Research on the falling film flow and heat transfer characteristics of FLNG spiral wound heat exchanger under sea conditions

As the key equipment of floating liquefied natural gas(FLNG)process,the performance of spiral wound heat exchanger(SWHE)influences operation costs and reliability of the whole system.The sea conditions destroy the falling film flow state of the refrigeration and then affect the heat transfer performance of FLNG SWHE.In order to design and optimize the SWHE,a cryogenic experimental device of FLNG process and a numerical model of falling film flow have been constructed to study the effects of sea conditions on the falling film flow and heat transfer characteristics of SWHE.The cryogenic experimental results show that the pitching conditions have larger effects on the heat transfer performance than yawing.Under the pitching angle of 7°,the natural gas temperature and gaseous refrigerant temperature increase by 3.22°C and 7.42°C,respectively.The flow rates of refrigerant and feed natural gas have a great impact on the heat transfer performance of SWHE under pitching and compound sloshing conditions.When the tilt angle increases to 9°,the tube structure with outer diameter D=8 mm and pipe spacing S=4 mm is recommended to reduce the drying area of the pipe wall surface.

Synthesis and characterization of polymeric responsive CMC/Pectin hydrogel films loaded with Tamarix aphylla extract as potential wound dressings

The fourth most predominant overwhelming type of trauma is burn injuries worldwide.Ideal wound healing dressings help in the wound healing process in a lower time with less pain.Commonly used dry wound dressing,like absorbent gauze or absorbent cotton,possess limited therapeutic effects and require repeated use,which further exaggerates patients’suffering.In contrast,hydrogels films present a promising alternative to improve healing by guaranteeing a moisture balance at the wound site.The aim of the current study was to synthesize Tamarix aphylla(T.aphylla)extract-loaded hydrogel film with Na-CMC and pectin and to study their wound healing properties.The Na-CMC/Pectin hydrogels films were synthesized and characterized for HPLC analysis,FTIR,surface morphology,rheology,tensile strength,swelling behavior,drug release kinetics,and in vivo wound healing in an animal model.FTIR confirmed the existence of strong interaction between both polymers but no interaction with the extract.SEM photographs showed successful embedding of extract in small pores of hydrogel film and showed smooth and homogenous morphology.Rheological and texture profiles indicated that hydrogels behaved as strong gels.Swelling and erosion were dependent on the amount of the CMC.HPLC showed drug content of three selected formulation(A3,E3 and S3)as 85±0.1%,82.5±0.4%and 80±0.3%,respectively.The release of the drug from the hydrogel was controlled by a Fickian diffusion mechanism.In vivo wound healing activity of hydrogel film confirmed that T.aphylla extract successfully promoted healing rate by significantly reducing(P<0.05)the size of wound closure compared to the control group,evidenced by intensive collagen formation in histopathological and biochemical analysis.The capability of these hydrogels for burn wounds could be valuable for medical uses as a new window of safe and effective medication.

The Use of an Innovative Film-Forming Wound Dressing in the Treatment of Radiation Dermatitis during Concomitant Chemotherapy

There is currently no consensus regarding the management of acute cutaneous reactions emerging from a concurrent treatment of radio-and chemotherapy, the goal of this case study series is to provide scientific evidence based on clinical practice regarding the efficacy of a film-forming wound dressing for patients receiving combined cancer therapy, in particular examples where the reactions are expected to be intense. In all the described cases, management of acute skin reactions allowed the cancer therapy to be finalized, instead of being interrupted due to an increase in the severity of the reactions. It has been shown in the current literature that the lack of compliance with treatment plans correlates with poorer clinical outcome. Evidence from the cases presented suggest that the studied dressing is safe and efficacious in the treatment and the prevention of acute cutaneous reactions arising from combined cancer therapy.

Numerical and experimental study on the falling film flow characteristics with the effect of co-current gas flow in hydrogen liquefaction process

Liquid hydrogen storage and transportation is an effective method for large-scale transportation and utilization of hydrogen energy. Revealing the flow mechanism of cryogenic working fluid is the key to optimize heat exchanger structure and hydrogen liquefaction process(LH2). The methods of cryogenic visualization experiment, theoretical analysis and numerical simulation are conducted to study the falling film flow characteristics with the effect of co-current gas flow in LH2spiral wound heat exchanger.The results show that the flow rate of mixed refrigerant has a great influence on liquid film spreading process, falling film flow pattern and heat transfer performance. The liquid film of LH2mixed refrigerant with column flow pattern can not uniformly and completely cover the tube wall surface. As liquid flow rate increases, the falling film flow pattern evolves into sheet-column flow and sheet flow, and liquid film completely covers the surface of tube wall. With the increase of shear effect of gas-phase mixed refrigerant in the same direction, the liquid film gradually becomes unstable, and the flow pattern eventually evolves into a mist flow.

Numerical Study of Heat Transfer Characteristic for Subcooled Falling Film outside the Shaped Tubes under Rolling Motion

The heat transfer performance of spiral wound heat exchanger used in the floating liquefied natural gas(FLNG)may be significantly affected by the sloshing conditions.In this paper,a three-dimensional numerical model combined with the dynamic mesh technology is conducted to study subcooled falling film heat transfer under static and sloshing conditions.The three-dimensional velocity distribution of the liquid film on the shell side is observed.The effects of cross-section shape of heat exchange tubes,Reynolds numbers and sloshing parameters on heat transfer characteristics are analyzed.The results indicate that the heat transfer performance of the egg-shaped tube is superior to that of the elliptical and circular tube under both static and sloshing conditions due to significant heat transfer improvement in the lower half of the tube.The heat transfer coefficients of three different kinds of tubes decrease under sloshing conditions.When the rolling amplitude is 6°,the average heat transfer coefficients of the circular tube,elliptical tube and egg-shaped tube are reduced by 2.1%,3.7%and 4.9%respectively.Under the current sloshing parameters,increasing the rolling amplitude,the heat transfer coefficients of three different tubes are slightly increased,while the sloshing period has little effect on heat transfer.The egg-shaped tube and elliptical tube are greatly affected by sloshing motion at the low Reynolds number,while the effect is relatively small at the high Reynolds number.

圆管和扁形管的绕管式换热器壳侧流体降膜流动特性

为探究异型管绕管式换热器壳侧流体降膜流动和分布特性,建立了绕管式换热器三维物理模型,并基于流体体积(VOF)法多相流模型进行了数值模拟,对比分析了圆管和扁形管的管外流体降膜流动特性。结果表明:圆管和扁形管的管外轴向降膜流动分布均呈现“波谷-波峰-波谷”形状;扁形管的管外流体降膜流动速度明显大于圆管;圆管的管外液膜最薄处为圆周角120°处,扁形管的管外液膜最薄处在90°~120°之间;随着管间距的增加,圆管和扁形管的管外液膜平均厚度均呈下降趋势,扁形管周向液膜平均厚度比等周长圆管小10%~29%;随着缠绕角的增加,扁形管的管周向液膜平均厚度比等周长圆管小4%~28%。因此,推荐使用扁形管替代圆管作为绕管式换热器的缠绕管。

无菌生物护创膜在严重创伤致软组织缺损创面早期治疗中的应用效果分析

目的探讨无菌生物护创膜在严重创伤致软组织缺损创面早期治疗中的临床效果。方法选取2019年1月至2020年12月苏州大学附属第一医院收治的40例严重创伤致软组织缺损患者作为研究对象,按照不同治疗方法将其分为护创膜组(20例)与纱布组(20例),护创膜组患者在对症支持治疗的基础上局部创面早期行无菌生物护创膜联合负压封闭引流治疗,纱布组患者在对症支持治疗的基础上局部创面早期行灭菌凡士林纱布联合负压封闭引流治疗,对比观察两组患者创面疼痛评分、创面基底准备时间、创面愈合时间、住院时间、创面一次性愈合比值以及术后并发症发生情况。结果护创膜组患者治疗第7天时创面视觉模拟评分法(VAS)评分明显低于纱布组(Z=-2969,P=0003),创面基底准备时间、创面愈合时间及住院时间均明显短于纱布组(Z/t=-2394、-2782、3186,P=0017、0005、0003),而创面一次性愈合比值与纱布组无明显差异(χ^(2)=0173,P=0677);护创膜组患者术后并发症发生率为150%,与纱布组患者的术后并发症发生率200%无明显差异(χ^(2)=0173,P=0677)。结论无菌生物护创膜可有效减轻严重创伤致软组织缺损创面的疼痛程度,缩短创面基底准备时间、创面愈合时间及住院时间,具有较高的临床应用价值。

马应龙麝香痔疮膏对老年Ⅱ~Ⅲ期压疮患者炎症反应及创面愈合情况的影响

目的探讨马应龙麝香痔疮膏对老年Ⅱ~Ⅲ期压疮患者炎症反应及创面愈合情况的影响。方法按随机数字表法分配原则将2020年1月—2022年6月医院收治的68例老年Ⅱ~Ⅲ期压疮患者分为对照组(34例)和治疗组(34例)。两组均进行常规消毒清创,对照组在常规消毒清创基础上给予利凡诺创伤膏纱条外敷,治疗组在常规消毒清创基础上给予马应龙麝香痔疮膏纱条外敷,两组均连续治疗2周。比较两组治疗2周后的疗效,临床症状改善情况,治疗前、治疗2周后的创面愈合情况、疼痛程度、炎症指标及血管内皮功能指标。结果与对照组比较,治疗组治疗2周后的总有效率较高[85.29%(29/34)vs 55.88%(19/34),P<0.05]。与对照组比较,治疗组渗液消失时间、新生肉芽组织生长时间及压疮愈合时间均较短(P<0.05)。与治疗前比较,治疗2周后,两组创面面积、创面组织类型、渗液量、视觉模拟评分法(visual analogue scale,VAS)评分及血清肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)、白细胞介素-6(interleukin-6,IL-6)、白细胞介素-1β(interleukin-1β,IL-1β)、C反应蛋白(C-reactive protein,CRP)水平均降低,治疗组低于对照组(P<0.05);两组血清血管内皮生长因子(vascular endothelial growth factor,VEGF)、转化生长因子-β1(transforming growth factor-β1,TGF-β1)、表皮细胞生长因子(epidermal growth factor,EGF)水平均升高,治疗组高于对照组(P<0.05)。结论马应龙麝香痔疮膏可明显减轻老年Ⅱ~Ⅲ期压疮患者炎症反应,改善血管内皮功能,缓解创面疼痛,进而有助于改善患者临床症状,促进创面愈合,疗效显著。

改良式负压贴膜法在骶尾部压疮患者中的应用效果观察

目的:探讨改良式负压贴膜法在骶尾部压疮患者治疗中的应用效果。方法:选择2021年3月—2023年7月收治的骶尾部Ⅳ期压疮患者76例,按入院顺序分为对照组和观察组,每组38例。对照组采取传统单层贴膜负压封闭引流技术(VSD)治疗,观察组采取内层贴膜缝合固定+外层贴膜VSD治疗。比较两组VSD治疗情况、压疮愈合计分量表(PUSH)评分及创面愈合效果。结果:观察组首次贴膜维持时间长于对照组,首次肉芽出现时间、肉芽布满创面时间短于对照组,创面VSD治疗次数少于对照组,差异均有统计学意义(P<0.05)。治疗前,两组PUSH评分对比,差异无统计学意义(P>0.05);治疗4周后,两组PUSH评分均低于治疗前,且观察组低于对照组,差异有统计学意义(P<0.05)。观察组创面愈合总有效率高于对照组,差异有统计学意义(P<0.05)。结论:改良式负压贴膜法在骶尾部VSD治疗患者中应用效果良好,能够延长贴膜维持时间,加快肉芽生长,减轻压疮严重程度,促进创面愈合。

聚维酮碘和利凡诺对糖尿病足溃疡创面细菌载量影响的对比研究

目的应用聚维酮碘与利凡诺对糖尿病足溃疡(diabetic foot ulcers,DFUs)创面进行干预,观察其对创口表面细菌载量的影响,评价二者在DFUs换药的效果。方法2006年3月-2007年3月,选取符合选择标准的30例患者进行试验。男18例,女12例;年龄46～78岁,平均59.8岁。创面范围3cm×2cm～15cm×10cm。病程6周～6个月,平均2.1个月。采用随机对照的方法按患者就诊次序分为3组,每组10例。创面清创生理盐水冲洗后,A组以生理盐水,B组以0.3%聚维酮碘,C组以0.1%利凡诺分别湿敷创面5min,再以生理盐水冲洗,冲洗前后及冲洗后24h取标本。将各标本以大豆胰蛋白酶肉汤10倍稀释后行细菌培养计数,对比冲洗前后各组创面细菌载量的变化,分析各组干预结果的差异性。结果各标本培养菌落形成良好,菌落清晰。各组冲洗后即刻细菌培养结果细菌载量均有明显减少,各组间比较差异无统计学意义(P>0.05)。冲洗24h后细菌培养A组和C组细菌载量变化较小,B组细菌培养菌落数量明显减少,细菌载量变化明显,B组与A、C组比较,差异有统计学意义(P<0.05),A组和C组间差异无统计学意义(P>0.05)。结论聚维酮碘和利凡诺均具有较好的组织渗透及清除细菌的作用,糖尿病足局部使用能明显减少创面生物载荷,对杀灭细菌减轻感染有明显作用,聚维酮碘较利凡诺具有更长久的抑菌或杀菌作用。

利凡诺涂膜剂的研制与应用

本文报道用羧甲基纤维素钠作成膜材料,研制了利凡诺创面用涂膜剂,直接用于二氧化碳激光治疗后的皮肤创面,获得了满意的治疗效果。

两种手术薄膜铺巾法对剖宫产手术切口感染影响的研究

目的：观察两种不同手术薄膜铺巾法对剖宫产手术切口感染的影响。方法选取2011年10月至2012年4月该院剖宫产手术396例，分为两组：A组198例，皮肤消毒后先铺巾后贴薄膜，B组198例，皮肤消毒后先贴薄膜后铺巾，在手术开始切皮后及手术结束缝皮前提取切口表面涂擦液送细菌培养观察菌落数，并在关腹时观察切口周围布敷料的浸湿例数，同时在术后5～7d随访手术切口的愈合，以观察两种手术薄膜铺巾法对手术切口感染的影响。结果两组在手术开始切皮后切口表面涂擦液菌落生长数均为0例，差异无统计学意义（ P＞0．05）；关腹时切口周围布类敷料浸湿例数，A组为16例，B组为47例，差异有统计学意义（P＜0．05）；A组手术结束缝皮前切口表面涂擦液菌落生长数为1例，B组为4例，差异无统计学意义（P＞0．05）；A组术后切口感染为0例，B组为1例，差异无统计学意义（P＞0．05）。结论两种不同手术薄膜铺巾法对剖宫产手术切口感染无直接影响，但对布敷料浸湿程度的影响有差异，应加强手术切口感染的综合防控。

防水透气聚氨酯薄膜及涂层的研究进展

综述了防水透气性聚氨酯薄膜及涂层的结构、原理及各种成型加工工艺及其应用。重点阐述了防水透气性聚氨酯薄膜及涂层在衣物及医用制品如运动服、伤口敷料、外科手术服及医护衣服等方面的应用。

半导体激光联合3M伤口保护膜治疗老年人失禁性皮炎的疗效观察

目的:观察半导体激光联合3M伤口保护膜治疗老年人失禁性皮炎的临床疗效。方法:随机将49例患者分为治疗组和对照组。治疗组用生理盐水清洗创面后进行半导体激光局部照射再使用3M伤口保护膜涂抹患处。对照组在生理盐水清洗创面后只使用3M伤口保护膜涂抹患处。结果:两组在治愈率及总有效率有显著性差异(P〈0.05)。结论:半导体激光治疗老年人失禁性皮炎有明显疗效,它能促进老年人失禁性皮炎的恢复。

绕管式换热器壳侧降膜流动和相变传热的数值模拟

为了定量描述绕管式换热器壳侧降膜蒸发特性并进而优化换热器结构,建立了绕管式换热器壳侧降膜蒸发过程流动与传热的数值模型。首先对降膜流动过程中流型变化和传热传质机理进行分析;通过对降膜流动过程液膜所受表面张力、重力和剪切力的计算,实现层状流、柱状流和滴状流等不同流型的模拟;通过管壁面和气液交界面的组分守恒建立降膜蒸发过程的传质子模型,并基于传质速率计算得出潜热传热速率。将数值模拟结果与已有文献中实验数据进行了对比,结果显示89%的模拟数据与实验数据偏差不超过25%;模拟结果与实验数据吻合较好。基于提出的模型,对不同工况下的绕管式换热器壳侧降膜蒸发传热传质规律进行了分析。

创面用复方喷雾膜剂的制备及其性质研究

目的研制创面用复方喷雾膜剂(compound spraying film,CSF),并进行质量评价。方法采用物理混合法制备CSF,评价其成膜性能和机械性能;以HPLC法测定其含量和释药行为;建立大鼠创面模型,评价其创面愈合效果。结果 CSF的成膜温度为(30±2)℃,成膜时间为(29±6)s,机械性质良好。CSF含人参皂苷(GRg1)(5.82±0.08)mg/g,体外释药以骨架溶蚀为主,释药动力学符合零级方程和Ritger-Peppas方程特征。CSF用于治疗大鼠背部机械创伤,愈合百分率均显著高于复方水溶液组和空白喷雾膜剂组(P<0.05)。结论 CSF使用方便,性质优良,促愈效果明显,具有良好的应用前景。

伤口护理膜联合卫生棉条在神经外科腹泻护理中的效果评价

目的评价伤口护理膜联合卫生棉条在神经外科腹泻护理中的效果。方法将100例神经外科腹泻患者随机分成两组,观察组选用伤口护理膜联合卫生棉条进行护理,对照组选用常规方法进行护理,观察两组患者肛周皮肤损伤情况、肛周皮肤护理次数,并进行统计学处理。结果观察组与对照组在肛周皮肤损伤、肛周皮肤护理次数比较均具有统计学显著意义(P<0.01)。结论伤口护理膜联合卫生棉条能明显降低肛周皮肤损伤概率,能减轻护理工作量,是一种非常有效的腹泻护理方法。

壳聚糖敷料在创伤中的新应用

壳聚糖由甲壳质经脱乙酰基而得。本文介绍了壳聚糖纤维和创伤敷料研制的历史及发展趋势。文中扼要描述了壳聚糖的性质、制备方法和创伤敷料的制备方法及临床应用。

安普贴薄膜在新型无创耳模矫正技术中的应用研究

目的探讨安普贴薄膜在新型无创耳模矫正技术中的治疗作用和预防、治疗压力性损伤的临床效果。方法选择2018年10月~2019年3月患有耳廓畸形并接受美国EarWell耳矫正器治疗121例婴幼儿为研究对象,年龄7天~2岁。签署知情同意,采用美国Earwel耳矫正器进行矫正治疗。随机分为实验组和对照组,实验组61例据耳廓大小选择合适型号矫形器,将安普贴薄膜贴于耳廓畸形部位、牵引器及耳颊矫正器受压部位,根据耳廓畸形类型先用安普贴薄膜塑型再固定耳廓牵引器和耳颊矫正器。对照组60例按照常规方法用耳廓牵引器和耳颊矫正器直接牵拉治疗,无塑形及保护性隔离。对比观察受压部位皮肤压力性损伤情况、复诊时间、家长满意度,评估矫正效果并记录。结果比较两组患儿受压部位皮肤压力性损伤的情况、复诊时间及矫正效果。皮肤压力性损伤情况:实验组仅1例皮肤发红,无皮损情况发生;对照组15例出现局部皮肤完整,颜色暗红,压之不褪色;9例出现局部皮肤破损,伴有粉红色的伤口床,无软骨暴露,周围无腐肉;1例耳甲矫正器受压部位皮肤破溃,软骨外露。复诊时间:实验组复诊时间(8.41±0.99)天,对照组复诊时间(5.67±0.95)天。矫正效果:实验组不满意0例,一般3例,满意58例;对照组不满意6例,一般10例,满意44例。结论安普贴薄膜能有效预防无创耳矫正术中的压力性损伤并对受压部位有治疗作用。安普贴薄膜对耳廓畸形特别是耳轮畸形有塑型作用。能有效延长患儿的复诊时间,减少复诊次数。可以推广应用。