On the performance of a cascade of turbine rotor tip section blading in nucleating steam Part 3: Theoretical treatment

1997 ◽  
Vol 211 (3) ◽  
pp. 195-210 ◽  
Author(s):  
F Bakhtar ◽  
M R Mahpeykar
Keyword(s):  
Integral Method ◽  
Turbine Rotor ◽  
Main Flow ◽  
Theoretical Treatment ◽  
Viscous Effects ◽  
Mixture Formation ◽  
Two Phase ◽  
Time Marching ◽  
Phase Mixture ◽  
Improved Design

During the course of expansion in turbines, steam first supercools and then nucleates to become a two-phase mixture. Formation and subsequent behaviour of the liquid lower the performance of turbine wet stages. This is an area where greater understanding can lead to improved design. This paper describes the theoretical part of an investigation into nucleating flows of steam in a cascade of turbine rotor tip section blading. The main flow field is regarded as inviscid and treated by the time-marching technique modified to allow for two-phase effects. The viscous effects are assumed to be concentrated in boundary layers which are treated by the integral method. Comparisons are carried out with the experimental measurements presented in the earlier parts of the paper and the agreement obtained is good.

An Investigation of Nucleating Flows of Steam in a Cascade of Turbine Blading-Theoretical Treatment

1995 ◽  
Vol 117 (1) ◽  
pp. 138-144 ◽  
Author(s):  
F. Bakhtar ◽  
M. R. Mahpeykar ◽  
K. K. Abbas
Keyword(s):  
Flow Field ◽  
Surface Pressure ◽  
Integral Method ◽  
Main Flow ◽  
Theoretical Treatment ◽  
Viscous Effects ◽  
Pressure Distributions ◽  
Time Marching ◽  
Overall Efficiency ◽  
Turbine Blading

This paper describes the theoretical part of an investigation into nucleating flows of steam in a cascade turbine nozzle blading. The main flow field is regarded as inviscid and treated by the time-marching technique. The viscous effects are assumed to be concentrated in boundary layers which are treated by the integral method. The agreement obtained with the observed surface pressure distributions and overall efficiency measurements is very good.

On the Performance of a Cascade of Turbine Rotor Tip Section Blading in Nucleating Steam: Part 1: Surface Pressure Distributions

1995 ◽  
Vol 209 (2) ◽  
pp. 115-124 ◽  
Author(s):  
F Bakhtar ◽  
M Ebrahimi ◽  
R A Webb
Keyword(s):  
Surface Pressure ◽  
Turbine Rotor ◽  
Pressure Measurements ◽  
Flow Conditions ◽  
Mixture Formation ◽  
Two Phase ◽  
Blow Down ◽  
Pressure Distributions ◽  
Phase Mixture

During the course of expansion in turbines, steam first supercools and then nucleates to become a two-phase mixture. Formation and subsequent behaviour of the liquid lower the performance of turbine wet stages. To reproduce turbine nucleating and wet flow conditions requires a supply of supercooled steam which can be achieved under blow-down conditions by the equipment employed. The performance of a cascade of rotor tip section blading in nucleating steam has been studied. The results of the surface pressure measurements are described in the paper.

On the performance of a cascade of turbine rotor tip section blading in wet steam Part 3: Wake traverses

1997 ◽  
Vol 211 (8) ◽  
pp. 639-648 ◽  
Author(s):  
F Bakhtar ◽  
H Mashmoushy ◽  
O C Jadayel
Keyword(s):  
Liquid Phase ◽  
Two Phase Flow ◽  
Turbine Rotor ◽  
Phase Flow ◽  
Wet Steam ◽  
Flow Conditions ◽  
Two Phase ◽  
Blow Down ◽  
The Third ◽  
Phase Mixture

During the course of expansion of steam in turbines the fluid first supercools and then nucleates to become a two-phase mixture. The liquid phase consists of a large number of extremely small droplets which are difficult to generate except by nucleation. To reproduce turbine two-phase flow conditions requires a supply of supercooled vapour which can be achieved under blow-down conditions by the equipment employed. This paper is the third of a set describing an investigation into the performance of a cascade of rotor tip section profiles in wet steam and presents the results of the wake traverses.

On the performance of a cascade of turbine rotor tip section blading in wet steam Part 1: Generation of wet steam of prescribed droplet sizes

1997 ◽  
Vol 211 (7) ◽  
pp. 519-529 ◽  
Author(s):  
F Bakhtar ◽  
H Mashmoushy ◽  
J R Buckley
Keyword(s):  
Superheated Steam ◽  
Turbine Rotor ◽  
Phase Flow ◽  
Wet Steam ◽  
Flow Conditions ◽  
Two Phase ◽  
Lower Efficiency ◽  
Blow Down ◽  
Droplet Sizes ◽  
Phase Mixture

During the course of expansion in turbines steam nucleates to become a two-phase mixture consisting of a very large number of extremely small droplets carried by the vapour. Turbine stages operating in a two-phase regime have a lower efficiency than those working on superheated steam. To reproduce turbine two-phase flow conditions realistically requires a supply of supercooled steam which can be generated under blow-down conditions by the equipment employed. To generate wet steam the supercooled steam can be passed through a venturi. This paper is one of a set describing an investigation of the performance of a cascade of turbine rotor tip section profiles in wet steam and is concerned with the generation of a supply of wet steam of prescribed droplet sizes for admission to the cascade.

scholarly journals THE METHOD OF TWO-PHASE MIXTURE FORMATION IN THE AUTOMOTIVE DIESEL ENGINE AND THE DEVICE FOR ITS IMPLEMENTATION

2021 ◽  
Author(s):  
М.D. Dubin ◽  
◽  
М.V. Ryblov ◽  
Keyword(s):  
Diesel Engine ◽  
Fuel Economy ◽  
Intake Manifold ◽  
Second Phase ◽  
Power Capacity ◽  
Mixture Formation ◽  
Two Phase ◽  
Phase Mixture ◽  
Ecological Parameters ◽  
Engine Power

The article offers the method of improving of the automotive diesel engine power capacity, fuel economy and ecological parameters by two-phase mixture formation. In this way, the first phase is performed by means of the fuel activator supply (dose 10-20 %) into the intake manifold. The second phase is performed by means of the main fuel dose by the standard fuel system. The design of the developed system for the implementation of the first phase of two-phase mixture formation is described.

scholarly journals THE DEVELOPMENT OF ELECTRONIC CONTROL ALGORITHM OF FUEL ACTIVATOR INJECTION AT TWO-PHASE MIXTURE FOR-MATION IN AUTOMOTIVE DIESEL ENGINE

2021 ◽  
Author(s):  
М.V. Ryblov ◽  
◽  
М.D. Dubin ◽  
Keyword(s):  
Diesel Engine ◽  
Control Algorithm ◽  
Electronic Control Unit ◽  
Control Unit ◽  
Intake Manifold ◽  
Electronic Control ◽  
Mixture Formation ◽  
Two Phase ◽  
Intake Stroke ◽  
Phase Mixture

The article presents an algorithm of automatic control of injection of fuel activator supplied at the intake stroke into the intake manifold at two-phase mixture formation in the diesel engine. The algorithm represents a command set written in the microcontroller program of electronic control unit of the system performing the injection of fuel activator at the first phase of two-phase mixture formation.

On the performance of a cascade of turbine rotor tip section blading in wet steam Part 2: Surface pressure distributions

1997 ◽  
Vol 211 (7) ◽  
pp. 531-540 ◽  
Author(s):  
F Bakhtar ◽  
H Mashmoushy ◽  
O C Jadayel
Keyword(s):  
Droplet Size ◽  
Surface Pressure ◽  
Turbine Rotor ◽  
Pressure Measurements ◽  
Wet Steam ◽  
Flow Conditions ◽  
Two Phase ◽  
Blow Down ◽  
Pressure Distributions ◽  
Phase Mixture

In the course of expansion in turbines steam nucleates to become a two-phase mixture, the liquid consisting of a very large number of extremely small droplets carried by the vapour. Formation and subsequent behaviour of the liquid lowers the performance of turbine wet stages. To produce turbine nucleating and wet flow conditions realistically requires a supply of supercooled steam which can be achieved under blow-down conditions by the equipment employed. To obtain wet steam, the supercooled vapour generated is passed through a venturi before admission to the cascade. To evaluate the influence of droplet size two separate Venturis have been used in the investigation. The performance of a cascade of rotor tip section blading in wet steam has been studied. This paper is the second of a set and describes the results of the surface pressure measurements.

On the Performance of a Cascade of Turbine Rotor Tip Section Blading in Nucleating Steam: Part 2: Wake Traverses

1995 ◽  
Vol 209 (3) ◽  
pp. 169-177 ◽  
Author(s):  
F Bakhtar ◽  
M Ebrahimi ◽  
B O Bamkole
Keyword(s):  
Two Phase Flow ◽  
Turbine Rotor ◽  
Phase Flow ◽  
Flow Conditions ◽  
Two Phase ◽  
Blow Down ◽  
Phase Mixture

During the course of expansion of steam in turbines the fluid first supercools and then nucleates to become a two-phase mixture. To reproduce turbine two-phase flow conditions requires a supply of supercooled vapour which can be achieved under blow-down conditions by the equipment employed. This paper is the second of a set describing an investigation into the performance of a cascade of rotor tip section profiles in nucleating steam and presents the results of the wake traverses and droplet measurements.

On the Performance of a Cascade of Turbine Rotor Tip Section Blading in Wet Steam. Part 5: Theoretical Treatment

2006 ◽  
Vol 220 (4) ◽  
pp. 457-472 ◽  
Author(s):  
F Bakhtar ◽  
R J K Henson ◽  
H Mashmoushy
Keyword(s):  
Dominant Role ◽  
Electrical Power ◽  
Turbine Rotor ◽  
Experimental Results ◽  
Theoretical Treatment ◽  
Steam Turbines ◽  
Wet Steam ◽  
Economic Returns ◽  
Secondary Nucleation ◽  
Two Phase

During the course of expansion of steam in turbines, the fluid first supercools and then nucleates to become a two-phase mixture. The formation and behaviour of the liquid create problems that lower the performance of turbine wet stages and the mechanisms underlying these are insufficiently understood. Steam turbines play a dominant role in the generation of the main electrical power supply, and the economic returns on improved performance are substantial. This article is the last of a set and describes the theoretical part of an investigation into the performance of a turbine rotor tip section profile in wet steam. The experimental results are described in the earlier parts of the paper. To describe the behaviour of the flow theoretically, the conservation equations describing the main flow field are combined with equations describing droplet behaviour and the set is treated by the time-marching method. Comparisons are carried out with the experimental results presented in the earlier parts of the paper and the agreement obtained is good. When the droplets present in the steam are 0.15 μm in radius at inlet to the cascade, there is considerable secondary nucleation. With droplets of 0.05 μm radius, secondary nucleation is suppressed, but at high pressure ratios, the thermodynamic loss though reduced is not eliminated.

A study of the throughflow of nucleating steam in a turbine stage by a time-marching method

2013 ◽  
Vol 228 (5) ◽  
pp. 932-949 ◽  
Author(s):  
F Bakhtar ◽  
R Mohsin
Keyword(s):  
Nucleation And Growth ◽  
Steam Turbines ◽  
Turbine Stage ◽  
Two Phase ◽  
Droplet Nucleation ◽  
Direct Measurements ◽  
Time Marching ◽  
Phase Mixture ◽  
Marching Method ◽  
General Conservation

In the course of expansion in turbines, steam first supercools and then nucleates to become a two-phase mixture. The fluid then consists of a very large number of extremely small droplets which are carried by and interact with the parent vapour. The formation and subsequent behaviour of the liquid phase cause problems which lower the performance of the wet stages of steam turbines. To treat such flows the general conservation equations governing the whole field are combined with those describing droplet nucleation and growth and the set treated numerically. The article examines the solution of throughflows of nucleating steam in a turbine stage using a time-marching technique. The treatment which is the refinement of an earlier one has been applied to the flow in a turbine stage. Comparisons are presented between the results of theoretical solutions and direct measurements upstream and downstream of the nucleating stage and the agreement obtained is good.

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