The design and analysis of pipe diffusers for centrifugal compressors

Bennett, I.J.; Tourlidakis, A.; Elder, R. L.

doi:10.1243/0957650001537886

Cited by 19 publications

(18 citation statements)

References 5 publications

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“…Oś dyfuzora rurkowego powinna być styczna do okrę-gu wierzchołków łopatek wirnika sprężarki odśrodkowej, tzn. okręgu zakreślo-nego promieniem R 2 [8][9][10]. Wejściowa przednia krawędź kanału dyfuzora rurkowego w rezultacie przenikania skośnego walcowego otworu gardzieli z cylindryczną powierzchnią wlotową dyfuzora o promieniu R 3 jest trójwymiarowa o zarysie elipsoidalnym (rys.…”

Section: Parametry Geometryczne Dyfuzora Rurkowegounclassified

“…Liczba kanałów dyfuzora rurkowego zawiera się zwykle w przedziale Z Dr = = 16÷34 [10,11,[14][15][16]. Przyjęcie liczby kanałów dyfuzora rurkowego Z Dr umożliwia wyznaczenie kolejnych parametrów geometrycznych, takich jak: 1) podziałka dyfuzora rurkowego na wlocie …”

Section: Parametry Geometryczne Dyfuzora Rurkowegounclassified

“…Zmniejszenie liczby dyfuzorów rurkowych przesuwa granicę pompażu w lewo, rozszerzając użyteczny zakres pracy sprężarki. Badania eksperymentalne autorów pracy [10] potwierdziły spostrzeżenie Japikse'a. W Instytucie Lotnictwa w Warszawie przeprowadzono także badania porównawcze osiągów dyfuzora rurkowego Vrany z cylindryczną częścią wlotową oraz zmodyfikowanego dyfuzora rurkowego z krzywoliniowym zarysem części wlotowej [13].…”

Section: Uwagi Końcoweunclassified

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Dyfuzor rurkowy sprężarki promieniowej i osiowo-promieniowej

Antas¹

2013

ZN PRz Mechanika

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DYFUZOR RURKOWY SPRĘŻARKI PROMIENIOWEJ I OSIOWO-PROMIENIOWEJNiskokosztowy dyfuzor rurkowy powstały w rezultacie wiercenia odrębnych kanałów został rozwinięty przez firmę Pratt & Whitney dla sprężarek promieniowych i osiowo-promieniowych o wysokiej sprawności. Wymienione oddzielne otwory wierconych kanałów są rozmieszczone w układzie symetrycznym, aby wzajemnie przecinały się w taki sposób, że oś dyfuzora rurkowego jest styczna do okręgu wierzchołków łopatek wirnika sprężarki odśrodkowej. W pracy przedstawiono oryginalną metodę obliczeń parametrów geometrycznych dyfuzora rurkowego oraz propozycję sposobu wyznaczenia parametrów strumienia na wylocie dyfuzora. Wymienione metody (zalecane do projektu koncepcyjnego sprężarki) oparto na twierdzeniu Pitagorasa, równaniu zachowania energii, równaniu ciągłości, pierwszej zasadzie termodynamiki, równaniu momentu ilości ruchu Eulera oraz definicjach stosowanych w teorii maszyn wirnikowych. Zaprezentowano także wyniki nielicznych badań eksperymentalnych tego dyfuzora.

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Section: Parametry Geometryczne Dyfuzora Rurkowegounclassified

Section: Uwagi Końcoweunclassified

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Dyfuzor rurkowy sprężarki promieniowej i osiowo-promieniowej

Antas¹

2013

ZN PRz Mechanika

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“…Compared with conventional vane island diffusers, the pipe diffuser has many advantages. Bennett et al (2000) point out that the pipe diffuser has higher stage efficiency and fewer friction losses. Moreover, the pipe diffuser is able to y  handle highly distorted inlet flow and gain superior performance at high inlet Mach numbers.…”

Section: Introductionmentioning

confidence: 95%

“…The pioneering researches by Kenny (1969Kenny ( , 1970Kenny ( & 1972 show that pipe diffusers have lower manufacturing cost, superior efficiency with supersonic inlet flow, and smaller throat blockage compared with alternative designs. The pipe diffuser has been applied in industrial products by General Electric and Pratt and Whitney in North America (Bennett et al 2000, Kenny 1972, and it is likely to play a more important role in compressors where the Mach number is high at the diffuser inlet (Kenny 1970, Zachau 2008). …”

Section: Introductionmentioning

confidence: 99%

Flow Characteristics of a Pipe Diffuser for Centrifugal Compressors

Sun¹,

Zheng²,

Linghu³

2017

JAFM

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The pipe diffuser, an efficient kind of radial bladed diffuser, is widely used in centrifugal compressors for gas turbine engines. This paper investigates flow characteristics of a pipe diffuser for centrifugal compressors by solving three-dimensional Reynolds-averaged Navier-Stokes equations. The results show that the pipe diffuser is adaptable to high Mach number incoming flows, and its unique leading edge could uniform the flow distortion. Numerical analysis indicates that the choke in pipe diffuser occurs suddenly, which leads to the dramatically steep performance curves near choke condition. Besides, it is found that the first half flow passage is particularly important to the pipe diffuser performance as it influences the choking behavior, the static pressure distribution, and the matching, so more attention should be paid to this region when designing or optimizing a pipe diffuser. Two counter-rotating vortices generated in the diffuser inlet region are captured by numerical simulation, and they can exist in the downstream of the diffuser passage. More detailed analysis show that these two vortices dominate the flow structure in the whole diffuser passage by shifting flow to certain positions and forming high-momentum flow cells and wake flow cells. The leading edge formed by the intersection of adjacent diffuser passages significantly affects this pair of vortices. In addition, these two vortices also affect the flow separation in pipe diffuser flow passages, they suppress separation near the front wall and back wall while facilitate separation at center locations. Therefore, it is recommended to design the leading edge of the pipe diffuser carefully to control the vortices and obtain a better flow field.

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Correlating Interfacial Moisture Content and Adhesive Fracture Energy of Polymer Coatings on Different Surfaces

2006

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Sn-Ag-Cu alloy. The Sn-Ag-Cu-Ge alloy solder ball had higher ball shear strength than the Sn-Ag-Cu alloy after an aging test at 150°C. The Sn-Ag-Cu-Ge alloy solder has better characteristics for both thermal oxidation and thermal reliability test. Therefore, it can be concluded that the Sn-Ag-Cu-Ge alloy is a good candidate to solve the oxidation problem, which is the most critical problem of the Pb-free solder. ExperimentalTwo solder ball compositions (in wt%) chosen in this study were : Sn3.0Ag0.5Cu and Sn3.0Ag0.5Cu0.05Ge, and had a diameter of 0.450 mm. The substrate used was CSP with 144 pad openings and each pad was 0.38 mm in diameter. The pads had an electroplated Ni/Au surface finish over Cu trace, with about 0.5 and 5.0 lm in thickness respectively. The solder balls from each composition were bonded to the CSP substrate using a water soluble flux under a reflow oven. The reflow condition is that preheating was done for 2 min at 150°C, the peak temperature was 235°C, and the dwell time was 60 sec.The solder balls after one were then analyzed or subjected to either multiple reflow up to 5 times or aging at 150°C for a duration up to 500 hs. XPS was utilized to check the oxide layer thickness and examine the surface chemical composition. We assumed that the oxide thickness can be defined by oxygen concentration under three atomic percent. The mechanical joint strength of the bonded balls was evaluated with Dage shear tester using a shear speed of 200 lm/s at a shear height of 10 lm.It is well known that ambient moisture and other environmental influences are detrimental to the adhesion of polymeric materials to metal surfaces. The primary reason why adhesion loss occurs is believed to be due to moisture accumulation at the polymer/metal interface. This is why adhesion loss does not generally correlate with the bulk moisture content of the polymer. In this work, we present measurements of the interfacial moisture content and adhesion for a series of polymer coatings having different surface chemistries. Measurements were made after reaching an apparent equilibrium in either a dry (0 % relative humidity) or wet (100 % relative humidity) environment. The loss of adhesion is found to correlate directly with interfacial water content. Surface treatments that resulted in a more hydrophilic surface lead to an increase in the interfacial water content and a decrease in interfacial fracture energy.Ambient moisture is well known to adversely affect the durability and performance of adhesive joints and coatings. [1] The interplay between the mechanical stress and chemical changes in the adhesive joint due to moisture adsorption is generally believed to be the root cause of failure of the adhesive application. Failure typically occurs at the polymer/metal interface, indicating that the primary mechanism for failure is not degradation of the bulk polymer. Instead, the structure of the coating near the interface is the determining factor in COMMUNICATIONS 114

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The design and analysis of pipe diffusers for centrifugal compressors

Cited by 19 publications

References 5 publications

Dyfuzor rurkowy sprężarki promieniowej i osiowo-promieniowej

Dyfuzor rurkowy sprężarki promieniowej i osiowo-promieniowej

Flow Characteristics of a Pipe Diffuser for Centrifugal Compressors

Correlating Interfacial Moisture Content and Adhesive Fracture Energy of Polymer Coatings on Different Surfaces

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