Modeling and Performance Analysis of AC Plant Heat Exchanger

AC plant Chiller is considered as a shell-and-tube heat exchanger and generally applied in a water-cooled chiller. These days shell and tube heat exchanger (STHX) is the most common type of heat exchanger broadly used in marine ships, due to its high pressure application. The AC plants fitted on-board Marine ships consist of a Chiller i.e. parallel flow heat exchanger with baffles. It is important to improve the performance of a chiller so that the usage of electrical energy can be reduced while the quality of a product can be increased. The water is cooled by using refrigerant in this chiller. This project mainly deals with modeling the prototype of basic geometry of shell and tube heat exchanger using Solidworks and meshing using simulation run using CFD package ANSYS. In this paper, by varying the number of baffles and different fluids they are water, R134a and R410a their performance of the chiller is studied. In this work, effect of the baffle spacing on the performance of a heat exchanger has been examined. Thermal and fatigue analysis is done in ANSYS for two materials Aluminum and Copper for better fluid at from CFD analysis.

Sediment metals adhering to biochar enhanced phosphorus adsorption in sediment capping

Metal ions in sediment were inherent Ca and Fe sources for biochar modification. In this work, effect of Ca2+ and Fe2+ released from sediment on biochar for phosphorus adsorption was evaluated. Results showed that, raw peanut shell biochar (PSB) was poor in phosphorus adsorption (0.48 mg/g); sediment-triggered biochar (S-PSB) exhibited P adsorption capacity of 1.32 mg/g in capping reactor and maximum adsorption capacity of 10.72 mg/g in Langmuir model. Sediment released Ca2+ of 2.2–4.1 mg/L and Fe2+/Fe3+ of 0.2–9.0 mg/L. The metals loaded onto biochar surface in the forms of Ca-O and Fe-O, with Ca and Fe content of 1.47 and 0.29%, respectively. Sediment metals made point of zero charge (pHpzc) of biochar shifted from 5.39 to 6.46. The mechanisms of enhanced P adsorption by S-PSB were surface complexation of CaHPO4 followed by precipitation of Ca3(PO4)2 and Ca5(PO4)3(OH). Sediment metals induced modification of biochar and improvement of P adsorption, which was feasible to overcome the shortcomings of biochar on phosphorus control in sediment capping.

Numerical analysis of free convection from a spinning cone with variable wall temperature and pressure work effect using MD-BSQLM

The problem of the numerical analysis of natural convection from a spinning cone with variable wall temperature, viscous dissipation and pressure work effect is studied. The numerical method used is based on the spectral analysis. The method used to solve the system of partial differential equations is the multi-domain bivariate spectral quasi-linearization method (MD-BSQLM). The numerical method is compared with other methods in the literature, and the results show that the MD-BSQLM is robust and accurate. The method is also stable for large parameters. The numerical errors do not deteriorate with increasing iterations for different values of all parameters. The numerical error size is of the order of 1 0 − 10 1{0}^{-10} . With the increase in the suction parameter ξ \xi , fluid velocity, spin velocity and temperature profiles decrease.

The Strategy of Innovative Development of Cross-Border E-Commerce Platforms in Vietnam

Over the past few years, Vietnam has been on the path of developing Cross Border Electronic Commerce (CBEC). E-business platform enterprise growth is scalabling transactions. CBEC’s economic effects are observed under four aspects as (1) Resource aggregate effect: cost effi-ciency, trading between producers and consumers is realized by E-business platforms; (2) Net-work effect: the positive correlation of platforms’ product or services with the quantity of con-sumers in increasing; (3) Innovation effect: startup costs for innovation (promotions, business models, new-coming products and services) have been recovered with E-business platforms. (4) The value of brand effect.

Effect of Various Parameters on the Bead Geometry and Flexural Strength of MIG Welded Joint

Metal inert gas welding is the process in which a continuous coil of consumable electrode is used with inert gas shielding. It was extensively being used for Aluminum and Mg Alloys. But due to other alternatives available for, the cost of inter gas prohibited the use of MIG welding of steels. After the introduction of carbondioxide as shielding gas the economical viability in welding of steels was realized. The quality of weld joing and its productivity is influenced by the parameters such as arc current, wire feed rate, voltage, welding speed, torch angle, , nozzle to plate distance, welding position and gas flow direction. In the present work effect of gas flow rate, voltage and current are studied using Taguchi L-9 orthogonal array. The flexural strength, tensile strenght and bead geometry for various trails are computed and the optimum combination is obtained.

Effect of Self-field and Loosening of Stacked Superconducting Tapes on Critical Current of a Single Pancake Coil

Research on superconducting systems is getting pace due to the increasing demand of efficient machines to fulfill the need of the society. Applications like motors, transformers and magnetic energy storage systems involve the pancake coils tightly bounded with the superconducting tapes. Moreover, all such devices are sensitive to the number of turns and operating current. Critical current of the superconducting tape is most important parameter while designing such machines as if operating current exceeds this value it will turn to a normal conductor. Critical current of the tape is further depending upon the operating temperature, external and self-field. In this work, effect of both self-field and degree of tightness or looseness on the critical current of the tape has been studied. The results showed that the critical current of the tape is significantly affected by both self-field and the inter-distance among the adjacent tapes.

EFFECT OF COATING TIME ON ELECTROCHEMICAL DEPOSITION OF MOLYBDENUM OXIDES THIN FILM ON THE SURFACE OF ANODIZED ALUMINUM PLATE FOR ULTRACAPACITOR ELECTRODE MATERIAL

In this work, effect of coating time on the structural, compositional and morphological properties of MoO3-coated Al2O3 plate for application as an electrode material for ultracapacitor was investigated. The 1[Formula: see text]cm [Formula: see text] 1[Formula: see text]cm aluminum plate was anodized by an electrochemical plating technique at 12[Formula: see text]V for 20 and 30[Formula: see text]min, respectively. MoO3 film was then coated on anodized aluminum plate over a range of coating time (2–10[Formula: see text]min, in intervals of 4[Formula: see text]min) at an applied voltage of 6[Formula: see text]V with constant electric current of 1[Formula: see text]A. X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM) were employed in the characterization of the MoO3/Al2O3 plate obtained. The SEM results obtained indicated that the coating time significantly affected the roughness and the surface area of the samples. The EDX analysis revealed the chemical composition element of Mo, O and Al and the result from XPS confirmed the existence of MoO3.