminary results of the CDI engine tests. Cold start, deposit formation, engine oil deterioration and drivability of a Mercedes Benz 220 C-class car had been investigated to assess the modification. The injection system did not exhibit the same magnitude of undesired effects as previously recorded in similar test with DI Diesel engines. A long-term drive tests provided very promising results on which further modification could be based. The engine test and inspection revealed that RSO pre-heating of successfully alters its properties enabling its successful use in a CDI system.

3

Effect of fuel temperature and ambient pressure on a common rail rapeseed oil spray

Bialkowski M. T., Pekdemir T., Towers D. P., Reuben R., Brautsch M., Elsbett G.

Journal of KONES

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2004

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Vol. 11, No. 1-2

53-65

EN

This paper investigated spray characteristics of rapeseed oil (RSO) as renewable fuel for common-rail (OR.) diesel engines using high-speed camera image technique and Phase Doppler Anemometry (PDA). Experimental spray penetration at various injection pressures and fuel temperatures for RSO were compared with data of standard oil (SO) taken at the same varying ambient conditions. Additionally. corresponding to penetration data, data sets of spray development for these two oils were also aquired. It has been found that RSO temperature of 60 graduate C being used in practice to preheat plant oils in modified OR, engines does not improve spray penetration to be sufficient to reach the penetration equivalent at 25 graduate C for SO. It is concluded that producing RSO spray similar to SO one recquires high injection pressure and fuel temperature, and the pressure effect is more influential. The PDA measurements revealed stronger injection pressure effect on values of Ds2 and DID than oil temperature.