One of the types of intensification of heat transfer in heat exchange equipment is the installation of ribs for heat exchange elements. The use of such developed surfaces allows to improve the parameters of heat transfer due to the turbulence of flows and significantly increase the specific heat transfer surface. This study is devoted to the development of a mathematical model of the process of heat transfer of a finned surface of a specific design. The effectiveness of the proposed rib design is confirmed by both experimental research and computer simulation in ANSYS. The mathematical models obtained adequately describe the heat transfer, both under forced and free convection. The proposed models take into account both the convective component of heat transfer and thermal radiation, which allows it to be used for selection, which operates over a wide range of temperatures. The thermal resistance of the heat exchange element takes into account the coefficient of thermal conductivity of the material and the geometric shape of the wall. Particular attention should be paid to the study of the effect of temperature deformations on the wall of the ribbed element. This is especially important in cases of large differences in coolant temperatures in the tube and between the tubes spaces, since the heat exchangers are subject to linear and volumetric deformation. In such situations, the heat exchanger element may lose its elastic equilibrium shape, which may lead to residual deformation and, in some cases, the destruction of structural members. Installation of ribs on heat-exchange elements must be carried out taking into account both the possible temperature deformations and in terms of structural features.
Виробництво лікарських засобів визначеної якості, ефективності та безпечності ніколи не втрачало своєї актуальності. Сучасні системи забезпечення та керування якістюналежна виробнича практикавраховують існування критичних стадій та критичних параметрів процесу. Виробництво біологічних лікарських засобів способами культивування клітин або при використанні класичної ферментації відноситься до критичних стадій і потребує адекватних методик валідації процесів культивування в оригінальних ферментерах і ферментерах, у які внесені конструкційні зміни. Мета. Метою дослідження є апробація методик оцінки гідродинамічної обстановки у ферментері з класичним перемішувальним пристроєм і специфічним перемішувальним пристроєм V-blade на модельних середовищах та різних імітаційних об'єктах, а також визначення залежності змін гідродинамічних характеристик від основних критичних параметрів процесу. Методика реалізації. Гідродинамічна обстановка у ферментері характеризується специфічними параметрами потоків наявних фаз. Для визначення специфіки руху потоків запропоновано методи візуалізації та метод вирівнювання концентрації трасерачас гомогенізації. Результати. Методами візуалізації, що проведені при швидкісній зйомці, було виявлено специфічні особливості потоків для різних перемішувальних пристроїв. Більш адекватним і зручним для оцінки гідродинамічної обстановки у ферментері при зміні факторів зовнішнього оточення виявився метод введення хімічного трасера й оцінки часу гомогенізації за зміною рН. Висновки. Доведено можливість використання простої та легко відтворюваної методики для валідації ферментаційного обладнання при оцінці критичних стадій виробництва біологічних лікарських засобів способами культивування клітин або при використанні класичної ферментації. Показана висока ефективність мішалки V-blade порівняно з типовою конструкцією. Ключові слова: біотехнологія; належна виробнича практика; критична виробнича стадія; ферментер; гідродинаміка; мішалка V-blade. ASSESSMENT OF CRITICAL PARAMETERS OF THE CULTIVATING PROCESS IN BIOTECHNOLOGY OF ACTIVE PHARMACEUTICAL INGREDIENTS Background. The production of medicines of a certain quality, efficiency, and safety has never lost its relevance. Modern quality assurance and quality management systems-Good manufacturing practicetake into account the existence of critical stages and critical process parameters. The production of biological drugs by cell culture methods or using classical fermentation refers to the critical stages and they need adequate methods of validating the cultivation processes in the original fermenters and equipment to which structural changes have been made. Objective. The aim of the study is to test the methods for evaluating the hydrodynamic situation in a fermenter with a classic mixer and a specific V-blade mixer, in model environments and on various imitation objects, and to determine the dependence of the change in hydrodynamic characteristics on the main critical parameters of the process. Methods. The hydrodynamic situation in the fermenter is characteriz...
Today, heat transfer processes are present in almost all technological processes of various industries. In heat exchange processes, shell-and-tube heat exchangers are quite effective and easy to manufacture, as the long-term practice of using these devices has shown. Therefore, intensification of heat transfer processes, improvement and development of appropriate equipment is a very urgent task. The object of research is a heat-exchange element with special finning on heat-exchange tubes. The subject of research is the heat transfer processes implemented in a heat exchange element with special finning. The aim of the study is to determine the efficiency of heat transfer of the finned surface of the heat exchange element under conditions of forced convection and to evaluate its efficiency by means of experimental and computer research. This article presents a computer simulation that allows to adequately assess the efficiency of using various designs of finning elements of heat exchange equipment. This is confirmed by the convergence of the experimental data and the results of computer simulation (the discrepancy between the results of the experiment and computer simulation does not exceed 5 %). Experimental and computer studies have shown that the proposed technical solution is more effective than standard ones and can be used in the design of new equipment or improvement of the existing one.
This article presents the possibility of evaluating the efficiency of the heat exchange element with a special stamping plate, which is based on the results of computer simulation. The method is based on a comparative analysis of convective heat transfer models implemented in ANSYS using a k-ε turbulence model. To conduct the study, 3D models of three different types of cavity geometry formed between two heat exchange plates (flat plate, chevron plate, and plate with conical stampings) were built. Simulation was performed by finite element analysis in ANSYS for channels formed by the three types of plates, one of which is a new configuration. The results of hydrodynamic and heat exchange parameters allowed for establishing the efficiency of convective heat exchange for plates of known structures and to compare them with the proposed one. It was found that the plates with conical stamping form the smallest channels through which the fluid moves. The velocity of the coolant is uniform throughout the cross section of the channel and equal to 0.294 m/s; the value of the heat transfer coefficient is the largest of the three models and is 5339 W/(m K), while the pressure drop is 1060 Pa. Taking into account the simulation results, the best heat transfer parameters were shown by the channel formed by plates with conical stamping and the highest pressure drop. To increase the efficiency, indicated by the ratio of heat transfer coefficients to hydraulic resistance, the geometry of the plate with conical stamping was optimized. As a result of optimization, it was found that the optimal geometric parameters of the heat exchange plate with conical stamping were achieved at a 55° inclination angle and 1.5 mm height for the cone. The results of this study can be used in the design of heat exchange elements of new structures with optimal parameters for highly efficient heating of liquid coolants.
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