- TITLE:
PERFORMANCE EVALUATION OF LAMINAR FULLY DEVELOPED FLOW THROUGH TRAPEZOIDAL AND HEXAGONAL DUCTS SUBJECTED TO H1 BOUNDARY CONDITION. PART 1
- AUTHOR(S):
V. M. Petkov, V. D. Zimparov
- ABSTRACT:
Extended performance evaluation criteria (ExPEC) have been used to assess the performance characteristics of single-phase fully developed laminar flow through bundle of tubes with trapezoidal and hexagonal ducts. The bundle with circular tubes has been used as a reference heat transfer unit. The H1 boundary condition has been selected as thermal boundary condition. The performance characteristics
of the heat unit with non-circular tubes have been evaluated and compared to those of the reference unit for different objectives and constraints imposed. As a common constraint, the hydraulic diameter of the non-circular duct has been specified. The results showed that only in the case VG-2a the benefit can be obtained for the values of the irreversibility ratio.
- TITLE:
MOTION`S LAW OF MECHANISM REALIZED WINDING OF CONE COILS
- AUTHOR(S):
B. Stoyanov
- ABSTRACT:
This article discussed the law of motion of the ring rail of ring spinning machines. The mathematical law of motion for rising and lowering of ring rail is worked out. The problem of regular winding of spools with conical shape is discussed. An even distribution of yarnupon conical surface of spool is determinated with correction of the law of motion of ring rail.
- TITLE:
MATHEMATICAL MODELS OF MACHINING PARTS WITH COMPLICATED ROTATION FORM ON CNC MACHINES
- AUTHOR(S):
T. Kuzmanov, H. Metev, K. Krumov
- ABSTRACT:
MATHEMATICAL MODELS OF MACHINING PARTS WITH COMPLICATED ROTATION FORM ON CNC MACHINES
- TITLE:
INCREASE OF COMPACTNESS OF HYDROABRASIVE JET AND RELIABILITY OF CUTTING PROCESS WHILE USING FUNCTIONAL COATINGS ON JET ELEMENTS
- AUTHOR(S):
O. Salenko, V. Schetynin, M. Khorolska
- ABSTRACT:
В работе рассмотрены вопросы качества и надежности гидроабразивной обработки на основе повышения компактности гидроабразивной режущей струи за счет применения функциональных покрытий на струеформирующих елементах гидрорезной системы. Доказано повышение их работоспособности.
- TITLE:
DIMENSIONAL CHANGES DURING SINTERING OF IRON-CARBON POWDERS STRUCTURAL MATERIALS ALLOING WITH COPPER
- AUTHOR(S):
R. Maimarev, I. N. Mitev
- ABSTRACT:
DIMENSIONAL CHANGES DURING SINTERING OF IRON-CARBON POWDERS STRUCTURAL MATERIALS ALLOING WITH COPPER
