Alireza Rasekh

Natural convection from a vertical wall embedded in a non-Darcy porous medium filled with nanofluids

Purpose – This work aims to focus on the study of natural convection heat transfer characteristics in a vertical wall embedded in a non-Darcy porous medium filled with nanofluids. Design/methodology/approach – The governed partial differential equations are transformed into ordinary differential equations which are obtained by similarity solution and then have been solved through homotopy analysis method. Findings – The results show that Cu-water as nanofluid enhances the local Nusselt number more than other nanofluids. Originality/value – Nanoparticles and nanofluid enhance the local Nusselt number.

Effect of Rim Seal on Evaporation Loss from Khark Island Storage Tanks

Evaporation loss is a natural process in which part of liquid is turning to vapor and vanishing into the atmosphere. Crude oil compound from the several hydrocarbons in which some of them evaporate and could be released into the atmosphere at ambient temperature and pressure. This process causes to pollute the environment and has effects on crude oil quality. Any reduction in the loss will also have financial benefit. This makes the phenomena, crude oil evaporation loss an important issue, which should be carefully investigated and effects of various parameters be studied. The aim of the present work is to determine the evaporation rates from external floating storage tanks and to study the effects of rim seal type on the losses. In this study, a numerical scheme has been developed for estimating the time variations of the storage tank temperature and evaporative losses. The scheme validated against the measured values of the storage tank temperature at different times during a day, where reasonable agreements observed. Furthermore, the numerical value of monthly averaged evaporation losses also have been compared with the estimations based on the API AP-42 standard. In this paper, seal type on the evaporation loss has bee n investigated and determined. Further evaporate loss from rim seals for the Khark Island storage tanks are compared. Nine types of the primary/secondary seal configurations have been studied. The results unveiled that one type of the primary/secondary seal configuration has advantages over the other configurations in preventing evaporative loss.

The Effect of Crude Oil Type on Evaporation Loss From Khark Island Storage Tanks

Evaporation loss is a natural process that causes pollution of the environment and a significant effect on crude oil quality. The aim of the present work was to determine the evaporation rates from external floating storage tanks and to study the evaporation loss on various types of crude oil. In this study a numerical model/scheme was developed for estimating the temperature and evaporation loss of the storage tank with respect to time. Estimated values of tank temperature are further validated with experimental values for varied time zone of a day. In this study five different types of crude oil were taken and found that evaporation is directly proportional to the Reid vapor pressure and as Reid vapor pressure increases, the evaporation loss increases as well.

Calculation of Wax Precipitation Magnitude in Crude Oil Storage Tanks in Khark Island

During the different seasons of the year, the temperature of the oil tank goes up or down. The present work is composed of two parts, evaluation of the crude oil temperature and determining amount of wax precipitation. The numerical method has been developed for solving the energy equation and a thermodynamic model has been developed to predict wax precipitation based on average crude oil temperature. In the experimental investigation, a crude oil storage tank in Khark Island is selected as the case study and average crude oil temperature have been measured for two days and compared by the numerical result.

Novel Theoretical Approach on Exergy and Energy Performance Assessment of Cylindrical Solar Water Heater

AbstractIn this paper, a novel theoretical analysis is carried out for evaluating the thermal performance, exergy efficiency, and energy efficiency for a typical cylindrical solar water heater under given operating conditions. In this detailed mathematical modeling, a cylindrical coil tube in the shape of spiral rings, serves as a collector to the incident solar energy on the cylinder wall. The energy balance equations for both the fluid and tube have been established separately. The physical parameters that govern the system are identified. The governing differential equations have been solved for various values of the parameters. Because it is difficult to determine these parameters through experiments, the nondimensional theoretical approach has been applied in this research. Finally, the influences of these parameters on exergy and energy efficiency, which are the most significant factors in the design of a cylindrical solar water heater, are investigated. The results of this theoretical analysis are ...