During the blowdown process mass is usually evacuated from the gas zone, but also liquid might be released. The rate of release is dependent on density and pressure as well as the release area. 在排放過程中，物質通常是從氣體區排放的，但是也可釋放液體。釋放速率與密度、壓力以及釋放面積有關。
As pressure and temperature change, the properties of all materials change. This has to be considered in a prediction of a blowdown process. 隨著溫度和壓力的變化，所有材料的性質也變化。這在預測壹個排放過程中必須加以考慮。The main purpose of a blowdown process is as earlier
stated to maintain integrity of the equipment. The strength properties of the shell are the key factor on that matter. 排放過程的主要目的是如前面講到的那樣，保持設備的完整性。外殼的強度性能是該問題的主要因數。The strength is dependent on the inside pressure as well as the
support forces. 這壹強度與內部壓力，以及支撐力有關。If the exposing forces produce stress that exceeds the ultimate tensile stress (UTS) in some regions, the integrity of the equipment is no longer maintained. 如果暴露的力產生超過極限拉伸應力（UTS）壹定範圍的應力，設備就不在能保持完整性。In the design phase of a process plant, these aspects are crucial and must be included as a dimensional factor. For that reason prediction of the blowdown process is essential. Lately some new standards has been introduced to the industry on this matter [3] and [4]. 在工藝設備的設計階段，這些方面都是很關鍵的，而且必須作為尺寸因素被包括在內。由於這個原因，排放過程的預測是至關重要的。最近，壹些新的標準已經采用於本行業的這壹問題3，4。
VessFire [1] and [2] is a multi physics system designed for calculation of this kind of problems. It has been applied for some time in the oil and process industry on many projects. The system satisfies the requirements for predictions outlined in [3] and [4]. It includes all aspects described above including
integrity of the shell. As part of the verification process some experiments where performed. Some of the experiments are presented here. VessFire1，2是壹種設計用於計算這類問題的多物理系統。它被用於石油和加工行業的很多項目上已有壹些時間。該系統滿足文獻3和4中概述的預測的要求。它包含了上面描述的所有方面，包括外殼的完整性。作為驗證過程的壹部分，進行了壹些實驗。有些實驗在這裏做了介紹。
EXPERIMENTAL STUDY
實驗研究
The purpose of the experiments was to investigate the evaporation process and the heat transfer to the liquid and vapour. In a complex system it is important to reduce unknown parameters as far as possible. 實驗的目的是研究蒸發過程和向液體和蒸汽的熱傳導。在壹個復雜系統中，盡可能減少未知參數是很重要的。Exposure from a flame is difficult to control. Flux measurements are point values and not necessarily representative for the average exposure. 暴露於火焰中很難控制。 （熱）通量測量是壹些點值，而且不壹定具有平均暴露的代表性In order to control the heat exposure it was decided to apply an electric heating system. The system and the verification of the system is described in [5], [6] and [8]. 為了控制熱暴露，我們決定采用電熱系統。該系統和該系統的驗證在文獻5，6，8中敘述。
The furnace was built inside a supporting tube. Figure 2 shows a general arrangement of the
experimental outfit. 電熱爐建在支撐管內。圖2示出了該實驗裝備的總的安排。A 0.05 mm stainless steel foil formed as a tube, 300 mm in diameter, generated the heat. The power supply was based on a 3-phase alternating current system giving 48 Volt output as maximum. The top exposure had a limit of 300 kW. The foil had a surface of about 1 m2, giving a heat flux up to 300 kW/m2. 壹根由0.05mm不銹鋼箔形成的、直徑300mm的管子，產生熱。電源是3相的交流系統，最大提供48V的輸出。頂部的暴露機箱為300kW。 不銹鋼箔的表面約1m2，能提供高達300kW/m2的熱通量。
問題補充：The power input could be continuously regulated from zero to maximum load. Each experiment was started from zero and brought up to the required load within a few seconds. After that the surface temperature of the heating foil was kept constant during the exposure period. Experiments with both dry objects as well as water filled object were performed. 功率輸入可以從零到最大負載連續調節。每壹次實驗都從零開始，並在幾秒鐘內升高到所要求的負載。在那以後，加熱箔的表面溫度就在暴露周期內保持恒定。對幹燥物體和充水物體都進行了實驗。 In this paper only water filled experiments are presented Figure 2 General arrangements drawing of the experimental furnace including the specimen and its support Figure 3 Illustration of the heating unit. 在本文中，只介紹了充水的實驗。圖2為包含樣本在內的實驗爐及其支撐的總安排圖。圖3為發熱單元的示意圖。The black part is copper conductors for the foil. The grey part is the heating foil exposing the specimen. The foil is equipped with thermo-elements all marked H, except H5 which is the temperature in a copper ring and H6 which is the temperature between the insulation and the supporting tube. 黑色的部分是用於不銹鋼箔的銅導體。灰色的部分是是樣本熱暴露的發熱箔。不銹鋼箔配備以熱電元件，除了H5外，全都標上H，H5是銅環中的溫度，而H6是絕緣和支撐管之間的溫度。