tailieunhanh - Hydrodynamic Lubrication 2009 Part 12

Tham khảo tài liệu 'hydrodynamic lubrication 2009 part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Temperature Analyses of Circular Journal Bearings 191 speeds some other conditions are slightly different but are not significant . The operating conditions in Figs. b are respectively rotating speed N 1751 rpm 2502 rpm load on the journal P kN kN oil supply pressure Pin 98 kPa 98 kPa oil supply temperature Tin C C and ambient temperature Ta C and C. The bearing used was 3 bearing in both cases and the lubricating oil was transformer oil and 90 turbine oil. The eccentricity ratios were K and and the attitude angle was s 37 and 43 respectively. Fig. b. Temperature distribution in the middle section of the bearing metal 22 . a journal speed N 1751 rpm eccentricity ratio K and the attitude angle s 37 . b N 2502 rpm K s 43 192 8 Heat Generation and Temperature Rise Experimental isotherms and theoretical isotherms are in good agreement in both Figs. b. The highest temperature in the bearing metal appears slightly downstream of the minimum film thickness point in Fig. and a little further downstream in Fig. on the lubricating surface of the metal. The lowest temperature appears near the oil groove in both Figs. b. Figure shows calculated temperature distributions at the middle cross section of the oil film for peripheral velocities of U 10 m s and U 20 m s. The upper side of the rectangle corresponds to the journal surface and the lower side to the metal surface. The film thickness is very much exaggerated. The operating conditions other than those shown in the figure are the load on journal P1 kN the oil supply pressure pin 98 kPa the oil supply temperature T C ambient temperature Ta C and the bearing used is bearing 3. The figures show that the temperature distribution in the oil film is far from uniform. Comparison of Figs. b shows that the highest temperature in the oil film is higher in the case of higher peripheral speed the highest .