• 대한기계학회논문집
• /
• 제10권5호
• /
• pp.770-778
• /
• 1986

This paper is studied on the Junctiion of the large tank and the cylinderical outlet such as a pressure vessel attached a pipe or nozzle theoretically. It is assumed that the diameter of tank is much larger than that of the nozzle, so it can be approximated that nozzle is attached to plate. The analysis procedure can be viewed as the solution of interdependent subproblems: (a) the stress analysis of the cylinderical shell(nozzle), (b) the plane-stress analysis of the plate membrane problem, and (c) the analysis of the transverse bending deformation in the plate. On the procedure of (a), the Flugge formula are used, and the variables are the length and the ratio of the thickness to the radius of cylinderical shell. The solutions of thess problems are interrelated in the total solution through continuity and equilibrium conditions at the interface of middle planes of the plate and cylinderical shell.

• 한국산학기술학회논문지
• /
• 제10권1호
• /
• pp.46-51
• /
• 2009

본 논문은 세 개의 서로 다른 관수(9, 13 그리고 19)를 가지는 원통-판형 핀 관의 원통 측에서의 열전달 성능을 실험적 방법으로 평가하였다 관외를 흐르는 오일은 관내를 흐르는 냉각수에 의해 냉각된다. 오일 쿨러의 원통-다관형 열교환기는 단일 셀 통로와 두 개의 관 통로로 구성되며, 관 내경은 8.82mm, 관 길이는 575mm이다. 오일의 질량 유량은 $1.2{\sim}6.0m^3/h$이며, 냉각수의 질량 유량은 $0.6{\sim}3.0m^3/h$이다. 실험결과 9개의 관수를 가지는 열교환기의 총합 열전달계수는 13개와 19개의 관수의 열전달계수보다 각각 약 1.8배와 2.3배 높게 나타났다.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제10권2호
• /
• pp.141-152
• /
• 2018

The heating process such as line heating, triangular heating and so on is widely used in plate forming of shell plates found in bow and stern area of outer shell in a ship. Local shrinkage during heating process is main physical phenomenon used in plate forming process. As it is well appreciated, the heated plate undergoes the change in material and mechanical properties around heated area due to the harsh thermal process. It is, therefore, important to investigate the changes of physical and mechanical properties due to heating process in order to use them plate the design stage of shell plates. This study is concerned with the development of formula of plastic hardening constitutive equation for steel plate on which line heating is applied. In this study the stress correction formula for the heated plate has been developed based on the numerical simulation of tension test with varying plate thickness and heating speed through the regression analysis of multiple variable case. It has been seen the developed formula shows very good agreement with results of numerical simulation. This paper ends with usefulness of the present formula in examining the structural characteristic of ship's hull.

• 수산해양교육연구
• /
• 제19권1호
• /
• pp.129-136
• /
• 2007

The component parts of the shell plate of a ship are steel. but the screw propeller or the bow thruster is a compound of bronze, nickel and aluminum. On account of the these different components between metals of the shell plate, the screw propeller and the bow thruster, which are underwater, the shell plate of a ship is corroded by the action of ionization. Authors investigated the corrosion loss of the zinc anodes which were attached to the bottom shell of the training ship Kaya for about two years. The obtained results were as follows:1. In case of the shell plate the difference of the corrosion loss according to port and starboard was almost nothing. But the corrosion loss of the forward part was more than that of the aftward part.2. There was little difference in the corrosion loss between the forward and the aftward part on the bilge keel.3. The corrosion loss of the fore, midship and aft part on the false keel were 24.7%, 22.4% and 23.9% respectively.4. The corrosion loss of the fore and the aft part on the false keel was more than that of the midship part.5. The corrosion loss of the bow thruster was greater than any other parts.6. The nearer the zinc anode to the screw propeller the more the corrosion loss on the stern frame, and the situation was also same as on the rudder.

• 동력기계공학회지
• /
• 제15권3호
• /
• pp.25-30
• /
• 2011

A shell-and-tube oil cooler with plate fins was suggested to improve the defect of the conventional shell-and-tube oil cooler. Experiments were conducted to evaluate the heat transfer performance on the shell side of shell-and-plate finned tube oil cooler with three different tube numbers(9, 13 and 19). Oil flowing on the shell side was cooled by cold water flowing inside the tubes. A shell-and-tube heat exchanger of an oil cooler consisted of one shell pass and two tube passes with the inner tube diameter of 8.82 mm and the tube length of 575 mm. From the experiment of shell-and-tube oil cooler, it was found that the heat transfer coefficient of oil cooler with 9 tubes, as oil flow rate was increased, was approximately 140% and 250% higher than that of 13 and 19 tubes, respectively. The heat transfer coefficient at the water flow rate of $3m^3/h$, also was 120% and 140% higher than that of 2.4 and $1.8m^3/h$, respectively.

• International Journal of Air-Conditioning and Refrigeration
• /
• 제12권3호
• /
• pp.158-167
• /
• 2004

Condensation heat transfer experiments were conducted with a oblong shell and plate heat exchanger without oil in a refrigerant loop using R-134a. An experimental refrigerant loop has been developed to measure the condensation heat transfer coefficient $h_r$ and frictional pressure drop ${\Delta}p_f$ of R-134a in a vertical oblong shell and plate heat exchanger. Four vertical counter flow channels were formed in the oblong shell and plate heat exchanger by four plates having a corrugated sinusoid shape of a $45^{\circ}$ chevron angle. The effects of the refrigerant mass flux, average heat flux, refrigerant saturation temperature and vapor quality were explored in detail. Similar to the case of a plate heat exchanger, even at a very low Reynolds number, the flow in the oblong shell and plate heat exchanger remains turbulent. The results indicate that the condensation heat transfer coefficients and pressure drops increase with the vapor quality. A rise in the refrigerant mass flux causes an increase in the $h_r\;and\;{\Delta}p_f$. Also, a rise in the average heat flux causes an increase in the $h_r$. But the effect of the average heat flux does not show significant effect on the ${\Delta}p_f$. On the other hand, at a higher saturation temperature, both the $h_r\;and\;{\Delta}p_f$. found to be lower. Based on the present data, the empirical correlations are provided in terms of the Nusselt number and friction factor.

• Journal of Advanced Marine Engineering and Technology
• /
• 제25권6호
• /
• pp.1220-1227
• /
• 2001

The condensation pressure drop fur refrigerant R-22 flowing in the plate and shell heat exchanger were investigated experimentally in this study. Two vertical counterflow channels were formed in the exchanger by three plates of commercial geometry with a corrugated trapezoid shape of a chevron angel of $45^{\circ}$. The condensing R-22 flowing down in one channel exchanges heat with the cold water flowing up in the other channel. The effects of the mean vapor quality, mass flux, average imposed heat flux and system pressure of R-22 on the pressure drop were explored in detail. The quality change of R-22 between the inlet and outlet of the refrigerant channel ranges from 0.03 to 0.05. The present data showed that pressure drop increases with the vapor quality. At a higher mass flux, pressure drop is higher for the entire range of the vapor quality. Also, a rise in the average imposed heat flux causes an slight increase in the Pressure drop. Finally, at a higher system pressure the pressure drop is found to be slightly lower. Correlation is also provided for the measured pressure drops in terms of the friction factor.

• 대한기계학회논문집B
• /
• 제25권6호
• /
• pp.860-867
• /
• 2001

In this study, condensation heat transfer experiments were conducted with plate and shell heat exchangers(P&SHE) using R-22. An experimental refrigerant loop has been established to measure the condensation heat transfer coefficient of R-22 in a vertical P&SHE. Two vertical counter flow channels were formed in the P&SHE by three plates of geometry with a corrugated trapezoid shape of a chevron angle of 45°. Downflow of the condensing R-22 in one channel releases heat to the cold upflow of water in the other channel. The effect of the refrigerant mass flux, average heat flux, system pressure and vapor quality of R-22 on the measured data were explored in detail. The results indicate that at a higher vapor quality the condensation heat transfer coefficients are significantly higher. A rise in the refrigerant mass flux causes an increase in the h(sub)r. Also, a rise in the average heat flux causes an increase in the h(sub)r. Finally, at a higher system pressure the h(sub)r is found to be slightly lower. Correlation is also provided for the measured heat transfer coefficients in terms of the Nusselt number.

• 설비공학논문집
• /
• 제28권12호
• /
• pp.495-501
• /
• 2016

Condensation heat transfer and pressure drop of R245fa were investigated experimentally in a plate-shell heat exchanger which consisted of thirty seven counter flow channels formed by thirty-eight plates with a chevron angle of $50^{\circ}$. The upflow of the water in one channel receives heat from the downflow of R245fa in the other. The effects of refrigerant mass flux, imposed heat flux, refrigerant saturation pressure, and mean vapor quality on the heat transfer characteristics were explored in detail. Experimental correlations were proposed to predict the condensation heat transfer coefficient and friction factor in terms of the Boiling number, Reynolds number, and Prandtl number. In the experiments, the mean vapor quality in the refrigerant channel was varied from .22 to .82, mass flux from 3 to $5kg/m^2$, imposed heat flux from 1 to $3kW/m^2$, and system pressure from .61 to .81 MPa.

• 한국생산제조학회지
• /
• 제8권1호
• /
• pp.89-99
• /
• 1999

The automatic design of shell & tube type oil cooler can be used in real industrial environments. Since the automatic design system is intended to be used in small companies, it is designed to be operated well under environments of CAD package in the personal computer. It has adopted GUI in design system, and has employed DCl language. Design parameters to be considered in the design stage of shell and tube type oil cooler are type of oil cooler, outer diameter, thickness, length of tube, tube arrangement, tube pitch, flow rate, inlet and outlet temperature, physical properties, premissive pressure loss on both sides, type of baffle plate, baffle plate cutting ratio, clearance between baffle plate outer diameter and shell inner diameter and clearance between baffle plate holes. As a result, the automatic design system of shell & tube type oil cooler is constructed by the environment of CAD software using LISP. We have built database of design data for various kinds of shell & tube type oil coolers. The automatic design system have been assessed and compared with existing specification of design. Good agreement with Handbook of heat exchanger and design dta of real industrial environments has been found.