Determination of Optimum Heat Transfer Area for Vacuum Evaporators in Ships

2004 ◽  
Vol 41 (01) ◽  
pp. 17-21
Author(s):  
Recep Ozturk ◽  
Ahmet Dursun Alkan
Keyword(s):  
Heat Transfer ◽  
Thermodynamic Analysis ◽  
Analytical Method ◽  
Load Capacity ◽  
Design Parameters ◽  
Heat Transfer Area ◽  
Optimum Heat ◽  
Definition Of ◽  
Significant Factors

In ships, utility water can be produced from seawater through a vacuum evaporator instead of supplying from ports, and this solution will certainly allow extra load capacity for ships. In this application, the size of vacuum evaporators and their heat transfer areas are significant factors in terms of investment costs and the volume or weight capacity, which for ships are particularly important parameters. In the present research, the change of heat transfer areas of vacuum evaporators that are used to produce utility water was analyzed with respect to design parameters and the results from the thermodynamic analysis were evaluated to define the optimum heat transfer area. Because an analytical method has been employed in the definition of the optimum heat transfer area, the influence of design parameters on the evaporatorsize can be identified easily.

The Energy-Saving Optimization of the Organic Heat Transfer Material Heater

2012 ◽  
Vol 455-456 ◽  
pp. 284-288
Author(s):  
Wei Li Gu ◽  
Jian Xiang Liu
Keyword(s):  
Heat Transfer ◽  
Energy Saving ◽  
Flue Gas ◽  
Theoretical Basis ◽  
Operation Management ◽  
Exergy Loss ◽  
Irreversible Processes ◽  
Design Parameters ◽  
Gas Temperature

this paper studies the typical irreversible processes such as combustion and heat transfer with temperature difference based on the theory of thermodynamics, analyzes the influencing factors on exergy loss in irreversible processes, on the basis of this analysis, proposes the energy-saving optimization measures on design and operation management of the organic heat transfer material heater, and specially points out that in the design process, objective function can be constructed with the exergy loss as evaluation index to determine the outlet flue gas temperature of furnace and the flue gas temperature, and provides theoretical basis for the determination of design parameters.

Design for static stiffness of hydrostatic bearings: double-action variable compensation of membrane-type restrictors and self-compensation

2014 ◽  
Vol 66 (2) ◽  
pp. 322-334 ◽  
Author(s):  
Yuan Kang ◽  
De-Xing Peng ◽  
Yu-Hong Hung ◽  
Sheng-Yan Hu ◽  
Chorng-Shyan Lin
Keyword(s):  
Load Capacity ◽  
Pressure Ratio ◽  
Design Parameters ◽  
Static Stiffness ◽  
Content Type ◽  
Hydrostatic Bearings ◽  
Closed Type ◽  
Maximum Stiffness ◽  
Membrane Type

Purpose – This article is the fourth part of a serial studies about constant and variable compensations of the closed-type hydrostatic plane-pad bearing, which is presented for the double-action membrane-type restrictor and self-type compensation. The paper aims to discuss these issues. Design/methodology/approach – The load capacity and static stiffness in thrust direction of the planar bearing is determined by the flow continuity equation which belongs to the same approaches as shown in previous parts of this serial studies. Findings – The results reveal that the appropriate range of recess pressure ratio and design parameters of bearing and restrictor for the infinite or maximum stiffness can be obtained. Also, the influence of design parameters on negative stiffness that should be avoided in bearing design is revealed in detail. Originality/value – The determination of design parameters of a double-action membrane-type restrictor can be yielded from finding results of this study for maximum stiffness in design of hydrostatic bearings.

scholarly journals A non-field analytical method for heat transfer problems through a moving boundary

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vladimir Kulish ◽  
Vladimír Horák
Keyword(s):  
Heat Transfer ◽  
Chemical Reactions ◽  
Analytical Method ◽  
Moving Boundary ◽  
Front Propagation ◽  
Final Part ◽  
Important Type ◽  
Propagation Law ◽  
Transfer Problems

AbstractThis paper presents an extension of the non-field analytical method—known as the method of Kulish—to solving heat transfer problems in domains with a moving boundary. This is an important type of problems with various applications in different areas of science. Among these are heat transfer due to chemical reactions, ignition and explosions, combustion, and many others. The general form of the non-field solution has been obtained for the case of an arbitrarily moving boundary. After that some particular cases of the solution are considered. Among them are such cases as the boundary speed changing linearly, parabolically, exponentially, and polynomially. Whenever possible, the solutions thus obtained have been compared with known solutions. The final part of the paper is devoted to determination of the front propagation law in Stefan-type problems at large times. Asymptotic solutions have been found for several important cases of the front propagation.

Investigations in Hydrostatic Planar Bearings Compensated by Tapered-Spool Restrictors I: Flow Rate

2015 ◽  
Vol 32 (1) ◽  
pp. 63-69
Author(s):  
Y. Kang ◽  
H.-C. Cheng ◽  
C.-W. Lee ◽  
S.-Y. Hu
Keyword(s):  
Flow Rate ◽  
Analytical Method ◽  
Pressure Difference ◽  
Load Capacity ◽  
Design Parameters ◽  
Static Characteristics ◽  
Static Stiffness ◽  
Flow Rates ◽  
Single Action ◽  
Hydrostatic Bearing

ABSTRACTThis paper is former part of serial studies to investigate the influence of design parameters of tapered-spool type restrictors on static characteristics of hydrostatic bearing. The flow rates passing restrictors can determine the static characteristics of hydrostatic bearings. In this part an analytical method which includes formulas and solving is utilized to simulate dimensionless flow rate in both single-action and double-action tapered-spool restrictors. The numerical results illustrate the variations of flow rates with respect to the change of pressure and pressure difference, respectively. The findings give that the design parameters of tapered-spool restrictors and the useful range of recess pressure. The following part will depend on this paper results to study load capacity and static stiffness of hydrostatic bearing compensated by tapered-spool restrictor.

Determination of Flow Rate Characteristics of Pneumatic Solenoid Valves Using an Isothermal Chamber

2004 ◽  
Vol 126 (2) ◽  
pp. 273-279 ◽  
Author(s):  
Kenji Kawashima ◽  
Yukio Ishii ◽  
Tatsuya Funaki ◽  
Toshiharu Kagawa
Keyword(s):  
Heat Transfer ◽  
Critical Pressure ◽  
Pressure Ratio ◽  
Pressure Change ◽  
Pressure Response ◽  
Heat Transfer Area ◽  
New Methods ◽  
Upstream Pressure ◽  
Pneumatic Valves

In this paper, two new methods for obtaining the sonic conductance and the critical pressure ratio of pneumatic valves are proposed. Both methods use a chamber that can approximate isothermal conditions. This was achieved by filling the chamber with metal wire, which creates a larger heat transfer area and heat transfer coefficient. The sonic conductance and the critical pressure ratio are obtained by measuring the pressure in the chamber during charging and discharging. These methods take only seconds to perform and require less energy than the ISO 6358 procedure. The major factor in the error for the pressure response during the charging of the isothermal chamber is the upstream pressure change. Nevertheless, the sonic conductance can be determined within a 3% uncertainty. In addition, the sonic conductance calculated from the pressure response during the discharging of the chamber can be determined within a 1.2% uncertainty.

scholarly journals The numerical thermodynamic analysis of Otto-Miller Cycle (OMC)

2016 ◽  
Vol 20 (1) ◽  
pp. 363-369 ◽  
Author(s):  
Mehmet Cakir
Keyword(s):  
Heat Transfer ◽  
Thermodynamic Analysis ◽  
Design Parameters ◽  
Inlet Temperature ◽  
Miller Cycle ◽  
Dimensionless Form ◽  
Engine Design ◽  
Thermodynamic Performance ◽  
Compression And Expansion ◽  
Heat Transfer Effects

This paper presents a thermodynamic analysis for an irreversible Otto-Miller Cycle (OMC) by taking into consideration heat transfer effects and internal irreversibilities resulting from compression and expansion processes. In the analyses, the influences of the miller cycle ratio, combustion and heat loss constants and inlet temperature have been investigated relations with efficiency in dimensionless form. The dimensionless power output and power density and thermal efficiency relations have been computationally obtained versus the engine design parameters with respect to combustion and heat transfer constants. The results demonstrate that the heat transfer and combustion constants have considerable effects on the cycle thermodynamic performance. This situation theoretically verified for OMC.

scholarly journals THE PROCESS OF HEAT TRANSFER IN TWO-LAYERED CYLINDRICAL BODY

2019 ◽  
Vol 20 (11-12) ◽  
pp. 93-98
Author(s):  
U. V. Vidin ◽  
R. V. Kazakov ◽  
V. S. Zlobin
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Boundary Conditions ◽  
Analytical Method ◽  
Analytical Methods ◽  
Cylindrical Body ◽  
Characteristic Equations ◽  
The Third ◽  
Thermal Regimes

Determination of thermal regimes of composite cylindrical bodies by analytical methods leads to the appearance of complex characteristic equations, the solution of which is the determination of eigenvalues. The article considers a relatively simple approximate analytical method for determining the eigenvalues of characteristic equations for a two-layer cylindrical body under boundary conditions of the third kind. This method can also be easily used in more complex formulations of heat conduction problems.

scholarly journals A Non-Field Analytical Method for Heat Transfer Problems Through A Moving Boundary

2021 ◽  
Author(s):  
Vladimir Kulish ◽  
Vladimír Horák
Keyword(s):  
Heat Transfer ◽  
Chemical Reactions ◽  
Analytical Method ◽  
Moving Boundary ◽  
Front Propagation ◽  
Final Part ◽  
Important Type ◽  
Propagation Law ◽  
Transfer Problems

Abstract This paper presents an extension of the non-field analytical method – known as the method of Kulish – to solving heat transfer problems in domains with a moving boundary. This is an important type of problems with various applications in different areas of science. Among these are heat transfer due to chemical reactions, ignition and explosions, combustion, and many others. The general form of the non-field solution has been obtained for the case of an arbitrarily moving boundary. After that some particular cases of the solution are considered. Among them are such cases as the boundary speed changing linearly, parabolically, exponentially, and polynomially. Whenever possible, the solutions thus obtained have been compared with known solutions. The final part of the paper is devoted to determination of the front propagation law in Stefan-type problems at large times. Asymptotic solutions have been found for several important cases of the front propagation.

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